draft-ietf-opsawg-oam-overview-16.txt   rfc7276.txt 
Operations and Management Area Working Group T. Mizrahi
Internet Draft Marvell Internet Engineering Task Force (IETF) T. Mizrahi
Intended status: Informational N. Sprecher Request for Comments: 7276 Marvell
Expires: September 2014 Nokia Solutions and Networks Category: Informational N. Sprecher
ISSN: 2070-1721 Nokia Solutions and Networks
E. Bellagamba E. Bellagamba
Ericsson Ericsson
Y. Weingarten Y. Weingarten
June 2014
March 28, 2014 An Overview of
Operations, Administration, and Maintenance (OAM) Tools
An Overview of
Operations, Administration, and Maintenance (OAM) Tools
draft-ietf-opsawg-oam-overview-16.txt
Abstract Abstract
Operations, Administration, and Maintenance (OAM) is a general term Operations, Administration, and Maintenance (OAM) is a general term
that refers to a toolset for fault detection and isolation, and for that refers to a toolset for fault detection and isolation, and for
performance measurement. Over the years various OAM tools have been performance measurement. Over the years, various OAM tools have been
defined for various layers in the protocol stack. defined for various layers in the protocol stack.
This document summarizes some of the OAM tools defined in the IETF in This document summarizes some of the OAM tools defined in the IETF in
the context of IP unicast, MPLS, MPLS Transport Profile (MPLS-TP), the context of IP unicast, MPLS, MPLS Transport Profile (MPLS-TP),
pseudowires, and TRILL. This document focuses on tools for detecting pseudowires, and Transparent Interconnection of Lots of Links
and isolating failures in networks and for performance monitoring. (TRILL). This document focuses on tools for detecting and isolating
Control and management aspects of OAM are outside the scope of this failures in networks and for performance monitoring. Control and
document. Network repair functions such as Fast Reroute (FRR) and management aspects of OAM are outside the scope of this document.
protection switching, which are often triggered by OAM protocols, are Network repair functions such as Fast Reroute (FRR) and protection
also out of the scope of this document. switching, which are often triggered by OAM protocols, are also out
of the scope of this document.
The target audience of this document includes network equipment The target audience of this document includes network equipment
vendors, network operators and standards development organizations, vendors, network operators, and standards development organizations.
and can be used as an index to some of the main OAM tools defined in This document can be used as an index to some of the main OAM tools
the IETF. This document provides a brief description of each of the defined in the IETF. At the end of the document, a list of the OAM
OAM tools in the IETF. At the end of the document a list of the OAM
toolsets and a list of the OAM functions are presented as a summary. toolsets and a list of the OAM functions are presented as a summary.
Status of this Memo Status of This Memo
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Table of Contents Table of Contents
1. Introduction ................................................. 4 1. Introduction ....................................................4
1.1. Background .............................................. 4 1.1. Background .................................................5
1.2. Target Audience.......................................... 5 1.2. Target Audience ............................................6
1.3. OAM-related Work in the IETF ............................ 6 1.3. OAM-Related Work in the IETF ...............................6
1.4. Focusing on the Data Plane .............................. 7 1.4. Focusing on the Data Plane .................................7
2. Terminology .................................................. 7 2. Terminology .....................................................8
2.1. Abbreviations ........................................... 7 2.1. Abbreviations ..............................................8
2.2. Terminology used in OAM Standards ....................... 9 2.2. Terminology Used in OAM Standards .........................10
2.2.1. General Terms ...................................... 9 2.2.1. General Terms ......................................10
2.2.2. Operations, Administration and Maintenance ......... 9 2.2.2. Operations, Administration, and Maintenance ........10
2.2.3. Functions, Tools and Protocols .................... 10 2.2.3. Functions, Tools, and Protocols ....................11
2.2.4. Data Plane, Control Plane and Management Plane .... 11 2.2.4. Data Plane, Control Plane, and Management Plane ....11
2.2.5. The Players ....................................... 12 2.2.5. The Players ........................................12
2.2.6. Proactive and On-demand Activation ................ 12 2.2.6. Proactive and On-Demand Activation .................13
2.2.7. Connectivity Verification and Continuity Checks ... 13 2.2.7. Connectivity Verification and Continuity Checks ....14
2.2.8. Connection Oriented vs. Connectionless Communication14 2.2.8. Connection-Oriented vs. Connectionless
2.2.9. Point-to-point vs. Point-to-multipoint Services ... 14 Communication ......................................15
2.2.10. Failures ......................................... 15 2.2.9. Point-to-Point vs. Point-to-Multipoint Services ....16
3. OAM Functions ............................................... 16 2.2.10. Failures ..........................................16
4. OAM Tools in the IETF - a Detailed Description .............. 16 3. OAM Functions ..................................................17
4.1. IP Ping ................................................ 17 4. OAM Tools in the IETF - A Detailed Description .................18
4.2. IP Traceroute .......................................... 17 4.1. IP Ping ...................................................18
4.3. Bidirectional Forwarding Detection (BFD) ............... 18 4.2. IP Traceroute .............................................19
4.3.1. Overview .......................................... 18 4.3. Bidirectional Forwarding Detection (BFD) ..................20
4.3.2. Terminology ....................................... 19 4.3.1. Overview ...........................................20
4.3.3. BFD Control ....................................... 19 4.3.2. Terminology ........................................20
4.3.4. BFD Echo .......................................... 19 4.3.3. BFD Control ........................................20
4.4. MPLS OAM ............................................... 20 4.3.4. BFD Echo ...........................................21
4.4.1. LSP Ping .......................................... 20 4.4. MPLS OAM ..................................................21
4.4.2. BFD for MPLS ...................................... 21 4.4.1. LSP Ping ...........................................21
4.4.3. OAM for Virtual Private Networks (VPN) over MPLS .. 21 4.4.2. BFD for MPLS .......................................22
4.5. MPLS-TP OAM ............................................ 21 4.4.3. OAM for Virtual Private Networks (VPNs) over MPLS ..23
4.5.1. Overview .......................................... 21 4.5. MPLS-TP OAM ...............................................23
4.5.2. Terminology ....................................... 22 4.5.1. Overview ...........................................23
4.5.3. Generic Associated Channel ........................ 24 4.5.2. Terminology ........................................24
4.5.4. MPLS-TP OAM Toolset ............................... 24 4.5.3. Generic Associated Channel .........................25
4.5.4.1. Continuity Check and Connectivity Verification 25 4.5.4. MPLS-TP OAM Toolset ................................25
4.5.4.2. Route Tracing ................................ 25 4.5.4.1. Continuity Check and Connectivity
4.5.4.3. Lock Instruct ................................ 25 Verification ..............................26
4.5.4.4. Lock Reporting ............................... 25 4.5.4.2. Route Tracing .............................26
4.5.4.5. Alarm Reporting .............................. 26 4.5.4.3. Lock Instruct .............................27
4.5.4.6. Remote Defect Indication ..................... 26 4.5.4.4. Lock Reporting ............................27
4.5.4.7. Client Failure Indication .................... 26 4.5.4.5. Alarm Reporting ...........................27
4.5.4.8. Performance Monitoring ....................... 26 4.5.4.6. Remote Defect Indication ..................27
4.5.4.8.1. Packet Loss Measurement (LM) ............ 26 4.5.4.7. Client Failure Indication .................27
4.5.4.8.2. Packet Delay Measurement (DM) ........... 27 4.5.4.8. Performance Monitoring ....................28
4.6. Pseudowire OAM ......................................... 27 4.5.4.8.1. Packet Loss Measurement (LM) ...28
4.6.1. Pseudowire OAM using Virtual Circuit Connectivity 4.5.4.8.2. Packet Delay Measurement (DM) ..28
Verification (VCCV) ...................................... 27 4.6. Pseudowire OAM ............................................29
4.6.2. Pseudowire OAM using G-ACh ........................ 29 4.6.1. Pseudowire OAM Using Virtual Circuit
4.6.3. Attachment Circuit - Pseudowire Mapping ........... 29 Connectivity Verification (VCCV) ...................29
4.7. OWAMP and TWAMP......................................... 29 4.6.2. Pseudowire OAM Using G-ACh .........................30
4.7.1. Overview .......................................... 29 4.6.3. Attachment Circuit - Pseudowire Mapping ............30
4.7.2. Control and Test Protocols ........................ 30 4.7. OWAMP and TWAMP ...........................................31
4.7.3. OWAMP ............................................. 31 4.7.1. Overview ...........................................31
4.7.4. TWAMP ............................................. 31 4.7.2. Control and Test Protocols .........................32
4.8. TRILL .................................................. 32 4.7.3. OWAMP ..............................................32
5. Summary ..................................................... 32 4.7.4. TWAMP ..............................................33
5.1. Summary of OAM Tools ................................... 32 4.8. TRILL .....................................................33
5.2. Summary of OAM Functions ............................... 35 5. Summary ........................................................34
5.3. Guidance to Network Equipment Vendors .................. 36 5.1. Summary of OAM Tools ......................................34
6. Security Considerations ..................................... 36 5.2. Summary of OAM Functions ..................................37
7. IANA Considerations ......................................... 37 5.3. Guidance to Network Equipment Vendors .....................38
8. Acknowledgments ............................................. 37 6. Security Considerations ........................................38
9. References .................................................. 37 7. Acknowledgments ................................................39
9.1. Normative References ................................... 37 8. References .....................................................39
9.2. Informative References ................................. 37 8.1. Normative References ......................................39
Appendix A. List of OAM Documents .............................. 43 8.2. Informative References ....................................39
A.1. List of IETF OAM Documents ............................. 43 Appendix A. List of OAM Documents ................................ 46
A.2. List of Selected Non-IETF OAM Documents ................ 48 A.1. List of IETF OAM Documents ............................... 46
A.2. List of Selected Non-IETF OAM Documents .................. 50
1. Introduction 1. Introduction
OAM is a general term that refers to a toolset for detecting, "OAM" is a general term that refers to a toolset for detecting,
isolating and reporting failures and for monitoring the network isolating, and reporting failures, and for monitoring network
performance. performance.
There are several different interpretations to the "OAM" acronym. There are several different interpretations of the "OAM" acronym.
This document refers to Operations, Administration and Maintenance, This document refers to Operations, Administration, and Maintenance,
as recommended in Section 3 of [OAM-Def]. as recommended in Section 3 of [OAM-Def].
This document summarizes some of the OAM tools defined in the IETF in This document summarizes some of the OAM tools defined in the IETF in
the context of IP unicast, MPLS, MPLS Transport Profile (MPLS-TP), the context of IP unicast, MPLS, MPLS Transport Profile (MPLS-TP),
pseudowires, and TRILL. pseudowires, and TRILL.
This document focuses on tools for detecting and isolating failures This document focuses on tools for detecting and isolating failures
and for performance monitoring. Hence, this document focuses on the and for performance monitoring. Hence, this document focuses on the
tools used for monitoring and measuring the data plane; control and tools used for monitoring and measuring the data plane; control and
management aspects of OAM are outside the scope of this document. management aspects of OAM are outside the scope of this document.
Network repair functions such as Fast Reroute (FRR) and protection Network repair functions such as Fast Reroute (FRR) and protection
switching, which are often triggered by OAM protocols, are also out switching, which are often triggered by OAM protocols, are also out
of the scope of this document. of the scope of this document.
1.1. Background 1.1. Background
OAM was originally used in traditional communication technologies OAM was originally used in traditional communication technologies
such as E1 and T1, evolving into PDH and then later in SONET/SDH. ATM such as E1 and T1, evolving into Plesiochronous Digital Hierarchy
was probably the first technology to include inherent OAM support (PDH) and then later into Synchronous Optical Network / Synchronous
from day one, while in other technologies OAM was typically defined Digital Hierarchy (SONET/SDH). ATM was probably the first technology
in an ad hoc manner after the technology was already defined and to include inherent OAM support from day one, while in other
deployed. Packet-based networks were traditionally considered technologies OAM was typically defined in an ad hoc manner after the
unreliable and best-effort. As packet-based networks evolved, they technology was already defined and deployed. Packet-based networks
have become the common transport for both data and telephony, were traditionally considered unreliable and best effort. As packet-
replacing traditional transport protocols. Consequently, packet-based based networks evolved, they have become the common transport for
networks were expected to provide a similar "carrier grade" both data and telephony, replacing traditional transport protocols.
experience, and specifically to support more advanced OAM functions, Consequently, packet-based networks were expected to provide a
beyond ICMP and router hellos, that were traditionally used for fault similar "carrier grade" experience, and specifically to support more
detection. advanced OAM functions, beyond ICMP and router hellos, that were
traditionally used for fault detection.
As typical networks have a multi-layer architecture, the set of OAM As typical networks have a multi-layer architecture, the set of OAM
protocols similarly take a multi-layer structure; each layer has its protocols similarly take a multi-layer structure; each layer has its
own OAM protocols. Moreover, OAM can be used at different levels of own OAM protocols. Moreover, OAM can be used at different levels of
hierarchy in the network to form a multi-layer OAM solution, as shown hierarchy in the network to form a multi-layer OAM solution, as shown
in the example in Figure 1. in the example in Figure 1.
Figure 1 illustrates a network in which IP traffic between two Figure 1 illustrates a network in which IP traffic between two
customer edges is transported over an MPLS provider network. MPLS OAM customer edges is transported over an MPLS provider network. MPLS
is used at the provider-level for monitoring the connection between OAM is used at the provider level for monitoring the connection
the two provider edges, while IP OAM is used at the customer-level between the two provider edges, while IP OAM is used at the customer
for monitoring the end-to-end connection between the two customer level for monitoring the end-to-end connection between the two
edges. customer edges.
|<-------------- Customer-level OAM -------------->| |<-------------- Customer-level OAM -------------->|
IP OAM (Ping, Traceroute, OWAMP, TWAMP) IP OAM (Ping, Traceroute, OWAMP, TWAMP)
|<- Provider-level OAM ->| |<- Provider-level OAM ->|
MPLS OAM (LSP Ping) MPLS OAM (LSP Ping)
+-----+ +----+ +----+ +-----+ +-----+ +----+ +----+ +-----+
| | | |========================| | | | | | | |========================| | | |
| |-------| | MPLS | |-------| | | |-------| | MPLS | |-------| |
| | IP | | | | IP | | | | IP | | | | IP | |
+-----+ +----+ +----+ +-----+ +-----+ +----+ +----+ +-----+
Customer Provider Provider Customer Customer Provider Provider Customer
Edge Edge Edge Edge Edge Edge Edge Edge
Figure 1 Example: Multi-layer OAM Figure 1: Example of Multi-layer OAM
1.2. Target Audience 1.2. Target Audience
The target audience of this document includes: The target audience of this document includes:
o Standards development organizations - both IETF working groups and o Standards development organizations - Both IETF working groups and
non-IETF organizations can benefit from this document when non-IETF organizations can benefit from this document when
designing new OAM protocols, or when looking to reuse existing OAM designing new OAM protocols, or when looking to reuse existing OAM
tools for new technologies. tools for new technologies.
o Network equipment vendors and network operators - can use this o Network equipment vendors and network operators can use this
document as an index to some of the common IETF OAM tools. document as an index to some of the common IETF OAM tools.
It should be noted that some background in OAM is necessary in order It should be noted that some background in OAM is necessary in order
to understand and benefit from this document. Specifically, the to understand and benefit from this document. Specifically, the
reader is assumed to be familiar with the term OAM [OAM-Def], the reader is assumed to be familiar with the term "OAM" [OAM-Def], the
motivation for using OAM, and the distinction between OAM and network motivation for using OAM, and the distinction between OAM and network
management [OAM-Mng]. management [OAM-Mng].
1.3. OAM-related Work in the IETF 1.3. OAM-Related Work in the IETF
This memo provides an overview of the different sets of OAM tools This memo provides an overview of the different sets of OAM tools
defined by the IETF. The set of OAM tools described in this memo are defined by the IETF. The set of OAM tools described in this memo are
applicable to IP unicast, MPLS, pseudowires, MPLS Transport Profile applicable to IP unicast, MPLS, pseudowires, MPLS Transport Profile
(MPLS-TP), and TRILL. While OAM tools that are applicable to other (MPLS-TP), and TRILL. While OAM tools that are applicable to other
technologies exist, they are beyond the scope of this memo. technologies exist, they are beyond the scope of this memo.
This document focuses on IETF documents that have been published as This document focuses on IETF documents that have been published as
RFCs, while other ongoing OAM-related work is outside the scope. RFCs, while other ongoing OAM-related work is outside the scope.
The IETF has defined OAM protocols and tools in several different The IETF has defined OAM protocols and tools in several different
contexts. We roughly categorize these efforts into a few sets of OAM- contexts. We roughly categorize these efforts into a few sets of
related RFCs, listed in Table 1. Each set defines a logically-coupled OAM-related RFCs, listed in Table 1. Each set defines a logically
set of RFCs, although the sets are in some cases intertwined by coupled set of RFCs, although the sets are in some cases intertwined
common tools and protocols. by common tools and protocols.
The discussion in this document is ordered according to these sets The discussion in this document is ordered according to these sets
(the acronyms and abbreviations are listed in Section 2.1.). (the acronyms and abbreviations are listed in Section 2.1).
+--------------+------------+ +--------------+------------+
| Toolset | Transport | | Toolset | Transport |
| | Technology | | | Technology |
+--------------+------------+ +--------------+------------+
|IP Ping | IPv4/IPv6 | |IP Ping | IPv4/IPv6 |
+--------------+------------+ +--------------+------------+
|IP Traceroute | IPv4/IPv6 | |IP Traceroute | IPv4/IPv6 |
+--------------+------------+ +--------------+------------+
|BFD | generic | |BFD | generic |
+--------------+------------+ +--------------+------------+
|MPLS OAM | MPLS | |MPLS OAM | MPLS |
+--------------+------------+ +--------------+------------+
|MPLS-TP OAM | MPLS-TP | |MPLS-TP OAM | MPLS-TP |
+--------------+------------+ +--------------+------------+
|Pseudowire OAM| Pseudowires| |Pseudowire OAM| Pseudowires|
+--------------+------------+ +--------------+------------+
|OWAMP and | IPv4/IPv6 | |OWAMP and | IPv4/IPv6 |
|TWAMP | | |TWAMP | |
+--------------+------------+ +--------------+------------+
|TRILL OAM | TRILL | |TRILL OAM | TRILL |
+--------------+------------+ +--------------+------------+
Table 1 OAM Toolset Packages in the IETF Documents
Table 1: OAM Toolset Packages in the IETF Documents
This document focuses on OAM tools that have been developed in the This document focuses on OAM tools that have been developed in the
IETF. A short summary of some of the significant OAM standards that IETF. A short summary of some of the significant OAM standards that
have been developed in other standard organizations is presented in have been developed in other standard organizations is presented in
Appendix A.2. Appendix A.2.
1.4. Focusing on the Data Plane 1.4. Focusing on the Data Plane
OAM tools may, and quite often do, work in conjunction with a control OAM tools may, and quite often do, work in conjunction with a control
plane and/or management plane. OAM provides instrumentation tools plane and/or management plane. OAM provides instrumentation tools
for measuring and monitoring the data plane. OAM tools often use for measuring and monitoring the data plane. OAM tools often use
control plane functions, e.g., to initialize OAM sessions and to control-plane functions, e.g., to initialize OAM sessions and to
exchange various parameters. The OAM tools communicate with the exchange various parameters. The OAM tools communicate with the
management plane to raise alarms, and often OAM tools may be management plane to raise alarms, and often OAM tools may be
activated by the management (as well as by the control plane), e.g., activated by the management plane (as well as by the control plane),
to locate and localize problems. e.g., to locate and localize problems.
The considerations of the control plane maintenance tools and the The considerations of the control-plane maintenance tools and the
functionality of the management plane are out of scope for this functionality of the management plane are out of scope for this
document, which concentrates on presenting the data plane tools that document, which concentrates on presenting the data-plane tools that
are used for OAM. Network repair functions such as Fast Reroute (FRR) are used for OAM. Network repair functions such as Fast Reroute
and protection switching, which are often triggered by OAM protocols, (FRR) and protection switching, which are often triggered by OAM
are also out of the scope of this document. protocols, are also out of the scope of this document.
Since OAM protocols are used for monitoring the data plane, it is Since OAM protocols are used for monitoring the data plane, it is
imperative for OAM tools to be capable of testing the actual data imperative for OAM tools to be capable of testing the actual data
plane with as much accuracy as possible. Thus, it is important to plane with as much accuracy as possible. Thus, it is important to
enforce fate-sharing between OAM traffic that monitors the data plane enforce fate-sharing between OAM traffic that monitors the data plane
and the data plane traffic it monitors. and the data-plane traffic it monitors.
2. Terminology 2. Terminology
2.1. Abbreviations 2.1. Abbreviations
ACH Associated Channel Header ACH Associated Channel Header
AIS Alarm Indication Signal AIS Alarm Indication Signal
ATM Asynchronous Transfer Mode ATM Asynchronous Transfer Mode
BFD Bidirectional Forwarding Detection BFD Bidirectional Forwarding Detection
CC Continuity Check CC Continuity Check
CV Connectivity Verification CC-V Continuity Check and Connectivity Verification
DM Delay Measurement CV Connectivity Verification
ECMP Equal Cost Multiple Paths
FEC Forwarding Equivalence Class DM Delay Measurement
FRR Fast Reroute ECMP Equal-Cost Multipath
G-ACh Generic Associated Channel FEC Forwarding Equivalence Class
GAL Generic Associated Label FRR Fast Reroute
ICMP Internet Control Message Protocol G-ACh Generic Associated Channel
L2TP Layer Two Tunneling Protocol GAL Generic Associated Channel Label
L2VPN Layer Two Virtual Private Network ICMP Internet Control Message Protocol
L3VPN Layer Three Virtual Private Network L2TP Layer 2 Tunneling Protocol
LCCE L2TP Control Connection Endpoint L2VPN Layer 2 Virtual Private Network
LDP Label Distribution Protocol L3VPN Layer 3 Virtual Private Network
LER Label Edge Router LCCE L2TP Control Connection Endpoint
LM Loss Measurement LDP Label Distribution Protocol
LER Label Edge Router
LSP Label Switched Path LM Loss Measurement
LSR Label Switched Router LSP Label Switched Path
ME Maintenance Entity LSR Label Switching Router
MEG Maintenance Entity Group ME Maintenance Entity
MEP MEG End Point MEG Maintenance Entity Group
MIP MEG Intermediate Point MEP MEG End Point
MP Maintenance Point MIP MEG Intermediate Point
MPLS Multiprotocol Label Switching MP Maintenance Point
MPLS-TP MPLS Transport Profile MPLS Multiprotocol Label Switching
MTU Maximum Transmission Unit MPLS-TP MPLS Transport Profile
OAM Operations, Administration, and Maintenance MTU Maximum Transmission Unit
OWAMP One-way Active Measurement Protocol
PDH Plesiochronous Digital Hierarchy OAM Operations, Administration, and Maintenance
PE Provider Edge OWAMP One-Way Active Measurement Protocol
PSN Public Switched Network PDH Plesiochronous Digital Hierarchy
PW Pseudowire PE Provider Edge
PWE3 Pseudowire Emulation Edge-to-Edge PSN Public Switched Network
RBridge Routing Bridge PW Pseudowire
RDI Remote Defect Indication PWE3 Pseudowire Emulation Edge-to-Edge
SDH Synchronous Digital Hierarchy RBridge Routing Bridge
SONET Synchronous Optical Networking RDI Remote Defect Indication
TRILL Transparent Interconnection of Lots of Links SDH Synchronous Digital Hierarchy
TTL Time To Live SONET Synchronous Optical Network
TWAMP Two-way Active Measurement Protocol TRILL Transparent Interconnection of Lots of Links
TTL Time To Live
VCCV Virtual Circuit Connectivity Verification TWAMP Two-Way Active Measurement Protocol
VPN Virtual Private Network VCCV Virtual Circuit Connectivity Verification
2.2. Terminology used in OAM Standards VPN Virtual Private Network
2.2.1. General Terms 2.2. Terminology Used in OAM Standards
A wide variety of terms is used in various OAM standards. This 2.2.1. General Terms
A wide variety of terms is used in various OAM standards. This
section presents a comparison of the terms used in various OAM section presents a comparison of the terms used in various OAM
standards, without fully quoting the definition of each term. standards, without fully quoting the definition of each term.
An interesting overview of the term OAM and its derivatives is An interesting overview of the term "OAM" and its derivatives is
presented in [OAM-Def]. A thesaurus of terminology for MPLS-TP terms presented in [OAM-Def]. A thesaurus of terminology for MPLS-TP terms
is presented in [TP-Term], and provides a good summary of some of the is presented in [TP-Term], which provides a good summary of some of
OAM related terminology. the OAM-related terminology.
2.2.2. Operations, Administration and Maintenance 2.2.2. Operations, Administration, and Maintenance
The following definition of OAM is quoted from [OAM-Def]: The following definition of OAM is quoted from [OAM-Def]:
The components of the "OAM" acronym (and provisioning) are defined as The components of the "OAM" acronym (and provisioning) are defined as
follows: follows:
o Operations - Operation activities are undertaken to keep the o Operations - Operation activities are undertaken to keep the
network (and the services that the network provides) up and network (and the services that the network provides) up and
running. It includes monitoring the network and finding problems. running. It includes monitoring the network and finding problems.
Ideally these problems should be found before users are affected. Ideally these problems should be found before users are affected.
o Administration - Administration activities involve keeping track o Administration - Administration activities involve keeping track
of resources in the network and how they are used. It includes of resources in the network and how they are used. It includes
all the bookkeeping that is necessary to track networking all the bookkeeping that is necessary to track networking
resources and the network under control. resources and the network under control.
o Maintenance - Maintenance activities are focused on facilitating o Maintenance - Maintenance activities are focused on facilitating
repairs and upgrades -- for example, when equipment must be repairs and upgrades -- for example, when equipment must be
replaced, when a router needs a patch for an operating system replaced, when a router needs a patch for an operating system
image, or when a new switch is added to a network. Maintenance image, or when a new switch is added to a network. Maintenance
also involves corrective and preventive measures to make the also involves corrective and preventive measures to make the
managed network run more effectively, e.g., adjusting device managed network run more effectively, e.g., adjusting device
configuration and parameters. configuration and parameters.
2.2.3. Functions, Tools and Protocols 2.2.3. Functions, Tools, and Protocols
OAM Function OAM Function
An OAM function is an instrumentation measurement type or diagnostic. An OAM function is an instrumentation measurement type or
diagnostic.
OAM functions are the atomic building blocks of OAM, where each OAM functions are the atomic building blocks of OAM, where each
function defines an OAM capability. function defines an OAM capability.
Typical examples of OAM functions are presented in Section 3. Typical examples of OAM functions are presented in Section 3.
OAM Protocol OAM Protocol
A protocol used for implementing one or more OAM functions. An OAM protocol is a protocol used for implementing one or more
OAM functions.
The OWAMP-Test [OWAMP] is an example of an OAM protocol. The OWAMP-Test [OWAMP] is an example of an OAM protocol.
OAM Tool OAM Tool
An OAM tool is a specific means of applying one or more OAM An OAM tool is a specific means of applying one or more OAM
functions. functions.
In some cases an OAM protocol *is* an OAM tool, e.g., OWAMP-Test. In In some cases, an OAM protocol *is* an OAM tool, e.g., OWAMP-Test.
other cases an OAM tool uses a set of protocols that are not strictly In other cases, an OAM tool uses a set of protocols that are not
OAM-related; for example, Traceroute (Section 4.2.) can be strictly OAM related; for example, Traceroute (Section 4.2) can be
implemented using UDP and ICMP messages, without using an OAM implemented using UDP and ICMP messages, without using an OAM
protocol per se. protocol per se.
2.2.4. Data Plane, Control Plane and Management Plane 2.2.4. Data Plane, Control Plane, and Management Plane
Data Plane Data Plane
The data plane is the set of functions used to transfer data in the The data plane is the set of functions used to transfer data in
stratum or layer under consideration [ITU-Terms]. the stratum or layer under consideration [ITU-Terms].
The Data Plane is also known as the Forwarding Plane or the User The data plane is also known as the forwarding plane or the user
Plane. plane.
Control Plane Control Plane
The control plane is the set of protocols and mechanisms that enable The control plane is the set of protocols and mechanisms that
routers to efficiently learn how to forward packets towards their enable routers to efficiently learn how to forward packets towards
final destination (based on [Comp]). their final destination (based on [Comp]).
Management Plane Management Plane
The term Management Plane, as described in [Mng], is used to describe The term "Management Plane", as described in [Mng], is used to
the exchange of management messages through management protocols describe the exchange of management messages through management
(often transported by IP and by IP transport protocols) between protocols (often transported by IP and by IP transport protocols)
management applications and the managed entities such as network between management applications and the managed entities such as
nodes. network nodes.
Data Plane vs. Control Plane vs. Management Plane Data Plane vs. Control Plane vs. Management Plane
The distinction between the planes is at times a bit vague. For The distinction between the planes is at times a bit vague. For
example, the definition of "Control Plane" above may imply that OAM example, the definition of "Control Plane" above may imply that
tools such as ping, BFD and others are in fact in the control plane. OAM tools such as ping, BFD, and others are in fact in the control
plane.
This document focuses on tools used for monitoring the data plane. This document focuses on tools used for monitoring the data plane.
While these tools could arguably be considered to be in the control While these tools could arguably be considered to be in the
plane, these tools monitor the data plane, and hence it is imperative control plane, these tools monitor the data plane, and hence it is
to have fate-sharing between OAM traffic that monitors the data plane imperative to have fate-sharing between OAM traffic that monitors
and the data plane traffic it monitors. the data plane and the data-plane traffic it monitors.
Another potentially vague distinction is between the management plane Another potentially vague distinction is between the management
and control plane. The management plane should be seen as separate plane and control plane. The management plane should be seen as
from, but possibly overlapping with, the control plane (based on separate from, but possibly overlapping with, the control plane
[Mng]). (based on [Mng]).
2.2.5. The Players 2.2.5. The Players
An OAM tool is used between two (or more) peers. Various terms are An OAM tool is used between two (or more) peers. Various terms are
used in IETF documents to refer to the players that take part in OAM. used in IETF documents to refer to the players that take part in OAM.
Table 2 summarizes the terms used in each of the toolsets discussed Table 2 summarizes the terms used in each of the toolsets discussed
in this document. in this document.
+--------------------------+--------------------------+ +--------------------------+---------------------------+
| Toolset | Terms | | Toolset | Terms |
+--------------------------+--------------------------+ +--------------------------+---------------------------+
| Ping / Traceroute |-Host | | Ping / Traceroute |- Host |
| ([ICMPv4], [ICMPv6], |-Node | | ([ICMPv4], [ICMPv6], |- Node |
| [TCPIP-Tools]) |-Interface | | [TCPIP-Tools]) |- Interface |
| |-Gateway | | |- Gateway |
+ ------------------------ + ------------------------ + + ------------------------ + ------------------------- +
| BFD [BFD] | System | | BFD [BFD] |- System |
+ ------------------------ + ------------------------ + + ------------------------ + ------------------------- +
| MPLS OAM [MPLS-OAM-FW] | LSR | | MPLS OAM [MPLS-OAM-FW] |- LSR |
+ ------------------------ + ------------------------ + + ------------------------ + ------------------------- +
| MPLS-TP OAM [TP-OAM-FW] |-End Point - MEP | | MPLS-TP OAM [TP-OAM-FW] |- End Point - MEP |
| |-Intermediate Point - MIP | | |- Intermediate Point - MIP |
+ ------------------------ + ------------------------ + + ------------------------ + ------------------------- +
| Pseudowire OAM [VCCV] |-PE | | Pseudowire OAM [VCCV] |- PE |
| |-LCCE | | |- LCCE |
+ ------------------------ + ------------------------ + + ------------------------ + ------------------------- +
| OWAMP and TWAMP |-Host | | OWAMP and TWAMP |- Host |
| ([OWAMP], [TWAMP]) |-End system | | ([OWAMP], [TWAMP]) |- End system |
+ ------------------------ + ------------------------ + + ------------------------ + ------------------------- +
| TRILL OAM [TRILL-OAM] |-RBridge | | TRILL OAM [TRILL-OAM] |- RBridge |
+--------------------------+--------------------------+ +--------------------------+---------------------------+
Table 2 Maintenance Point Terminology
2.2.6. Proactive and On-demand Activation Table 2: Maintenance Point Terminology
2.2.6. Proactive and On-Demand Activation
The different OAM tools may be used in one of two basic types of The different OAM tools may be used in one of two basic types of
activation: activation:
Proactive Proactive
Proactive activation - indicates that the tool is activated on a
continual basis, where messages are sent periodically, and errors are
detected when a certain number of expected messages are not received.
On-demand Proactive activation - indicates that the tool is activated on a
continual basis, where messages are sent periodically, and errors
are detected when a certain number of expected messages are not
received.
On-demand activation - indicates that the tool is activated On-demand
"manually" to detect a specific anomaly.
2.2.7. Connectivity Verification and Continuity Checks On-demand activation - indicates that the tool is activated
"manually" to detect a specific anomaly.
2.2.7. Connectivity Verification and Continuity Checks
Two distinct classes of failure management functions are used in OAM Two distinct classes of failure management functions are used in OAM
protocols, connectivity verification and continuity checks. The protocols: Connectivity Verification and Continuity Checks. The
distinction between these terms is defined in [MPLS-TP-OAM], and is distinction between these terms is defined in [MPLS-TP-OAM] and is
used similarly in this document. used similarly in this document.
Continuity Check Continuity Check
Continuity checks are used to verify that a destination is reachable, Continuity Checks are used to verify that a destination is
and are typically sent proactively, though they can be invoked on- reachable, and are typically sent proactively, though they can be
demand as well. invoked on-demand as well.
Connectivity Verification Connectivity Verification
A connectivity verification function allows Alice to check whether A Connectivity Verification function allows Alice to check whether
she is connected to Bob or not. It is noted that while the CV she is connected to Bob or not. It is noted that while the CV
function is performed in the data plane, the "expected path" is function is performed in the data plane, the "expected path" is
predetermined either in the control plane or in the management plane. predetermined in either the control plane or the management plane.
A connectivity verification (CV) protocol typically uses a CV A Connectivity Verification (CV) protocol typically uses a CV
message, followed by a CV reply that is sent back to the originator. message, followed by a CV reply that is sent back to the
A CV function can be applied proactively or on-demand. originator. A CV function can be applied proactively or
on-demand.
Connectivity verification tools often perform path verification as Connectivity Verification tools often perform path verification as
well, allowing Alice to verify that messages from Bob are received well, allowing Alice to verify that messages from Bob are received
through the correct path, thereby verifying not only that the two MPs through the correct path, thereby verifying not only that the two
are connected, but also that they are connected through the expected MPs are connected, but also that they are connected through the
path, allowing detection of unexpected topology changes. expected path, allowing detection of unexpected topology changes.
Connectivity verification functions can also be used for checking the Connectivity Verification functions can also be used for checking
MTU of the path between the two peers. the MTU of the path between the two peers.
Connectivity verification and continuity checks are considered Connectivity Verification and Continuity Checks are considered
complementary mechanisms, and are often used in conjunction with each complementary mechanisms and are often used in conjunction with
other. each other.
2.2.8. Connection Oriented vs. Connectionless Communication 2.2.8. Connection-Oriented vs. Connectionless Communication
Connection Oriented Connection-Oriented
In Connection Oriented technologies an end-to-end connection is In connection-oriented technologies, an end-to-end connection is
established (by a control protocol or provisioned by a management established (by a control protocol or provisioned by a management
system) prior to the transmission of data. system) prior to the transmission of data.
Typically a connection identifier is used to identify the connection. Typically a connection identifier is used to identify the
In connection oriented technologies it is often the case (although connection. In connection-oriented technologies, it is often the
not always) that all packets belonging to a specific connection use case (although not always) that all packets belonging to a
the same route through the network. specific connection use the same route through the network.
Connectionless Connectionless
In Connectionless technologies data is typically sent between end In connectionless technologies, data is typically sent between end
points without prior arrangement. Packets are routed independently points without prior arrangement. Packets are routed
based on their destination address, and hence different packets may independently based on their destination address, and hence
be routed in a different way across the network. different packets may be routed in a different way across the
network.
Discussion Discussion
The OAM tools described in this document include tools that support The OAM tools described in this document include tools that
connection oriented technologies, as well as tools for connectionless support connection-oriented technologies, as well as tools for
technologies. connectionless technologies.
In connection oriented technologies OAM is used to monitor a In connection-oriented technologies, OAM is used to monitor a
*specific* connection; OAM packets are forwarded through the same *specific* connection; OAM packets are forwarded through the same
route as the data traffic and receive the same treatment. In route as the data traffic and receive the same treatment. In
connectionless technologies, OAM is used between a source and connectionless technologies, OAM is used between a source and
destination pair without defining a specific connection. Moreover, in destination pair without defining a specific connection.
some cases the route of OAM packets may differ from the one of the Moreover, in some cases, the route of OAM packets may differ from
data traffic. For example, the connectionless IP Ping (Section 4.1.) the one of the data traffic. For example, the connectionless IP
tests the reachability from a source to a given destination, while Ping (Section 4.1) tests the reachability from a source to a given
the connection oriented LSP Ping (Section 4.4.) is used for destination, while the connection-oriented LSP Ping (Section
monitoring a specific LSP (connection), and provides the capability 4.4.1) is used for monitoring a specific LSP (connection) and
to monitor all the available paths used by an LSP. provides the capability to monitor all the available paths used by
an LSP.
It should be noted that in some cases connectionless protocols are It should be noted that in some cases connectionless protocols are
monitored by connection oriented OAM protocols. For example, while IP monitored by connection-oriented OAM protocols. For example,
is a connectionless protocol, it can monitored by BFD (Section 4.3. while IP is a connectionless protocol, it can be monitored by BFD
), which is connection oriented. (Section 4.3), which is connection oriented.
2.2.9. Point-to-point vs. Point-to-multipoint Services 2.2.9. Point-to-Point vs. Point-to-Multipoint Services
Point-to-point (P2P) Point-to-point (P2P)
A P2P service delivers data from a single source to a single
destination.
Point-to-multipoint (P2MP) A P2P service delivers data from a single source to a single
destination.
A P2MP service delivers data from a single source to a one or more Point-to-multipoint (P2MP)
destinations (based on [Signal]).
An MP2MP service is a service that delivers data from more than one A P2MP service delivers data from a single source to a one or more
source to one or more receivers (based on [Signal]). destinations (based on [Signal]).
Note: the two definitions for P2MP and MP2MP are quoted from An MP2MP service is a service that delivers data from more than
[Signal]. Although [Signal] describes a specific case of P2MP and one source to one or more receivers (based on [Signal]).
MP2MP which is MPLS-specific, these two definitions also apply to
non-MPLS cases.
Discussion Note: the two definitions for P2MP and MP2MP are quoted from
[Signal]. Although [Signal] describes a specific case of P2MP and
MP2MP that is MPLS-specific, these two definitions also apply to
non-MPLS cases.
The OAM tools described in this document include tools for P2P Discussion
services, as well as tools for P2MP services.
The distinction between P2P services and P2MP services affects the The OAM tools described in this document include tools for P2P
corresponding OAM tools. A P2P service is typically simpler to services, as well as tools for P2MP services.
monitor, as it consists of a single pair of end points. P2MP and
MP2MP services present several challenges. For example, in a P2MP
service, the OAM mechanism not only verifies that each of the
destinations is reachable from the source, but also verifies that the
P2MP distribution tree is intact and loop-free.
2.2.10. Failures The distinction between P2P services and P2MP services affects the
corresponding OAM tools. A P2P service is typically simpler to
monitor, as it consists of a single pair of endpoints. P2MP and
MP2MP services present several challenges. For example, in a P2MP
service, the OAM mechanism not only verifies that each of the
destinations is reachable from the source but also verifies that
the P2MP distribution tree is intact and loop-free.
The terms Failure, Fault, and Defect are used interchangeably in the 2.2.10. Failures
standards, referring to a malfunction that can be detected by a
connectivity or a continuity check. In some standards, such as The terms "Failure", "Fault", and "Defect" are used interchangeably
802.1ag [IEEE802.1Q] , there is no distinction between these terms, in the standards, referring to a malfunction that can be detected by
while in other standards each of these terms refers to a different a Connectivity Verification or a Continuity Check. In some
type of malfunction. standards, such as 802.1ag [IEEE802.1Q], there is no distinction
between these terms, while in other standards each of these terms
refers to a different type of malfunction.
The terminology used in IETF MPLS-TP OAM is based on the ITU-T The terminology used in IETF MPLS-TP OAM is based on the ITU-T
terminology, which distinguishes between these three terms in terminology, which distinguishes between these three terms in
[ITU-T-G.806]; [ITU-T-G.806] as follows:
Fault Fault
The term Fault refers to an inability to perform a required action, The term "Fault" refers to an inability to perform a required action,
e.g., an unsuccessful attempt to deliver a packet. e.g., an unsuccessful attempt to deliver a packet.
Defect Defect
The term Defect refers to an interruption in the normal operation, The term "Defect" refers to an interruption in the normal operation,
such as a consecutive period of time where no packets are delivered such as a consecutive period of time where no packets are delivered
successfully. successfully.
Failure Failure
The term Failure refers to the termination of the required function. The term "Failure" refers to the termination of the required
While a Defect typically refers to a limited period of time, a function. While a Defect typically refers to a limited period of
failure refers to a long period of time. time, a failure refers to a long period of time.
3. OAM Functions 3. OAM Functions
This subsection provides a brief summary of the common OAM functions This subsection provides a brief summary of the common OAM functions
used in OAM-related standards. These functions are used as building used in OAM-related standards. These functions are used as building
blocks in the OAM standards described in this document. blocks in the OAM standards described in this document.
o Connectivity Verification (CV), Path Verification and Continuity o Connectivity Verification (CV), Path Verification, and Continuity
Checks (CC): Check (CC):
As defined in Section 2.2.7. As defined in Section 2.2.7.
o Path Discovery / Fault Localization: o Path Discovery / Fault Localization:
This function can be used to trace the route to a destination, This function can be used to trace the route to a destination,
i.e., to identify the nodes along the route to the destination. i.e., to identify the nodes along the route to the destination.
When more than one route is available to a specific destination, When more than one route is available to a specific destination,
this function traces one of the available routes. When a failure this function traces one of the available routes. When a failure
occurs, this function attempts to detect the location of the occurs, this function attempts to detect the location of the
failure. failure.
Note that the term route tracing (or Traceroute) that is used in Note that the term "route tracing" (or "Traceroute"), which is
the context of IP and MPLS, is sometimes referred to as path used in the context of IP and MPLS, is sometimes referred to as
tracing in the context of other protocols, such as TRILL. "path tracing" in the context of other protocols, such as TRILL.
o Performance Monitoring: o Performance Monitoring:
Typically refers to: Typically refers to:
o Loss Measurement (LM) - monitors the packet loss rate. * Loss Measurement (LM) - monitors the packet loss rate.
o Delay Measurement (DM) - monitors the delay and delay * Delay Measurement (DM) - monitors the delay and delay variation
variation (jitter). (jitter).
4. OAM Tools in the IETF - a Detailed Description 4. OAM Tools in the IETF - A Detailed Description
This section presents a detailed description of the sets of OAM- This section presents a detailed description of the sets of OAM-
related tools in each of the toolsets in Table 1. related tools in each of the toolsets in Table 1.
4.1. IP Ping 4.1. IP Ping
Ping is a common network diagnosis application for IP networks that Ping is a common network diagnostic application for IP networks that
uses ICMP. According to [NetTerms], 'Ping' is an abbreviation for use ICMP. According to [NetTerms], 'Ping' is an abbreviation for
Packet internet groper, although the term has been so commonly used Packet internet groper, although the term has been so commonly used
that it stands on its own. As defined in [NetTerms], it is a program that it stands on its own. As defined in [NetTerms], it is a program
used to test reachability of destinations by sending them an ICMP used to test reachability of destinations by sending them an ICMP
echo request and waiting for a reply. Echo request and waiting for a reply.
The ICMP Echo request/reply exchange in Ping is used as a continuity The ICMP Echo request/reply exchange in Ping is used as a Continuity
check function for the Internet Protocol. The originator transmits an Check function for the Internet Protocol. The originator transmits
ICMP Echo request packet, and the receiver replies with an Echo an ICMP Echo request packet, and the receiver replies with an Echo
reply. ICMP ping is defined in two variants, [ICMPv4] is used for reply. ICMP Ping is defined in two variants: [ICMPv4] is used for
IPv4, and [ICMPv6] is used for IPv6. IPv4, and [ICMPv6] is used for IPv6.
Ping can be invoked either to a unicast destination or to a multicast Ping can be invoked to either a unicast destination or a multicast
destination. In the latter case, all members of the multicast group destination. In the latter case, all members of the multicast group
send an Echo reply back to the originator. send an Echo reply back to the originator.
Ping implementations typically use ICMP messages. UDP Ping is a Ping implementations typically use ICMP messages. UDP Ping is a
variant that uses UDP messages instead of ICMP echo messages. variant that uses UDP messages instead of ICMP Echo messages.
Ping is a single-ended continuity check, i.e., it allows the Ping is a single-ended Continuity Check, i.e., it allows the
*initiator* of the Echo request to test the reachability. If it is *initiator* of the Echo request to test the reachability. If it is
desirable for both ends to test the reachability, both ends have to desirable for both ends to test the reachability, both ends have to
invoke Ping independently. invoke Ping independently.
Note that since ICMP filtering is deployed in some routers and Note that since ICMP filtering is deployed in some routers and
firewalls, the usefulness of Ping is sometimes limited in the wider firewalls, the usefulness of Ping is sometimes limited in the wider
internet. This limitation is equally relevant to Traceroute. Internet. This limitation is equally relevant to Traceroute.
4.2. IP Traceroute 4.2. IP Traceroute
Traceroute ([TCPIP-Tools], [NetTools]) is an application that allows Traceroute ([TCPIP-Tools], [NetTools]) is an application that allows
users to discover a path between an IP source and an IP destination. users to discover a path between an IP source and an IP destination.
The most common way to implement Traceroute [TCPIP-Tools] is The most common way to implement Traceroute [TCPIP-Tools] is
described as follows. Traceroute sends a sequence of UDP packets to described as follows. Traceroute sends a sequence of UDP packets to
UDP port 33434 at the destination. By default, Traceroute begins by UDP port 33434 at the destination. By default, Traceroute begins by
sending three packets (the number of packets is configurable in most sending three packets (the number of packets is configurable in most
Traceroute implementations), each with an IP Time-To-Live (or Hop Traceroute implementations), each with an IP Time-To-Live (or Hop
Limit in IPv6) value of one to the destination. These packets expire Limit in IPv6) value of one, to the destination. These packets
as soon as they reach the first router in the path. Consequently, expire as soon as they reach the first router in the path.
that router sends three ICMP Time Exceeded Messages back to the Consequently, that router sends three ICMP Time Exceeded Messages
Traceroute application. Traceroute now sends another three UDP back to the Traceroute application. Traceroute now sends another
packets, each with the TTL value of 2. These messages cause the three UDP packets, each with the TTL value of 2. These messages
second router to return ICMP messages. This process continues, with cause the second router to return ICMP messages. This process
ever increasing values for the TTL field, until the packets actually continues, with ever-increasing values for the TTL field, until the
reach the destination. Because no application listens to port 33434 packets actually reach the destination. Because no application
at the destination, the destination returns ICMP Destination listens to port 33434 at the destination, the destination returns
Unreachable Messages indicating an unreachable port. This event ICMP Destination Unreachable Messages indicating an unreachable port.
indicates to the Traceroute application that it is finished. The This event indicates to the Traceroute application that it is
Traceroute program displays the round-trip delay associated with each finished. The Traceroute program displays the round-trip delay
of the attempts. associated with each of the attempts.
While Traceroute is a tool that finds *a* path from A to B, it should While Traceroute is a tool that finds *a* path from A to B, it should
be noted that traffic from A to B is often forwarded through Equal be noted that traffic from A to B is often forwarded through Equal-
Cost Multiple Paths (ECMP). Paris Traceroute [PARIS] is an extension Cost Multipaths (ECMPs). Paris Traceroute [PARIS] is an extension to
to Traceroute that attempts to discovers all the available paths from Traceroute that attempts to discovers all the available paths from A
A to B by scanning different values of header fields (such as UDP to B by scanning different values of header fields (such as UDP
ports) in the probe packets. ports) in the probe packets.
It is noted that Traceroute is an application, and not a protocol. As It is noted that Traceroute is an application, and not a protocol.
such, it has various different implementations. One of the most As such, it has various different implementations. One of the most
common ones uses UDP probe packets, as described above. Other common ones uses UDP probe packets, as described above. Other
implementations exist that use other types of probe messages, such as implementations exist that use other types of probe messages, such as
ICMP or TCP. ICMP or TCP.
Note that IP routing may be asymmetric. While Traceroute discovers a Note that IP routing may be asymmetric. While Traceroute discovers a
path between a source and destination, it does not reveal the reverse path between a source and destination, it does not reveal the reverse
path. path.
A few ICMP extensions ([ICMP-MP], [ICMP-Int]) have been defined in A few ICMP extensions ([ICMP-MP], [ICMP-Int]) have been defined in
the context of Traceroute. These documents define several extensions, the context of Traceroute. These documents define several
including extensions to the ICMP Destination Unreachable message, extensions, including extensions to the ICMP Destination Unreachable
that can be used by Traceroute applications. message, that can be used by Traceroute applications.
Traceroute allows path discovery to *unicast* destination addresses. Traceroute allows path discovery to *unicast* destination addresses.
A similar tool [mtrace] was defined for multicast destination A similar tool [mtrace] was defined for multicast destination
addresses, allowing to trace the route that a multicast IP packet addresses; it allows tracing the route that a multicast IP packet
takes from a source to a particular receiver. takes from a source to a particular receiver.
4.3. Bidirectional Forwarding Detection (BFD) 4.3. Bidirectional Forwarding Detection (BFD)
4.3.1. Overview 4.3.1. Overview
While multiple OAM tools have been defined for various protocols in While multiple OAM tools have been defined for various protocols in
the protocol stack, Bidirectional Forwarding Detection [BFD], defined the protocol stack, Bidirectional Forwarding Detection [BFD], defined
by the IETF BFD working group, is a generic OAM tool that can be by the IETF BFD working group, is a generic OAM tool that can be
deployed over various encapsulating protocols, and in various medium deployed over various encapsulating protocols, and in various medium
types. The IETF has defined variants of the protocol for IP ([BFD- types. The IETF has defined variants of the protocol for IP
IP], [BFD-Multi]), for MPLS LSPs [BFD-LSP], and for pseudowires [BFD- ([BFD-IP], [BFD-Multi]), for MPLS LSPs [BFD-LSP], and for pseudowires
VCCV]. The usage of BFD in MPLS-TP is defined in [TP-CC-CV]. [BFD-VCCV]. The usage of BFD in MPLS-TP is defined in [TP-CC-CV].
BFD includes two main OAM functions, using two types of BFD packets: BFD includes two main OAM functions, using two types of BFD packets:
BFD Control packets, and BFD Echo packets. BFD Control packets and BFD Echo packets.
4.3.2. Terminology 4.3.2. Terminology
BFD operates between *systems*. The BFD protocol is run between two BFD operates between *systems*. The BFD protocol is run between two
or more systems after establishing a *session*. or more systems after establishing a *session*.
4.3.3. BFD Control 4.3.3. BFD Control
BFD supports a bidirectional continuity check, using BFD control BFD supports a bidirectional Continuity Check, using BFD Control
packets, that are exchanged within a BFD session. BFD sessions packets that are exchanged within a BFD session. BFD sessions
operate in one of two modes: operate in one of two modes:
o Asynchronous mode (i.e., proactive): in this mode BFD control o Asynchronous mode (i.e., proactive): in this mode, BFD Control
packets are sent periodically. When the receiver detects that no packets are sent periodically. When the receiver detects that no
BFD control packets have been received during a predetermined BFD Control packets have been received during a predetermined
period of time, a failure is reported. period of time, a failure is reported.
o Demand mode: in this mode, BFD control packets are sent on-demand. o Demand mode: in this mode, BFD Control packets are sent on demand.
Upon need, a system initiates a series of BFD control packets to Upon need, a system initiates a series of BFD Control packets to
check the continuity of the session. BFD control packets are sent check the continuity of the session. BFD Control packets are sent
independently in each direction. independently in each direction.
Each of the end-points (referred to as systems) of the monitored path Each of the endpoints (referred to as systems) of the monitored path
maintains its own session identification, called a Discriminator, maintains its own session identification, called a Discriminator;
both of which are included in the BFD Control Packets that are both Discriminators are included in the BFD Control Packets that are
exchanged between the end-points. At the time of session exchanged between the endpoints. At the time of session
establishment, the Discriminators are exchanged between the two-end establishment, the Discriminators are exchanged between the two
points. In addition, the transmission (and reception) rate is endpoints. In addition, the transmission (and reception) rate is
negotiated between the two end-points, based on information included negotiated between the two endpoints, based on information included
in the control packets. These transmission rates may be renegotiated in the control packets. These transmission rates may be renegotiated
during the session. during the session.
During normal operation of the session, i.e., when no failures have During normal operation of the session, i.e., when no failures have
been detected, the BFD session is in the Up state. If no BFD Control been detected, the BFD session is in the Up state. If no BFD Control
packets are received during a period of time called the Detection packets are received during a period of time called the Detection
Time, the session is declared to be Down. The detection time is a Time, the session is declared to be Down. The detection time is a
function of the pre-configured or negotiated transmission rate, and a function of the pre-configured or negotiated transmission rate and a
parameter called Detect Mult. Detect Mult determines the number of parameter called Detect Mult. Detect Mult determines the number of
missing BFD Control packets that cause the session to be declared as missing BFD Control packets that cause the session to be declared as
Down. This parameter is included in the BFD Control packet. Down. This parameter is included in the BFD Control packet.
4.3.4. BFD Echo 4.3.4. BFD Echo
A BFD echo packet is sent to a peer system, and is looped back to the A BFD Echo packet is sent to a peer system and is looped back to the
originator. The echo function can be used proactively, or on-demand. originator. The echo function can be used proactively or on demand.
The BFD echo function has been defined in BFD for IPv4 and IPv6 The BFD Echo function has been defined in BFD for IPv4 and IPv6
([BFD-IP]), but is not used in BFD for MPLS LSPs, PWs, or in BFD for ([BFD-IP]), but it is not used in BFD for MPLS LSPs or PWs, or in BFD
MPLS-TP. for MPLS-TP.
4.4. MPLS OAM 4.4. MPLS OAM
The IETF MPLS working group has defined OAM for MPLS LSPs. The The IETF MPLS working group has defined OAM for MPLS LSPs. The
requirements and framework of this effort are defined in requirements and framework of this effort are defined in
[MPLS-OAM-FW] and [MPLS-OAM], respectively. The corresponding OAM [MPLS-OAM-FW] and [MPLS-OAM], respectively. The corresponding OAM
tool defined, in this context, is LSP Ping [LSP-Ping]. OAM for P2MP tool defined, in this context, is LSP Ping [LSP-Ping]. OAM for P2MP
services is defined in [MPLS-P2MP]. services is defined in [MPLS-P2MP].
BFD for MPLS [BFD-LSP] is an alternative means for detecting data- BFD for MPLS [BFD-LSP] is an alternative means for detecting data-
plane failures, as described below. plane failures, as described below.
4.4.1. LSP Ping 4.4.1. LSP Ping
LSP Ping is modeled after the Ping/Traceroute paradigm and thus it LSP Ping is modeled after the Ping/Traceroute paradigm, and thus it
may be used in one of two modes: may be used in one of two modes:
o "Ping" mode: In this mode LSP Ping is used for end-to-end o "Ping" mode: In this mode, LSP Ping is used for end-to-end
connectivity verification between two LERs. Connectivity Verification between two LERs.
o "Traceroute" mode: This mode is used for hop-by-hop fault o "Traceroute" mode: This mode is used for hop-by-hop fault
isolation. isolation.
LSP Ping is based on ICMP Ping operation (of data-plane connectivity LSP Ping is based on the ICMP Ping operation (of data-plane
verification) with additional functionality to verify data-plane vs. Connectivity Verification) with additional functionality to verify
control-plane consistency for a Forwarding Equivalence Class (FEC) data-plane vs. control-plane consistency for a Forwarding Equivalence
and also identify Maximum Transmission Unit (MTU) problems. Class (FEC) and also to identify Maximum Transmission Unit (MTU)
problems.
The Traceroute functionality may be used to isolate and localize MPLS The Traceroute functionality may be used to isolate and localize MPLS
faults, using the Time-to-live (TTL) indicator to incrementally faults, using the Time-To-Live (TTL) indicator to incrementally
identify the sub-path of the LSP that is successfully traversed identify the sub-path of the LSP that is successfully traversed
before the faulty link or node. before the faulty link or node.
The challenge in MPLS networks is that the traffic of a given LSP may The challenge in MPLS networks is that the traffic of a given LSP may
be load balanced across Equal Cost Multiple paths (ECMP). LSP Ping be load-balanced across Equal-Cost Multipaths (ECMPs). LSP Ping
monitors all the available paths of an LSP by monitoring its monitors all the available paths of an LSP by monitoring its
different Forwarding Equivalence Classes (FEC). Note that MPLS-TP different FECs. Note that MPLS-TP does not use ECMP, and thus does
does not use ECMP, and thus does not require OAM over multiple paths. not require OAM over multiple paths.
Another challenge is that an MPLS LSP does not necessarily have a Another challenge is that an MPLS LSP does not necessarily have a
return path; traffic that is sent back from the egress LSR to the return path; traffic that is sent back from the egress LSR to the
ingress LSR is not necessarily sent over an MPLS LSP, but can be sent ingress LSR is not necessarily sent over an MPLS LSP, but it can be
through a different route, such as an IP route. Thus, responding to sent through a different route, such as an IP route. Thus,
an LSP Ping message is not necessarily as trivial as in IP Ping, responding to an LSP Ping message is not necessarily as trivial as in
where the responder just swaps the source and destination IP IP Ping, where the responder just swaps the source and destination IP
addresses. Note that this challenge is not applicable to MPLS-TP, addresses. Note that this challenge is not applicable to MPLS-TP,
where a return path is always available. where a return path is always available.
It should be noted that LSP Ping supports unique identification of It should be noted that LSP Ping supports unique identification of
the LSP within an addressing domain. The identification is checked the LSP within an addressing domain. The identification is checked
using the full FEC identification. LSP Ping is extensible to include using the full FEC identification. LSP Ping is extensible to include
additional information needed to support new functionality, by use of additional information needed to support new functionality, by use of
Type-Length-Value (TLV) constructs. The usage of TLVs is typically Type-Length-Value (TLV) constructs. The usage of TLVs is typically
handled by the control plane, as it is not easy to implement in handled by the control plane, as it is not easy to implement in
hardware. hardware.
LSP Ping supports both asynchronous, as well as, on-demand LSP Ping supports both asynchronous and on-demand activation.
activation.
4.4.2. BFD for MPLS 4.4.2. BFD for MPLS
BFD [BFD-LSP] can be used to detect MPLS LSP data plane failures. BFD [BFD-LSP] can be used to detect MPLS LSP data-plane failures.
A BFD session is established for each MPLS LSP that is being A BFD session is established for each MPLS LSP that is being
monitored. BFD Control packets must be sent along the same path as monitored. BFD Control packets must be sent along the same path as
the monitored LSP. If the LSP is associated with multiple FECs, a BFD the monitored LSP. If the LSP is associated with multiple FECs, a
session is established for each FEC. BFD session is established for each FEC.
While LSP Ping can be used for detecting MPLS data plane failures and While LSP Ping can be used for detecting MPLS data-plane failures and
for verifying the MPLS LSP data plane against the control plane, BFD for verifying the MPLS LSP data plane against the control plane, BFD
can only be used for the former. BFD can be used in conjunction with can only be used for the former. BFD can be used in conjunction with
LSP Ping, as is the case in MPLS-TP (see Section 4.5.4.). LSP Ping, as is the case in MPLS-TP (see Section 4.5.4).
4.4.3. OAM for Virtual Private Networks (VPN) over MPLS 4.4.3. OAM for Virtual Private Networks (VPNs) over MPLS
The IETF has defined two classes of VPNs, Layer 2 VPNs (L2VPN) and The IETF has defined two classes of VPNs: Layer 2 VPNs (L2VPNs) and
Layer 3 VPNs (L3VPN). [L2VPN-OAM] provides the requirements and Layer 3 VPNs (L3VPNs). [L2VPN-OAM] provides the requirements and
framework for OAM in the context of Layer 2 Virtual Private Networks framework for OAM in the context of L2VPNs, and specifically it also
(L2VPN), and specifically it also defines the OAM layering of L2VPNs defines the OAM layering of L2VPNs over MPLS. [L3VPN-OAM] provides a
over MPLS. [L3VPN-OAM] provides a framework for the operation and framework for the operation and management of L3VPNs.
management of Layer 3 Virtual Private Networks (L3VPNs).
4.5. MPLS-TP OAM 4.5. MPLS-TP OAM
4.5.1. Overview 4.5.1. Overview
The MPLS working group has defined the OAM toolset that fulfills the The MPLS working group has defined the OAM toolset that fulfills the
requirements for MPLS-TP OAM. The full set of requirements for MPLS- requirements for MPLS-TP OAM. The full set of requirements for
TP OAM are defined in [MPLS-TP-OAM], and include both general MPLS-TP OAM are defined in [MPLS-TP-OAM] and include both general
requirements for the behavior of the OAM tools and a set of requirements for the behavior of the OAM tools and a set of
operations that should be supported by the OAM toolset. The set of operations that should be supported by the OAM toolset. The set of
mechanisms required are further elaborated in [TP-OAM-FW], which mechanisms required are further elaborated in [TP-OAM-FW], which
describes the general architecture of the OAM system as well as describes the general architecture of the OAM system and also gives
giving overviews of the functionality of the OAM toolset. overviews of the functionality of the OAM toolset.
Some of the basic requirements for the OAM toolset for MPLS-TP are: Some of the basic requirements for the OAM toolset for MPLS-TP are:
o MPLS-TP OAM must be able to support both an IP based and non-IP o MPLS-TP OAM must be able to support both an IP-based environment
based environment. If the network is IP based, i.e., IP routing and a non-IP-based environment. If the network is IP based, i.e.,
and forwarding are available, then the MPLS-TP OAM toolset should IP routing and forwarding are available, then the MPLS-TP OAM
rely on the IP routing and forwarding capabilities. On the other toolset should rely on the IP routing and forwarding capabilities.
hand, in environments where IP functionality is not available, the On the other hand, in environments where IP functionality is not
OAM tools must still be able to operate without dependence on IP available, the OAM tools must still be able to operate without
forwarding and routing. dependence on IP forwarding and routing.
o OAM packets and the user traffic are required to be congruent o OAM packets and the user traffic are required to be congruent
(i.e., OAM packets are transmitted in-band) and there is a need to (i.e., OAM packets are transmitted in-band), and there is a need
differentiate OAM packets from ordinary user packets in the data to differentiate OAM packets from ordinary user packets in the
plane. Inherent in this requirement is the principle that MPLS-TP data plane. Inherent in this requirement is the principle that
OAM be independent of any existing control-plane, although it MPLS-TP OAM be independent of any existing control plane, although
should not preclude use of the control-plane functionality. it should not preclude use of the control-plane functionality.
OAM packets are identified by the Generic Associated Label (GAL), OAM packets are identified by the Generic Associated Channel Label
which is a reserved MPLS label value (13). (GAL), which is a reserved MPLS label value (13).
4.5.2. Terminology 4.5.2. Terminology
Maintenance Entity (ME) Maintenance Entity (ME)
The MPLS-TP OAM tools are designed to monitor and manage a The MPLS-TP OAM tools are designed to monitor and manage a
Maintenance Entity (ME). An ME, as defined in [TP-OAM-FW], defines a Maintenance Entity (ME). An ME, as defined in [TP-OAM-FW],
relationship between two points of a transport path to which defines a relationship between two points of a transport path to
maintenance and monitoring operations apply. which maintenance and monitoring operations apply.
The term Maintenance Entity (ME) is used in ITU-T Recommendations The term "Maintenance Entity (ME)" is used in ITU-T
(e.g., [ITU-T-Y1731]), as well as in the MPLS-TP terminology Recommendations (e.g., [ITU-T-Y1731]), as well as in the MPLS-TP
([TP-OAM-FW]). terminology ([TP-OAM-FW]).
Maintenance Entity Group (MEG) Maintenance Entity Group (MEG)
The collection of one or more MEs that belongs to the same transport The collection of one or more MEs that belong to the same
path and that are maintained and monitored as a group are known as a transport path and that are maintained and monitored as a group
Maintenance Entity Group (based on [TP-OAM-FW]). are known as a Maintenance Entity Group (based on [TP-OAM-FW]).
Maintenance Point (MP) Maintenance Point (MP)
A Maintenance Point (MP) is a functional entity that is defined at a A Maintenance Point (MP) is a functional entity that is defined at
node in the network, and can initiate and/or react to OAM messages. a node in the network and can initiate and/or react to OAM
This document focuses on the data-plane functionality of MPs, while messages. This document focuses on the data-plane functionality
MPs interact with the control plane and with the management plane as of MPs, while MPs interact with the control plane and with the
well. management plane as well.
The term MP is used in IEEE 802.1ag, and was similarly adopted in The term "MP" is used in IEEE 802.1ag and was similarly adopted in
MPLS-TP ([TP-OAM-FW]). MPLS-TP ([TP-OAM-FW]).
Maintenance End Point (MEP) MEG End Point (MEP)
A Maintenance End Point (MEP) is one of the end points of an ME, and A MEG End Point (MEP) is one of the endpoints of an ME, and can
can initiate OAM messages and respond to them (based on [TP-OAM-FW]). initiate OAM messages and respond to them (based on [TP-OAM-FW]).
Maintenance Intermediate Point (MIP) MEG Intermediate Point (MIP)
In between MEPs, there are zero or more intermediate points, called In between MEPs, there are zero or more intermediate points,
Maintenance Entity Group Intermediate Points (based on [TP-OAM-FW]). called MEG Intermediate Points (based on [TP-OAM-FW]).
A Maintenance Intermediate Point (MIP) is an intermediate point that A MEG Intermediate Point (MIP) is an intermediate point that does
does not generally initiate OAM frames (one exception to this is the not generally initiate OAM frames (one exception to this is the
use of AIS notifications), but is able to respond to OAM frames that use of AIS notifications) but is able to respond to OAM frames
are destined to it. A MIP in MPLS-TP identifies OAM packets destined that are destined to it. A MIP in MPLS-TP identifies OAM packets
to it by the expiration of the TTL field in the OAM packet. The term destined to it by the expiration of the TTL field in the OAM
Maintenance Point is a general term for MEPs and MIPs. packet. The term "Maintenance Point" is a general term for MEPs
and MIPs.
Up and Down MEPs Up and Down MEPs
The IEEE 802.1ag [IEEE802.1Q] defines a distinction between Up MEPs IEEE 802.1ag [IEEE802.1Q] defines a distinction between Up MEPs
and Down MEPs. A MEP monitors traffic either in the direction facing and Down MEPs. A MEP monitors traffic in either the direction
the network, or in the direction facing the bridge. A Down MEP is a facing the network or the direction facing the bridge. A Down MEP
MEP that receives OAM packets from, and transmits them to the is a MEP that receives OAM packets from and transmits them to the
direction of the network. An Up MEP receives OAM packets from, and direction of the network. An Up MEP receives OAM packets from and
transmits them to the direction of the bridging entity. MPLS-TP ([TP- transmits them to the direction of the bridging entity. MPLS-TP
OAM-FW]) uses a similar distinction on the placement of the MEP - ([TP-OAM-FW]) uses a similar distinction on the placement of the
either at the ingress, egress, or forwarding function of the node MEP -- at either the ingress, egress, or forwarding function of
(Down / Up MEPs). This placement is important for localization of a the node (Down / Up MEPs). This placement is important for
failure. localization of a failure.
Note that the terms Up and Down MEPs are entirely unrelated to the Note that the terms "Up MEP" and "Down MEP" are entirely unrelated
conventional up/down terminology, where down means faulty, and up is to the conventional "Up"/"Down" terminology, where "Down" means
nonfaulty. faulty and "Up" means not faulty.
The distinction between Up and Down MEPs was defined in [TP-OAM-FW], The distinction between Up and Down MEPs was defined in
but has not been used in other MPLS-TP RFCs, as of the writing of [TP-OAM-FW], but has not been used in other MPLS-TP RFCs, as of
this document. the writing of this document.
4.5.3. Generic Associated Channel 4.5.3. Generic Associated Channel
In order to address the requirement for in-band transmission of MPLS- In order to address the requirement for in-band transmission of
TP OAM traffic, MPLS-TP uses a Generic Associated Channel (G-ACh), MPLS-TP OAM traffic, MPLS-TP uses a Generic Associated Channel
defined in [G-ACh] for LSP-based OAM traffic. This mechanism is based (G-ACh), defined in [G-ACh] for LSP-based OAM traffic. This
on the same concepts as the PWE3 ACH [PW-ACH] and VCCV [VCCV] mechanism is based on the same concepts as the PWE3 ACH [PW-ACH] and
mechanisms. However, to address the needs of LSPs as differentiated VCCV [VCCV] mechanisms. However, to address the needs of LSPs as
from PW, the following concepts were defined for [G-ACh]: differentiated from PW, the following concepts were defined for
[G-ACh]:
o An Associated Channel Header (ACH), that uses a format similar to o An Associated Channel Header (ACH), which uses a format similar to
the PW Control Word [PW-ACH], is a 4-byte header that is prepended the PW Control Word [PW-ACH], is a 4-byte header that is prepended
to OAM packets. to OAM packets.
o A Generic Associated Label (GAL). The GAL is a reserved MPLS label o A Generic Associated Channel Label (GAL). The GAL is a reserved
value (13) that indicates that the packet is an ACH packet and the MPLS label value (13) that indicates that the packet is an ACH
payload follows immediately after the label stack. packet and the payload follows immediately after the label stack.
It should be noted that while the G-ACh was defined as part of the It should be noted that while the G-ACh was defined as part of the
MPLS-TP definition effort, the G-ACh is a generic tool that can be MPLS-TP definition effort, the G-ACh is a generic tool that can be
used in MPLS in general, and not only in MPLS-TP. used in MPLS in general, and not only in MPLS-TP.
4.5.4. MPLS-TP OAM Toolset 4.5.4. MPLS-TP OAM Toolset
To address the functionality that is required of the OAM toolset, the To address the functionality that is required of the OAM toolset, the
MPLS WG conducted an analysis of the existing IETF and ITU-T OAM MPLS WG conducted an analysis of the existing IETF and ITU-T OAM
tools and their ability to fulfill the required functionality. The tools and their ability to fulfill the required functionality. The
conclusions of this analysis are documented in [OAM-Analys]. MPLS-TP conclusions of this analysis are documented in [OAM-Analys]. MPLS-TP
uses a mixture of OAM tools that are based on previous standards, and uses a mixture of OAM tools that are based on previous standards and
adapted to the requirements of [MPLS-TP-OAM]. Some of the main adapted to the requirements of [MPLS-TP-OAM]. Some of the main
building blocks of this solution are based on: building blocks of this solution are based on:
o Bidirectional Forwarding Detection ([BFD], [BFD-LSP]) for o Bidirectional Forwarding Detection ([BFD], [BFD-LSP]) for
proactive continuity check and connectivity verification. proactive Continuity Check and Connectivity Verification.
o LSP Ping as defined in [LSP-Ping] for on-demand connectivity o LSP Ping as defined in [LSP-Ping] for on-demand Connectivity
verification. Verification.
o New protocol packets, using G-ACH, to address different o New protocol packets, using G-ACH, to address different
functionality. functionality.
o Performance measurement protocols that are based on the o Performance measurement protocols.
functionality that is described in [ITU-T-Y1731].
The following sub-sections describe the OAM tools defined for MPLS-TP The following subsections describe the OAM tools defined for MPLS-TP
as described in [TP-OAM-FW]. as described in [TP-OAM-FW].
4.5.4.1. Continuity Check and Connectivity Verification 4.5.4.1. Continuity Check and Connectivity Verification
Continuity Check and Connectivity Verification are presented in Continuity Checks and Connectivity Verification are presented in
Section 2.2.7. of this document. As presented there, these tools may Section 2.2.7 of this document. As presented there, these tools may
be used either proactively or on-demand. When using these tools be used either proactively or on demand. When using these tools
proactively, they are generally used in tandem. proactively, they are generally used in tandem.
For MPLS-TP there are two distinct tools, the proactive tool is For MPLS-TP there are two distinct tools: the proactive tool is
defined in [TP-CC-CV] while the on-demand tool is defined in defined in [TP-CC-CV], while the on-demand tool is defined in
[OnDemand-CV]. In on-demand mode, this function should support [OnDemand-CV]. In on-demand mode, this function should support
monitoring between the MEPs and, in addition, between a MEP and MIP. monitoring between the MEPs and, in addition, between a MEP and MIP.
[TP-OAM-FW] highlights, when performing Connectivity Verification, [TP-OAM-FW] highlights, when performing Connectivity Verification,
the need for the CC-V messages to include unique identification of the need for the CC-V messages to include unique identification of
the MEG that is being monitored and the MEP that originated the the MEG that is being monitored and the MEP that originated the
message. message.
The proactive tool [TP-CC-CV] is based on extensions to BFD (see The proactive tool [TP-CC-CV] is based on extensions to BFD (see
Section 4.3.) with the additional limitation that the transmission Section 4.3) with the additional limitation that the transmission and
and receiving rates are based on configuration by the operator. The receiving rates are based on configuration by the operator. The
on-demand tool [OnDemand-CV] is an adaptation of LSP Ping (see on-demand tool [OnDemand-CV] is an adaptation of LSP Ping (see
Section 4.4.) for the required behavior of MPLS-TP. Section 4.4.1) for the required behavior of MPLS-TP.
4.5.4.2. Route Tracing 4.5.4.2. Route Tracing
[MPLS-TP-OAM] defines that there is a need for functionality that [MPLS-TP-OAM] defines that there is a need for functionality that
would allow a path end-point to identify the intermediate and end- would allow a path endpoint to identify the intermediate and
points of the path. This function would be used in on-demand mode. endpoints of the path. This function would be used in on-demand
Normally, this path will be used for bidirectional PW, LSP, and mode. Normally, this path will be used for bidirectional PW, LSP,
sections, however, unidirectional paths may be supported only if a and Sections; however, unidirectional paths may be supported only if
return path exists. The tool for this is based on the LSP Ping (see a return path exists. The tool for this is based on the LSP Ping
Section 4.4.) functionality and is described in [OnDemand-CV]. (see Section 4.4.1) functionality and is described in [OnDemand-CV].
4.5.4.3. Lock Instruct 4.5.4.3. Lock Instruct
The Lock Instruct function [Lock-Loop] is used to notify a transport The Lock Instruct function [Lock-Loop] is used to notify a transport-
path end-point of an administrative need to disable the transport path endpoint of an administrative need to disable the transport
path. This functionality will generally be used in conjunction with path. This functionality will generally be used in conjunction with
some intrusive OAM function, e.g., Performance measurement, some intrusive OAM function, e.g., performance measurement or
Diagnostic testing, to minimize the side-effect on user data traffic. diagnostic testing, to minimize the side-effect on user data traffic.
4.5.4.4. Lock Reporting 4.5.4.4. Lock Reporting
Lock Reporting is a function used by an end-point of a path to report Lock Reporting is a function used by an endpoint of a path to report
to its far-end end-point that a lock condition has been affected on to its far-end endpoint that a lock condition has been affected on
the path. the path.
4.5.4.5. Alarm Reporting 4.5.4.5. Alarm Reporting
Alarm Reporting [TP-Fault] provides the means to suppress alarms Alarm reporting [TP-Fault] provides the means to suppress alarms
following detection of defect conditions at the server sub-layer. following detection of defect conditions at the server sub-layer.
Alarm reporting is used by an intermediate point of a path, that Alarm reporting is used by an intermediate point of a path, that
becomes aware of a fault on the path, to report to the end-points of becomes aware of a fault on the path, to report to the endpoints of
the path. [TP-OAM-FW] states that this may occur as a result of a the path. [TP-OAM-FW] states that this may occur as a result of a
defect condition discovered at a server sub-layer. This generates an defect condition discovered at a server sub-layer. This generates an
Alarm Indication Signal (AIS) that continues until the fault is Alarm Indication Signal (AIS) that continues until the fault is
cleared. The consequent action of this function is detailed in cleared. The consequent action of this function is detailed in
[TP-OAM-FW]. [TP-OAM-FW].
4.5.4.6. Remote Defect Indication 4.5.4.6. Remote Defect Indication
Remote Defect Indication (RDI) is used proactively by a path end- Remote Defect Indication (RDI) is used proactively by a path endpoint
point to report to its peer end-point that a defect is detected on a to report to its peer endpoint that a defect is detected on a
bidirectional connection between them. [MPLS-TP-OAM] points out that bidirectional connection between them. [MPLS-TP-OAM] points out that
this function may be applied to a unidirectional LSP only if a return this function may be applied to a unidirectional LSP only if a return
path exists. [TP-OAM-FW] points out that this function is associated path exists. [TP-OAM-FW] points out that this function is associated
with the proactive CC-V function. with the proactive CC-V function.
4.5.4.7. Client Failure Indication 4.5.4.7. Client Failure Indication
Client Failure Indication (CFI) is defined in [MPLS-TP-OAM] to allow Client Failure Indication (CFI) is defined in [MPLS-TP-OAM] to allow
the propagation information from one edge of the network to the the propagation information from one edge of the network to the
other. The information concerns a defect to a client, in the case other. The information concerns a defect to a client, in the case
that the client does not support alarm notification. that the client does not support alarm notification.
4.5.4.8. Performance Monitoring 4.5.4.8. Performance Monitoring
The definition of MPLS performance monitoring was motivated by the The definition of MPLS performance monitoring was motivated by the
MPLS-TP requirements [MPLS-TP-OAM], but was defined generically for MPLS-TP requirements [MPLS-TP-OAM] but was defined generically for
MPLS in [MPLS-LM-DM]. An additional document [TP-LM-DM] defines a MPLS in [MPLS-LM-DM]. An additional document [TP-LM-DM] defines a
performance monitoring profile for MPLS-TP. performance monitoring profile for MPLS-TP.
4.5.4.8.1. Packet Loss Measurement (LM) 4.5.4.8.1. Packet Loss Measurement (LM)
Packet Loss Measurement is a function used to verify the quality of Packet Loss Measurement is a function used to verify the quality of
the service. Packet loss, as defined in [IPPM-1LM] and [MPLS-TP-OAM], the service. Packet loss, as defined in [IPPM-1LM] and
indicates the ratio of the number of user packets lost to the total [MPLS-TP-OAM], indicates the ratio of the number of user packets lost
number of user packets sent during a defined time interval. to the total number of user packets sent during a defined time
interval.
There are two possible ways of determining this measurement: There are two possible ways of determining this measurement:
o Using OAM packets, it is possible to compute the statistics based o Using OAM packets, it is possible to compute the statistics based
on a series of OAM packets. This, however, has the disadvantage of on a series of OAM packets. This, however, has the disadvantage
being artificial, and may not be representative since part of the of being artificial and may not be representative since part of
packet loss may be dependent upon packet sizes and upon the the packet loss may be dependent upon packet sizes and upon the
implementation of the MEPs that take part in the protocol. implementation of the MEPs that take part in the protocol.
o Sending delimiting messages for the start and end of a measurement o Delimiting messages can be sent at the start and end of a
period during which the source and sink of the path count the measurement period during which the source and sink of the path
packets transmitted and received. After the end delimiter, the count the packets transmitted and received. After the end
ratio would be calculated by the path OAM entity. delimiter, the ratio would be calculated by the path OAM entity.
4.5.4.8.2. Packet Delay Measurement (DM) 4.5.4.8.2. Packet Delay Measurement (DM)
Packet Delay Measurement is a function that is used to measure one- Packet Delay Measurement is a function that is used to measure one-
way or two-way delay of a packet transmission between a pair of the way or two-way delay of a packet transmission between a pair of the
end-points of a path (PW, LSP, or Section). Where: endpoints of a path (PW, LSP, or Section). Where:
o One-way packet delay, as defined in [IPPM-1DM], is the time o One-way packet delay, as defined in [IPPM-1DM], is the time
elapsed from the start of transmission of the first bit of the elapsed from the start of transmission of the first bit of the
packet by a source node until the reception of the last bit of packet by a source node until the reception of the last bit of
that packet by the destination node. Note that one-way delay that packet by the destination node. Note that one-way delay
measurement requires the clocks of the two end-points to be measurement requires the clocks of the two endpoints to be
synchronized. synchronized.
o Two-way packet delay, as defined in [IPPM-2DM], is the time o Two-way packet delay, as defined in [IPPM-2DM], is the time
elapsed from the start of transmission of the first bit of the elapsed from the start of transmission of the first bit of the
packet by a source node until the reception of the last bit of the packet by a source node until the reception of the last bit of the
loop-backed packet by the same source node, when the loopback is looped-back packet by the same source node, when the loopback is
performed at the packet's destination node. Note that due to performed at the packet's destination node. Note that due to
possible path asymmetry, the one-way packet delay from one end- possible path asymmetry, the one-way packet delay from one
point to another is not necessarily equal to half of the two-way endpoint to another is not necessarily equal to half of the
packet delay. two-way packet delay. As opposed to one-way delay measurement,
As opposed to one-way delay measurement, two-way delay measurement two-way delay measurement does not require the two endpoints to be
does not require the two end-points to be synchronized. synchronized.
For each of these two metrics, the DM function allows the MEP to For each of these two metrics, the DM function allows the MEP to
measure the delay, as well as the delay variation. Delay measurement measure the delay, as well as the delay variation. Delay
is performed by exchanging timestamped OAM packets between the measurement is performed by exchanging timestamped OAM packets
participating MEPs. between the participating MEPs.
4.6. Pseudowire OAM 4.6. Pseudowire OAM
4.6.1. Pseudowire OAM using Virtual Circuit Connectivity Verification 4.6.1. Pseudowire OAM Using Virtual Circuit Connectivity Verification
(VCCV) (VCCV)
VCCV, as defined in [VCCV], provides a means for end-to-end fault VCCV, as defined in [VCCV], provides a means for end-to-end fault
detection and diagnostics tools to be used for PWs (regardless of the detection and diagnostic tools to be used for PWs (regardless of the
underlying tunneling technology). The VCCV switching function underlying tunneling technology). The VCCV switching function
provides a control channel associated with each PW. [VCCV] defines provides a Control Channel associated with each PW. [VCCV] defines
three Control Channel (CC) types, i.e., three possible methods for three Control Channel (CC) types, i.e., three possible methods for
transmitting and identifying OAM messages: transmitting and identifying OAM messages:
o CC Type 1: In-band VCCV, as described in [VCCV], is also referred o Control Channel Type 1: In-band VCCV, as described in [VCCV], is
to as "PWE3 Control Word with 0001b as first nibble". It uses the also referred to as "PWE3 Control Word with 0001b as first
PW Associated Channel Header [PW-ACH]. nibble". It uses the PW Associated Channel Header [PW-ACH].
o CC Type 2: Out-of-band VCCV [VCCV], is also referred to as "MPLS o Control Channel Type 2: Out-of-band VCCV, as described in [VCCV],
Router Alert Label". In this case the control channel is created is also referred to as "MPLS Router Alert Label". In this case,
by using the MPLS router alert label [MPLS-ENCAPS] immediately the Control Channel is created by using the MPLS router alert
above the PW label. label [MPLS-ENCAPS] immediately above the PW label.
o CC Type 3: TTL expiry VCCV [VCCV], is also referred to as "MPLS PW o Control Channel Type 3: TTL expiry VCCV, as described in [VCCV],
Label with TTL == 1", i.e., the control channel is identified when is also referred to as "MPLS PW Label with TTL == 1", i.e., the
the value of the TTL field in the PW label is set to 1. Control Channel is identified when the value of the TTL field in
the PW label is set to 1.
VCCV currently supports the following OAM tools: ICMP Ping, LSP Ping, VCCV currently supports the following OAM tools: ICMP Ping, LSP Ping,
and BFD. ICMP and LSP Ping are IP encapsulated before being sent over and BFD. ICMP and LSP Ping are IP encapsulated before being sent
the PW ACH. BFD for VCCV [BFD-VCCV] supports two modes of over the PW ACH. BFD for VCCV [BFD-VCCV] supports two modes of
encapsulation - either IP/UDP encapsulated (with IP/UDP header) or encapsulation -- either IP/UDP encapsulated (with IP/UDP header) or
PW-ACH encapsulated (with no IP/UDP header) and provides support to PW-ACH encapsulated (with no IP/UDP header) -- and provides support
signal the AC status. The use of the VCCV control channel provides to signal the AC status. The use of the VCCV Control Channel
the context, based on the MPLS-PW label, required to bind and provides the context, based on the MPLS-PW label, required to bind
bootstrap the BFD session to a particular pseudo wire (FEC), and bootstrap the BFD session to a particular pseudowire (FEC),
eliminating the need to exchange Discriminator values. eliminating the need to exchange Discriminator values.
VCCV consists of two components: (1) signaled component to VCCV consists of two components: (1) the signaled component to
communicate VCCV capabilities as part of VC label, and (2) switching communicate VCCV capabilities as part of the VC label, and (2) the
component to cause the PW payload to be treated as a control packet. switching component to cause the PW payload to be treated as a
control packet.
VCCV is not directly dependent upon the presence of a control plane. VCCV is not directly dependent upon the presence of a control plane.
The VCCV capability advertisement may be performed as part of the PW The VCCV capability advertisement may be performed as part of the PW
signaling when LDP is used. In case of manual configuration of the signaling when LDP is used. In case of manual configuration of the
PW, it is the responsibility of the operator to set consistent PW, it is the responsibility of the operator to set consistent
options at both ends. The manual option was created specifically to options at both ends. The manual option was created specifically to
handle MPLS-TP use cases where no control plane was a requirement. handle MPLS-TP use cases where no control plane was a requirement.
However, new use cases such as pure mobile backhaul find this However, new use cases such as pure mobile backhaul find this
functionality useful too. functionality useful too.
The PWE3 working group has conducted an implementation survey of VCCV The PWE3 working group has conducted an implementation survey of VCCV
[VCCV-SURVEY], which analyzes which VCCV mechanisms are used in [VCCV-SURVEY] that analyzes which VCCV mechanisms are used in
practice. practice.
4.6.2. Pseudowire OAM using G-ACh 4.6.2. Pseudowire OAM Using G-ACh
As mentioned above, VCCV enables OAM for PWs by using a control As mentioned above, VCCV enables OAM for PWs by using a Control
channel for OAM packets. When PWs are used in MPLS-TP networks, Channel for OAM packets. When PWs are used in MPLS-TP networks,
rather than the control channels defined in VCCV, the G-ACh can be rather than the Control Channels defined in VCCV, the G-ACh can be
used as an alternative control channel. The usage of the G-ACh for used as an alternative Control Channel. The usage of the G-ACh for
PWs is defined in [PW-G-ACh]. PWs is defined in [PW-G-ACh].
4.6.3. Attachment Circuit - Pseudowire Mapping 4.6.3. Attachment Circuit - Pseudowire Mapping
The PWE3 working group has defined a mapping and notification of The PWE3 working group has defined a mapping and notification of
defect states between a pseudowire (PW) and the Attachment Circuits defect states between a pseudowire (PW) and the Attachment Circuits
(ACs) of the end-to-end emulated service. This mapping is of key (ACs) of the end-to-end emulated service. This mapping is of key
importance to the end-to-end functionality. Specifically, the mapping importance to the end-to-end functionality. Specifically, the
is provided by [PW-MAP], by [L2TP-EC] for L2TPv3 pseudowires, and mapping is provided by [PW-MAP], by [L2TP-EC] for L2TPv3 pseudowires,
Section 5.3 of [ATM-L2] for ATM. and by Section 5.3 of [ATM-L2] for ATM.
[L2VPN-OAM] provides the requirements and framework for OAM in the [L2VPN-OAM] provides the requirements and framework for OAM in the
context of Layer 2 Virtual Private Networks (L2VPN), and specifically context of Layer 2 Virtual Private Networks (L2VPNs), and
it also defines the OAM layering of L2VPNs over pseudowires. specifically it also defines the OAM layering of L2VPNs over
pseudowires.
The mapping defined in [Eth-Int] allows an end-to-end emulated The mapping defined in [Eth-Int] allows an end-to-end emulated
Ethernet service over pseudowires. Ethernet service over pseudowires.
4.7. OWAMP and TWAMP 4.7. OWAMP and TWAMP
4.7.1. Overview 4.7.1. Overview
The IPPM working group in the IETF defines common criteria and The IPPM working group in the IETF defines common criteria and
metrics for measuring performance of IP traffic ([IPPM-FW]). Some of metrics for measuring performance of IP traffic ([IPPM-FW]). Some of
the key RFCs published by this working group have defined metrics for the key RFCs published by this working group have defined metrics for
measuring connectivity [IPPM-Con], delay ([IPPM-1DM], [IPPM-2DM]), measuring connectivity [IPPM-Con], delay ([IPPM-1DM], [IPPM-2DM]),
and packet loss [IPPM-1LM]. It should be noted that the work of the and packet loss [IPPM-1LM]. It should be noted that the work of the
IETF in the context of performance metrics is not limited to IP IETF in the context of performance metrics is not limited to IP
networks; [PM-CONS] presents general guidelines for considering new networks; [PM-CONS] presents general guidelines for considering new
performance metrics. performance metrics.
The IPPM working group has defined not only metrics for performance The IPPM working group has defined not only metrics for performance
measurement, but also protocols that define how the measurement is measurement but also protocols that define how the measurement is
carried out. The One-way Active Measurement Protocol [OWAMP] and the carried out. The One-Way Active Measurement Protocol [OWAMP] and the
Two-Way Active Measurement Protocol [TWAMP] define a method and Two-Way Active Measurement Protocol [TWAMP] each define a method and
protocol for measuring performance metrics in IP networks. protocol for measuring performance metrics in IP networks.
OWAMP [OWAMP] enables measurement of one-way characteristics of IP OWAMP [OWAMP] enables measurement of one-way characteristics of IP
networks, such as one-way packet loss and one-way delay. For its networks, such as one-way packet loss and one-way delay. For its
proper operation OWAMP requires accurate time of day setting at its proper operation, OWAMP requires accurate time-of-day setting at its
end points. endpoints.
TWAMP [TWAMP] is a similar protocol that enables measurement of both TWAMP [TWAMP] is a similar protocol that enables measurement of both
one-way and two-way (round trip) characteristics. one-way and two-way (round-trip) characteristics.
OWAMP and TWAMP are both comprised of two separate protocols: OWAMP and TWAMP are each comprised of two separate protocols:
o OWAMP-Control/TWAMP-Control: used to initiate, start, and stop o OWAMP-Control/TWAMP-Control: used to initiate, start, and stop
test sessions and to fetch their results. Continuity Check and test sessions and to fetch their results. Continuity Check and
Connectivity Verification are tested and confirmed by establishing Connectivity Verification are tested and confirmed by establishing
the OWAMP/TWAMP Control Protocol TCP connection. the OWAMP/TWAMP Control Protocol TCP connection.
o OWAMP-Test/TWAMP-Test: used to exchange test packets between two o OWAMP-Test/TWAMP-Test: used to exchange test packets between two
measurement nodes. Enables the loss and delay measurement measurement nodes. Enables the loss and delay measurement
functions, as well as detection of other anomalies, such as packet functions, as well as detection of other anomalies, such as packet
duplication and packet reordering. duplication and packet reordering.
It should be noted that while [OWAMP] and [TWAMP] define tools for It should be noted that while [OWAMP] and [TWAMP] define tools for
performance measurement, they do not define the accuracy of these performance measurement, they do not define the accuracy of these
tools. The accuracy depends on scale, implementation and network tools. The accuracy depends on scale, implementation, and network
configurations. configurations.
Alternative protocols for performance monitoring are defined, for Alternative protocols for performance monitoring are defined, for
example, in MPLS-TP OAM ([MPLS-LM-DM], [TP-LM-DM]), and in Ethernet example, in MPLS-TP OAM ([MPLS-LM-DM], [TP-LM-DM]) and in Ethernet
OAM [ITU-T-Y1731]. OAM [ITU-T-Y1731].
4.7.2. Control and Test Protocols 4.7.2. Control and Test Protocols
OWAMP and TWAMP control protocols run over TCP, while the test OWAMP and TWAMP control protocols run over TCP, while the test
protocols run over UDP. The purpose of the control protocols is to protocols run over UDP. The purpose of the control protocols is to
initiate, start, and stop test sessions, and for OWAMP to fetch initiate, start, and stop test sessions, and for OWAMP to fetch
results. The test protocols introduce test packets (which contain results. The test protocols introduce test packets (which contain
sequence numbers and timestamps) along the IP path under test sequence numbers and timestamps) along the IP path under test
according to a schedule, and record statistics of packet arrival. according to a schedule, and they record statistics of packet
Multiple sessions may be simultaneously defined, each with a session arrival. Multiple sessions may be simultaneously defined, each with
identifier, and defining the number of packets to be sent, the amount a session identifier, and defining the number of packets to be sent,
of padding to be added (and thus the packet size), the start time, the amount of padding to be added (and thus the packet size), the
and the send schedule (which can be either a constant time between start time, and the send schedule (which can be either a constant
test packets or exponentially distributed pseudo-random). Statistics time between test packets or exponentially distributed
recorded conform to the relevant IPPM RFCs. pseudorandomly). Statistics recorded conform to the relevant IPPM
RFCs.
From a security perspective, OWAMP and TWAMP test packets are hard to From a security perspective, OWAMP and TWAMP test packets are hard to
detect because they are simply UDP streams between negotiated port detect because they are simply UDP streams between negotiated port
numbers, with potentially nothing static in the packets. OWAMP and numbers, with potentially nothing static in the packets. OWAMP and
TWAMP also include optional authentication and encryption for both TWAMP also include optional authentication and encryption for both
control and test packets. control and test packets.
4.7.3. OWAMP 4.7.3. OWAMP
OWAMP defines the following logical roles: Session-Sender, Session- OWAMP defines the following logical roles: Session-Sender,
Receiver, Server, Control-Client, and Fetch-Client. The Session- Session-Receiver, Server, Control-Client, and Fetch-Client. The
Sender originates test traffic that is received by the Session- Session-Sender originates test traffic that is received by the
Receiver. The Server configures and manages the session, as well as Session-Receiver. The Server configures and manages the session, as
returning the results. The Control-Client initiates requests for well as returning the results. The Control-Client initiates requests
test sessions, triggers their start, and may trigger their for test sessions, triggers their start, and may trigger their
termination. The Fetch-Client requests the results of a completed termination. The Fetch-Client requests the results of a completed
session. Multiple roles may be combined in a single host - for session. Multiple roles may be combined in a single host -- for
example, one host may play the roles of Control-Client, Fetch-Client, example, one host may play the roles of Control-Client, Fetch-Client,
and Session-Sender, and a second playing the roles of Server and and Session-Sender, and a second may play the roles of Server and
Session-Receiver. Session-Receiver.
In a typical OWAMP session the Control-Client establishes a TCP In a typical OWAMP session, the Control-Client establishes a TCP
connection to port 861 of the Server, which responds with a server connection to port 861 of the Server, which responds with a Server
greeting message indicating supported security/integrity modes. The greeting message indicating supported security/integrity modes. The
Control-Client responds with the chosen communications mode and the Control-Client responds with the chosen communications mode, and the
Server accepts the mode. The Control-Client then requests and fully Server accepts the mode. The Control-Client then requests and fully
describes a test session to which the Server responds with its describes a test session to which the Server responds with its
acceptance and supporting information. More than one test session acceptance and supporting information. More than one test session
may be requested with additional messages. The Control-Client then may be requested with additional messages. The Control-Client then
starts a test session and the Server acknowledges, and instructs the starts a test session; the Server acknowledges and then instructs the
Session-Sender to start the test. The Session-Sender then sends test Session-Sender to start the test. The Session-Sender then sends test
packets with pseudorandom padding to the Session-Receiver until the packets with pseudorandom padding to the Session-Receiver until the
session is complete or until the Control-client stops the session. session is complete or until the Control-Client stops the session.
Once finished, the Session-Sender reports to the Server which
recovers data from the Session-Receiver. The Fetch-Client can then Once finished, the Session-Sender reports to the Server, which
recovers data from the Session-Receiver. The Fetch-Client can then
send a fetch request to the Server, which responds with an send a fetch request to the Server, which responds with an
acknowledgement and immediately thereafter the result data. acknowledgement and, immediately thereafter, the result data.
4.7.4. TWAMP 4.7.4. TWAMP
TWAMP defines the following logical roles: session-sender, session- TWAMP defines the following logical roles: Session-Sender,
reflector, server, and control-client. These are similar to the Session-Reflector, Server, and Control-Client. These are similar to
OWAMP roles, except that the Session-Reflector does not collect any the OWAMP roles, except that the Session-Reflector does not collect
packet information, and there is no need for a Fetch-Client. any packet information, and there is no need for a Fetch-Client.
In a typical TWAMP session the Control-Client establishes a TCP In a typical TWAMP session, the Control-Client establishes a TCP
connection to port 862 of the Server, and mode is negotiated as in connection to port 862 of the Server, and the mode is negotiated as
OWAMP. The Control-Client then requests sessions and starts them. in OWAMP. The Control-Client then requests sessions and starts them.
The Session-Sender sends test packets with pseudorandom padding to The Session-Sender sends test packets with pseudorandom padding to
the Session-Reflector which returns them with insertion of the Session-Reflector, which returns them with timestamps inserted.
timestamps.
4.8. TRILL 4.8. TRILL
The requirements of OAM in TRILL are defined in [TRILL-OAM]. The The requirements of OAM in TRILL are defined in [TRILL-OAM]. The
challenge in TRILL OAM, much like in MPLS networks, is that traffic challenge in TRILL OAM, much like in MPLS networks, is that traffic
between RBridges RB1 and RB2 may be forwarded through more than one between RBridges RB1 and RB2 may be forwarded through more than one
path. Thus, an OAM protocol between RBridges RB1 and RB2 must be able path. Thus, an OAM protocol between RBridges RB1 and RB2 must be
to monitor all the available paths between the two RBridge. able to monitor all the available paths between the two RBridges.
During the writing of this document the detailed definition of the During the writing of this document, the detailed definition of the
TRILL OAM tools are still work in progress. This subsection presents TRILL OAM tools is still work in progress. This subsection presents
the main requirements of TRILL OAM. the main requirements of TRILL OAM.
The main requirements defined in [TRILL-OAM] are: The main requirements defined in [TRILL-OAM] are:
o Continuity Checking (CC) - the TRILL OAM protocol must support a o Continuity Checking (CC) - the TRILL OAM protocol must support a
function for CC between any two RBridges RB1 and RB2. function for CC between any two RBridges RB1 and RB2.
o Connectivity Verification (CV) - connectivity between two RBridges o Connectivity Verification (CV) - connectivity between two RBridges
RB1 and RB2 can be verified on a per-flow basis. RB1 and RB2 can be verified on a per-flow basis.
o Path Tracing - allows an RBridge to trace all the available paths o Path Tracing - allows an RBridge to trace all the available paths
to a peer RBridge. to a peer RBridge.
o Performance monitoring - allows an RBridge to monitor the packet o Performance monitoring - allows an RBridge to monitor the packet
loss and packet delay to a peer RBridge. loss and packet delay to a peer RBridge.
5. Summary 5. Summary
This section summarizes the OAM tools and functions presented in this This section summarizes the OAM tools and functions presented in this
document. This summary is an index to some of the main OAM tools document. This summary is an index to some of the main OAM tools
defined in the IETF. This compact index that can be useful to all defined in the IETF. This compact index can be useful to all readers
readers from network operators to standards development from network operators to standards development organizations. The
organizations. The summary includes a short subsection that presents summary includes a short subsection that presents some guidance to
some guidance to network equipment vendors. network equipment vendors.
5.1. Summary of OAM Tools 5.1. Summary of OAM Tools
This subsection provides a short summary of each of the OAM toolsets This subsection provides a short summary of each of the OAM toolsets
described in this document. described in this document.
A detailed list of the RFCs related to each toolset is given in A detailed list of the RFCs related to each toolset is given in
Appendix A.1. Appendix A.1.
+-----------+------------------------------------------+------------+ +-----------+------------------------------------------+------------+
| Toolset | Description | Transport | | Toolset | Description | Transport |
| | | Technology | | | | Technology |
+-----------+------------------------------------------+------------+ +-----------+------------------------------------------+------------+
|IP Ping | Ping ([IntHost], [NetTerms]) is a simple | IPv4/IPv6 | |IP Ping | Ping ([IntHost], [NetTerms]) is a simple | IPv4/IPv6 |
| | application for testing reachability that| | | | application for testing reachability that| |
| | uses ICMP Echo messages ([ICMPv4], | | | | uses ICMP Echo messages ([ICMPv4], | |
| | [ICMPv6]). | | | | [ICMPv6]). | |
+-----------+------------------------------------------+------------+ +-----------+------------------------------------------+------------+
|IP | Traceroute ([TCPIP-Tools], [NetTools]) is| IPv4/IPv6 | |IP | Traceroute ([TCPIP-Tools], [NetTools]) is| IPv4/IPv6 |
|Traceroute | an application that allows users to trace| | |Traceroute | an application that allows users to trace| |
| | the path between an IP source and an IP | | | | the path between an IP source and an IP | |
| | destination, i.e., to identify the nodes | | | | destination, i.e., to identify the nodes | |
| | along the path. If more than one path | | | | along the path. If more than one path | |
| | exists between the source and destination| | | | exists between the source and | |
| | Traceroute traces *a* path. The most | | | | destination, Traceroute traces *a* path. | |
| | common implementation of Traceroute | | | | The most common implementation of | |
| | uses UDP probe messages, although there | | | | Traceroute uses UDP probe messages, | |
| | are other implementations that use | | | | although there are other implementations | |
| | different probes, such as ICMP or TCP. | | | | that use different probes, such as ICMP | |
| | Paris Traceroute [PARIS] is an extension | | | | or TCP. Paris Traceroute [PARIS] is an | |
| | that attempts to discovers all the | | | | extension that attempts to discover all | |
| | available paths from A to B by scanning | | | | the available paths from A to B by | |
| | different values of header fields. | | | | scanning different values of header | |
+-----------+------------------------------------------+------------+ | | fields. | |
|BFD | Bidirectional Forwarding Detection (BFD) | generic | +-----------+------------------------------------------+------------+
| | is defined in [BFD] as a framework for a | | |BFD | Bidirectional Forwarding Detection (BFD) | generic |
| | lightweight generic OAM tool. The | | | | is defined in [BFD] as a framework for a | |
| | intention is to define a base tool | | | | lightweight generic OAM tool. The | |
| | that can be used with various | | | | intention is to define a base tool | |
| | encapsulation types, network | | | | that can be used with various | |
| | environments, and in various medium | | | | encapsulation types, network | |
| | types. | | | | environments, and various medium | |
+-----------+------------------------------------------+------------+ | | types. | |
|MPLS OAM | MPLS LSP Ping, as defined in [MPLS-OAM], | MPLS | +-----------+------------------------------------------+------------+
| | [MPLS-OAM-FW] and [LSP-Ping], is an OAM | | |MPLS OAM | MPLS LSP Ping, as defined in [MPLS-OAM], | MPLS |
| | tool for point-to-point and | | | | [MPLS-OAM-FW], and [LSP-Ping], is an OAM | |
| | point-to-multipoint MLPS LSPs. | | | | tool for point-to-point and | |
| | It includes two main functions: Ping and | | | | point-to-multipoint MPLS LSPs. | |
| | Traceroute. | | | | It includes two main functions: Ping and | |
| | BFD [BFD-LSP] is an alternative means for| | | | Traceroute. | |
| | detecting MPLS LSP data plane failures. | | | | BFD [BFD-LSP] is an alternative means for| |
+-----------+------------------------------------------+------------+ | | detecting MPLS LSP data-plane failures. | |
|MPLS-TP OAM| MPLS-TP OAM is defined in a set of RFCs. | MPLS-TP | +-----------+------------------------------------------+------------+
| | The OAM requirements for MPLS Transport | | |MPLS-TP OAM| MPLS-TP OAM is defined in a set of RFCs. | MPLS-TP |
| | Profile (MPLS-TP) are defined in | | | | The OAM requirements for MPLS Transport | |
| | [MPLS-TP-OAM]. Each of the tools in the | | | | Profile (MPLS-TP) are defined in | |
| | OAM toolset is defined in its own RFC, as| | | | [MPLS-TP-OAM]. Each of the tools in the | |
| | specified in Section A.1. | | | | OAM toolset is defined in its own RFC, as| |
+-----------+------------------------------------------+------------+ | | specified in Appendix A.1. | |
|Pseudowire | The PWE3 OAM architecture defines control| Pseudowire | +-----------+------------------------------------------+------------+
|OAM | channels that support the use of existing| | |Pseudowire | The PWE3 OAM architecture defines Control| Pseudowire |
| | IETF OAM tools to be used for a pseudo- | | |OAM | Channels that support the use of existing| |
| | wire (PW). The control channels that are| | | | IETF OAM tools to be used for a pseudo- | |
| | defined in [VCCV] and [PW-G-ACh] may be | | | | wire (PW). The Control Channels that are| |
| | used in conjunction with ICMP Ping, LSP | | | | defined in [VCCV] and [PW-G-ACh] may be | |
| | Ping, and BFD to perform CC and CV | | | | used in conjunction with ICMP Ping, LSP | |
| | functionality. In addition the channels | | | | Ping, and BFD to perform CC and CV | |
| | support use of any of the MPLS-TP based | | | | functionality. In addition, the channels| |
| | OAM tools for completing their respective| | | | support use of any of the MPLS-TP-based | |
| | OAM functionality for a PW. | | | | OAM tools for completing their respective| |
+-----------+------------------------------------------+------------+ | | OAM functionality for a PW. | |
|OWAMP and | The One Way Active Measurement Protocol | IPv4/IPv6 | +-----------+------------------------------------------+------------+
|TWAMP | [OWAMP] and the Two Way Active Measure- | | |OWAMP and | The One-Way Active Measurement Protocol | IPv4/IPv6 |
| | ment Protocols [TWAMP] are two protocols | | |TWAMP | [OWAMP] and the Two-Way Active Measure- | |
| | defined in the IP Performance Metrics | | | | ment Protocol [TWAMP] are two protocols | |
| | (IPPM) working group in the IETF. These | | | | defined in the IP Performance Metrics | |
| | protocols allow various performance | | | | (IPPM) working group in the IETF. These | |
| | metrics to be measured, such as packet | | | | protocols allow various performance | |
| | loss, delay and delay variation, | | | | metrics to be measured, such as packet | |
| | duplication and reordering. | | | | loss, delay, delay variation, | |
+-----------+------------------------------------------+------------+ | | duplication, and reordering. | |
|TRILL OAM | The requirements of OAM in TRILL are | TRILL | +-----------+------------------------------------------+------------+
| | defined in [TRILL-OAM]. These | | |TRILL OAM | The requirements of OAM in TRILL are | TRILL |
| | requirements include continuity checking,| | | | defined in [TRILL-OAM]. These | |
| | connectivity verification, path tracing | | | | requirements include Continuity Checking,| |
| | and performance monitoring. During the | | | | Connectivity Verification, path tracing, | |
| | writing of this document the detailed | | | | and performance monitoring. During the | |
| | definition of the TRILL OAM tools | | | | writing of this document, the detailed | |
| | is work in progress. | | | | definition of the TRILL OAM tools | |
+-----------+------------------------------------------+------------+ | | is work in progress. | |
Table 3 Summary of OAM-related IETF Tools +-----------+------------------------------------------+------------+
5.2. Summary of OAM Functions -----------+------------------------------------------+------------+
Table 3: Summary of OAM-Related IETF Tools
5.2. Summary of OAM Functions
Table 4 summarizes the OAM functions that are supported in each of Table 4 summarizes the OAM functions that are supported in each of
the toolsets that were analyzed in this section. The columns of this the toolsets that were analyzed in this section. The columns of this
tables are the typical OAM functions described in Section 1.3. table are the typical OAM functions described in Section 1.3.
+-----------+-------+--------+--------+-------+----------+ +-----------+----------+-------------+----------+----------+-----------+
| |Continu|Connecti|Path |Perform|Other | | |Continuity|Connectivity |Path |Perf. |Other |
| |ity |vity |Discover|ance |Function | | Toolset |Check |Verification |Discovery |Monitoring|Functions |
| |Check |Verifica|y |Monitor|s | | | | | | | |
| Toolset | |tion | |ing | | +-----------+----------+-------------+----------+----------+-----------+
+-----------+-------+--------+--------+-------+----------+ |IP Ping |Echo | | | | |
|IP Ping |Echo | | | | | +-----------+----------+-------------+----------+----------+-----------+
+ --------- + ----- + ------ + ------ + ----- + -------- + |IP | | |Traceroute| | |
|IP | | |Tracerou| | | |Traceroute | | | | | |
|Traceroute | | |te | | | +-----------+----------+-------------+----------+----------+-----------+
+ --------- + ----- + ------ + ------ + ----- + -------- + |BFD |BFD |BFD Control | | |RDI using |
|BFD |BFD |BFD | | |RDI usi- | | |Control/ | | | |BFD Control|
| |Control|Control | | |ng BFD | | |Echo | | | | |
| |/ Echo | | | |Control | +-----------+----------+-------------+----------+----------+-----------+
+ --------- + ----- + ------ + ------ + ----- + -------- + |MPLS OAM | |"Ping" mode |"Trace- | | |
|MPLS OAM | |"Ping" |"Tracero| | | |(LSP Ping) | | |route" | | |
|(LSP Ping) | |mode |ute" | | | | | | |mode | | |
| | | |mode | | | +-----------+----------+-------------+----------+----------+-----------+
+ --------- + ----- + ------ + ------ + ----- + -------- + |MPLS-TP |CC |CV/proactive |Route |-LM |-Diagnostic|
|MPLS-TP |CC |CV/pro- |Route |-LM |-Diagnos- | |OAM | |or on demand |Tracing |-DM | Test |
|OAM | |active |Tracing |-DM | tic Test | | | | | | |-Lock |
| | |or on- | | |-Lock | | | | | | |-Alarm |
| | |demand | | |-Alarm | | | | | | | Reporting |
| | | | | |Reporting | | | | | | |-Client |
| | | | | |-Client | | | | | | | Failure |
| | | | | |Failure | | | | | | | Indication|
| | | | | |Indication| | | | | | |-RDI |
| | | | | |-RDI | +-----------+----------+-------------+----------+----------+-----------+
+ --------- + ----- + ------ + ------ + ----- + -------- + |Pseudowire |BFD |-BFD |LSP Ping | | |
|Pseudowire |BFD |-BFD |LSP-Ping| | | |OAM | |-ICMP Ping | | | |
|OAM | |-ICMP | | | | | | |-LSP Ping | | | |
| | | Ping | | | | +-----------+----------+-------------+----------+----------+-----------+
| | |-LSP- | | | | |OWAMP and | - control | |-DM | |
| | | Ping | | | | |TWAMP | protocol | |-LM | |
+ --------- + ----- + ------ + ------ + ----- + -------- + +-----------+----------+-------------+----------+----------+-----------+
|OWAMP and | - control | |-Delay | | |TRILL OAM |CC |CV |Path |-DM | |
|TWAMP | protocol | | measur| | | | | |tracing |-LM | |
| | | | ement | | +-----------+----------+-------------+----------+----------+-----------+
| | | |-Packet| |
| | | | loss | |
| | | | measur| |
| | | | ement | |
+ --------- + ----- + ------ + ------ + ----- + -------- +
|TRILL OAM |CC |CV |Path |-Delay | |
| | | |tracing | measur| |
| | | | | ement | |
| | | | |-Packet| |
| | | | | loss | |
| | | | | measur| |
| | | | | ement | |
+-----------+-------+--------+--------+-------+----------+
Table 4 Summary of the OAM Functionality in IETF OAM Tools
5.3. Guidance to Network Equipment Vendors Table 4: Summary of the OAM Functionality in IETF OAM Tools
As mentioned in Section 1.4. , it is imperative for OAM tools to be 5.3. Guidance to Network Equipment Vendors
capable of testing the actual data plane in as much accuracy as
possible. While this guideline may appear obvious, it is worthwhile As mentioned in Section 1.4, it is imperative for OAM tools to be
capable of testing the actual data plane with as much accuracy as
possible. While this guideline may appear obvious, it is worthwhile
to emphasize the key importance of enforcing fate-sharing between OAM to emphasize the key importance of enforcing fate-sharing between OAM
traffic that monitors the data plane and the data plane traffic it traffic that monitors the data plane and the data-plane traffic it
monitors. monitors.
6. Security Considerations 6. Security Considerations
OAM is tightly coupled with the stability of the network. A OAM is tightly coupled with the stability of the network. A
successful attack on an OAM protocol can create a false illusion of successful attack on an OAM protocol can create a false illusion of
non-existent failures, or prevent the detection of actual ones. In nonexistent failures or prevent the detection of actual ones. In
both cases the attack may result in denial of service. both cases, the attack may result in denial of service.
Some of the OAM tools presented in this document include security Some of the OAM tools presented in this document include security
mechanisms that provide integrity protection, thereby preventing mechanisms that provide integrity protection, thereby preventing
attackers from forging or tampering with OAM packets. For example, attackers from forging or tampering with OAM packets. For example,
[BFD] includes an optional authentication mechanism for BFD Control [BFD] includes an optional authentication mechanism for BFD Control
packets, using either SHA1, MD5, or a simple password. [OWAMP] and packets, using either SHA1, MD5, or a simple password. [OWAMP] and
[TWAMP] have 3 modes of security: unauthenticated, authenticated, [TWAMP] have three modes of security: unauthenticated, authenticated,
and encrypted. The authentication uses SHA1 as the HMAC algorithm, and encrypted. The authentication uses SHA1 as the HMAC algorithm,
and the encrypted mode uses AES encryption. and the encrypted mode uses AES encryption.
Confidentiality is typically not considered a requirement for OAM Confidentiality is typically not considered a requirement for OAM
protocols. However, the use of encryption (e.g., [OWAMP] and protocols. However, the use of encryption (e.g., [OWAMP] and
[TWAMP]) can make it difficult for attackers to identify OAM packets,
[TWAMP]) can make it difficult for attackers to identify OAM thus making it more difficult to attack the OAM protocol.
packets, thus making it more difficult to attack the OAM protocol.
OAM can also be used as a means for network reconnaissance; OAM can also be used as a means for network reconnaissance;
information about addresses, port numbers and about the network information about addresses, port numbers, and the network topology
topology and performance can be gathered either by passively and performance can be gathered by either passively eavesdropping on
eavesdropping to OAM packets, or by actively sending OAM packets and OAM packets or actively sending OAM packets and gathering information
gathering information from the respective responses. This from the respective responses. This information can then be used
information can then be used maliciously to attack the network. Note maliciously to attack the network. Note that some of this
that some of this information, e.g., addresses and port numbers, can information, e.g., addresses and port numbers, can be gathered even
be gather even when encryption is used ([OWAMP], [TWAMP]). when encryption is used ([OWAMP], [TWAMP]).
For further details about the security considerations of each OAM For further details about the security considerations of each OAM
protocol, the reader is encouraged to review the Security protocol, the reader is encouraged to review the Security
Considerations section of each document referenced by this memo. Considerations section of each document referenced by this memo.
7. IANA Considerations 7. Acknowledgments
There are no new IANA considerations implied by this document.
8. Acknowledgments
The authors gratefully acknowledge Sasha Vainshtein, Carlos The authors gratefully acknowledge Sasha Vainshtein, Carlos
Pignataro, David Harrington, Dan Romascanu, Ron Bonica, Benoit Pignataro, David Harrington, Dan Romascanu, Ron Bonica, Benoit
Claise, Stewart Bryant, Tom Nadeau, Elwyn Davies, Al Morton, Sam Claise, Stewart Bryant, Tom Nadeau, Elwyn Davies, Al Morton, Sam
Aldrin, Thomas Narten, and other members of the OPSA WG for their Aldrin, Thomas Narten, and other members of the OPSA WG for their
helpful comments on the mailing list. helpful comments on the mailing list.
This document was prepared using 2-Word-v2.0.template.dot. This document was originally prepared using 2-Word-v2.0.template.dot.
9. References 8. References
9.1. Normative References 8.1. Normative References
[OAM-Def] Andersson, L., Van Helvoort, H., Bonica, R., Romascanu, [OAM-Def] Andersson, L., van Helvoort, H., Bonica, R., Romascanu,
D., Mansfield, S., "Guidelines for the use of the OAM D., and S. Mansfield, "Guidelines for the Use of the
acronym in the IETF ", RFC 6291, June 2011. "OAM" Acronym in the IETF", BCP 161, RFC 6291, June
2011.
9.2. Informative References 8.2. Informative References
[ATM-L2] Singh, S., Townsley, M., and C. Pignataro, [ATM-L2] Singh, S., Townsley, M., and C. Pignataro,
"Asynchronous Transfer Mode (ATM) over Layer 2 "Asynchronous Transfer Mode (ATM) over Layer 2
Tunneling Protocol Version 3 (L2TPv3)", RFC 4454, May Tunneling Protocol Version 3 (L2TPv3)", RFC 4454, May
2006. 2006.
[BFD] Katz, D., Ward, D., "Bidirectional Forwarding Detection [BFD] Katz, D. and D. Ward, "Bidirectional Forwarding
(BFD)", RFC 5880, June 2010. Detection (BFD)", RFC 5880, June 2010.
[BFD-Gen] Katz, D., Ward, D., "Generic Application of [BFD-Gen] Katz, D. and D. Ward, "Generic Application of
Bidirectional Forwarding Detection (BFD)", RFC 5882, Bidirectional Forwarding Detection (BFD)", RFC 5882,
June 2010. June 2010.
[BFD-IP] Katz, D., Ward, D., "Bidirectional Forwarding Detection [BFD-IP] Katz, D. and D. Ward, "Bidirectional Forwarding
(BFD) for IPv4 and IPv6 (Single Hop)", RFC 5881, June Detection (BFD) for IPv4 and IPv6 (Single Hop)", RFC
2010. 5881, June 2010.
[BFD-LSP] Aggarwal, R., Kompella, K., Nadeau, T., and Swallow, [BFD-LSP] Aggarwal, R., Kompella, K., Nadeau, T., and G. Swallow,
G., "Bidirectional Forwarding Detection (BFD) for MPLS "Bidirectional Forwarding Detection (BFD) for MPLS
Label Switched Paths (LSPs)", RFC 5884, June 2010. Label Switched Paths (LSPs)", RFC 5884, June 2010.
[BFD-Multi] Katz, D., Ward, D., "Bidirectional Forwarding Detection [BFD-Multi] Katz, D. and D. Ward, "Bidirectional Forwarding
(BFD) for Multihop Paths", RFC 5883, June 2010. Detection (BFD) for Multihop Paths", RFC 5883, June
[BFD-VCCV] Nadeau, T., Pignataro, C., "Bidirectional Forwarding
Detection (BFD) for the Pseudowire Virtual Circuit
Connectivity Verification (VCCV)", RFC 5885, June
2010. 2010.
[BFD-VCCV] Nadeau, T., Ed., and C. Pignataro, Ed., "Bidirectional
Forwarding Detection (BFD) for the Pseudowire Virtual
Circuit Connectivity Verification (VCCV)", RFC 5885,
June 2010.
[Comp] Bonaventure, O., "Computer Networking: Principles, [Comp] Bonaventure, O., "Computer Networking: Principles,
Protocols and Practice", 2008. Protocols and Practice", 2008.
[Dup] Uijterwaal, H., "A One-Way Packet Duplication Metric", [Dup] Uijterwaal, H., "A One-Way Packet Duplication Metric",
RFC 5560, May 2009. RFC 5560, May 2009.
[Eth-Int] Mohan, D., Bitar, N., Sajassi, A., Delord, S., Niger, [Eth-Int] Mohan, D., Ed., Bitar, N., Ed., Sajassi, A., Ed.,
P., Qiu, R., "MPLS and Ethernet Operations, DeLord, S., Niger, P., and R. Qiu, "MPLS and Ethernet
Administration, and Maintenance (OAM) Interworking", Operations, Administration, and Maintenance (OAM)
RFC 7023, October 2013. Interworking", RFC 7023, October 2013.
[G-ACh] Bocci, M., Vigoureux, M., Bryant, S., "MPLS Generic [G-ACh] Bocci, M., Ed., Vigoureux, M., Ed., and S. Bryant, Ed.,
Associated Channel", RFC 5586, June 2009. "MPLS Generic Associated Channel", RFC 5586, June 2009.
[ICMP-Ext] Bonica, R., Gan, D., Tappan, D., Pignataro, C., "ICMP [ICMP-Ext] Bonica, R., Gan, D., Tappan, D., and C. Pignataro,
Extensions for Multiprotocol Label Switching", RFC "ICMP Extensions for Multiprotocol Label Switching",
4950, August 2007. RFC 4950, August 2007.
[ICMP-Int] Atlas, A., Bonica, R., Pignataro, C., Shen, N., Rivers, [ICMP-Int] Atlas, A., Ed., Bonica, R., Ed., Pignataro, C., Ed.,
JR., "Extending ICMP for Interface and Next-Hop Shen, N., and JR. Rivers, "Extending ICMP for Interface
Identification", RFC 5837, April 2010. and Next-Hop Identification", RFC 5837, April 2010.
[ICMP-MP] Bonica, R., Gan, D., Tappan, D., Pignataro, C., [ICMP-MP] Bonica, R., Gan, D., Tappan, D., and C. Pignataro,
"Extended ICMP to Support Multi-Part Messages", RFC "Extended ICMP to Support Multi-Part Messages", RFC
4884, April 2007. 4884, April 2007.
[ICMPv4] Postel, J., "Internet Control Message Protocol", STD 5, [ICMPv4] Postel, J., "Internet Control Message Protocol", STD 5,
RFC 792, September 1981. RFC 792, September 1981.
[ICMPv6] Conta, A., Deering, S., and M. Gupta, "Internet Control [ICMPv6] Conta, A., Deering, S., and M. Gupta, Ed., "Internet
Message Protocol (ICMPv6) for the Internet Protocol Control Message Protocol (ICMPv6) for the Internet
Version 6 (IPv6) Specification", RFC 4443, March 2006. Protocol Version 6 (IPv6) Specification", RFC 4443,
March 2006.
[IEEE802.1Q] IEEE 802.1Q, "IEEE Standard for Local and metropolitan [IEEE802.1Q] IEEE, "IEEE Standard for Local and metropolitan area
area networks - Media Access Control (MAC) Bridges and networks - Media Access Control (MAC) Bridges and
Virtual Bridged Local Area Networks", October 2012. Virtual Bridged Local Area Networks", IEEE 802.1Q,
October 2012.
[IEEE802.3ah] IEEE 802.3, "IEEE Standard for Information technology - [IEEE802.3ah] IEEE, "IEEE Standard for Information technology - Local
Local and metropolitan area networks - Carrier sense and metropolitan area networks - Carrier sense multiple
multiple access with collision detection (CSMA/CD) access with collision detection (CSMA/CD) access method
access method and physical layer specifications", and physical layer specifications", IEEE 802.3ah,
clause 57, December 2008. clause 57, December 2008.
[IntHost] Braden, R., "Requirements for Internet Hosts -- [IntHost] Braden, R., Ed., "Requirements for Internet Hosts -
Communication Layers", RFC 1122, October 1989. Communication Layers", STD 3, RFC 1122, October 1989.
[IPPM-1DM] Almes, G., Kalidindi, S., Zekauskas, M., "A One-way [IPPM-1DM] Almes, G., Kalidindi, S., and M. Zekauskas, "A One-way
Delay Metric for IPPM", RFC 2679, September 1999. Delay Metric for IPPM", RFC 2679, September 1999.
[IPPM-1LM] Almes, G., Kalidindi, S., Zekauskas, M., "A One-way [IPPM-1LM] Almes, G., Kalidindi, S., and M. Zekauskas, "A One-way
Packet Loss Metric for IPPM", RFC 2680, September Packet Loss Metric for IPPM", RFC 2680, September 1999.
1999.
[IPPM-2DM] Almes, G., Kalidindi, S., Zekauskas, M., "A Round-trip [IPPM-2DM] Almes, G., Kalidindi, S., and M. Zekauskas, "A Round-
Delay Metric for IPPM", RFC 2681, September 1999. trip Delay Metric for IPPM", RFC 2681, September 1999.
[IPPM-Con] Mahdavi, J., Paxson, V., "IPPM Metrics for Measuring [IPPM-Con] Mahdavi, J. and V. Paxson, "IPPM Metrics for Measuring
Connectivity", RFC 2678, September 1999. Connectivity", RFC 2678, September 1999.
[IPPM-FW] Paxson, V., Almes, G., Mahdavi, J., and Mathis, M., [IPPM-FW] Paxson, V., Almes, G., Mahdavi, J., and M. Mathis,
"Framework for IP Performance Metrics", RFC 2330, May "Framework for IP Performance Metrics", RFC 2330, May
1998. 1998.
[ITU-G8113.1] ITU-T Recommendation G.8113.1/Y.1372.1, "Operations, [ITU-G8113.1] ITU-T, "Operations, Administration and Maintenance
Administration and Maintenance mechanism for MPLS-TP mechanism for MPLS-TP in Packet Transport Network
in Packet Transport Network (PTN)", November 2012. (PTN)", ITU-T Recommendation G.8113.1/Y.1372.1,
November 2012.
[ITU-G8113.2] ITU-T Recommendation G.8113.2/Y.1372.2, "Operations, [ITU-G8113.2] ITU-T, "Operations, administration and maintenance
administration and maintenance mechanisms for MPLS-TP mechanisms for MPLS-TP networks using the tools defined
networks using the tools defined for MPLS", November for MPLS", ITU-T Recommendation G.8113.2/Y.1372.2,
2012. November 2012.
[ITU-T-CT] Betts, M., "Allocation of a Generic Associated Channel [ITU-T-CT] Betts, M., "Allocation of a Generic Associated Channel
Type for ITU-T MPLS Transport Profile Operation, Type for ITU-T MPLS Transport Profile Operation,
Maintenance, and Administration (MPLS-TP OAM)", RFC Maintenance, and Administration (MPLS-TP OAM)", RFC
6671, November 2012. 6671, November 2012.
[ITU-T-G.806] ITU-T Recommendation G.806, "Characteristics of [ITU-T-G.806] ITU-T, "Characteristics of transport equipment -
transport equipment - Description methodology and Description methodology and generic functionality",
generic functionality", January 2009. ITU-T Recommendation G.806, January 2009.
[ITU-T-Y1711] ITU-T Recommendation Y.1711, "Operation & Maintenance [ITU-T-Y1711] ITU-T, "Operation & Maintenance mechanism for MPLS
mechanism for MPLS networks", February 2004. networks", ITU-T Recommendation Y.1711, February 2004.
[ITU-T-Y1731] ITU-T Recommendation G.8013/Y.1731, "OAM Functions and [ITU-T-Y1731] ITU-T, "OAM Functions and Mechanisms for Ethernet-based
Mechanisms for Ethernet-based Networks", July 2011. Networks", ITU-T Recommendation G.8013/Y.1731, July
2011.
[ITU-Terms] ITU-R/ITU-T Terms and Definitions, online, 2013. [ITU-Terms] ITU-R/ITU-T, "ITU-R/ITU-T Terms and Definitions", 2013,
<http://www.itu.int/pub/R-TER-DB>.
[L2TP-EC] McGill, N. and C. Pignataro, "Layer 2 Tunneling [L2TP-EC] McGill, N. and C. Pignataro, "Layer 2 Tunneling
Protocol Version 3 (L2TPv3) Extended Circuit Status Protocol Version 3 (L2TPv3) Extended Circuit Status
Values", RFC 5641, August 2009. Values", RFC 5641, August 2009.
[L2VPN-OAM] Sajassi, A., Mohan, D., "Layer 2 Virtual Private [L2VPN-OAM] Sajassi, A., Ed., and D. Mohan, Ed., "Layer 2 Virtual
Network (L2VPN) Operations, Administration, and Private Network (L2VPN) Operations, Administration, and
Maintenance (OAM) Requirements and Framework", RFC Maintenance (OAM) Requirements and Framework", RFC
6136, March 2011. 6136, March 2011.
[L3VPN-OAM] El Mghazli, Y., Nadeau, T., Boucadair, M., Chan, K., [L3VPN-OAM] El Mghazli, Y., Ed., Nadeau, T., Boucadair, M., Chan,
Gonguet, A., "Framework for Layer 3 Virtual Private K., and A. Gonguet, "Framework for Layer 3 Virtual
Networks (L3VPN) Operations and Management", RFC 4176, Private Networks (L3VPN) Operations and Management",
October 2005. RFC 4176, October 2005.
[Lock-Loop] Boutros, S., Sivabalan, S., Aggarwal, R., Vigoureux, [Lock-Loop] Boutros, S., Ed., Sivabalan, S., Ed., Aggarwal, R.,
M., Dai, X., "MPLS Transport Profile Lock Instruct and Ed., Vigoureux, M., Ed., and X. Dai, Ed., "MPLS
Loopback Functions", RFC 6435, November 2011. Transport Profile Lock Instruct and Loopback
Functions", RFC 6435, November 2011.
[LSP-Ping] Kompella, K., Swallow, G., "Detecting Multi-Protocol [LSP-Ping] Kompella, K. and G. Swallow, "Detecting Multi-Protocol
Label Switched (MPLS) Data Plane Failures", RFC 4379, Label Switched (MPLS) Data Plane Failures", RFC 4379,
February 2006. February 2006.
[Mng] Farrel, A., "Inclusion of Manageability Sections in [Mng] Farrel, A., "Inclusion of Manageability Sections in
Path Computation Element (PCE) Working Group Drafts", Path Computation Element (PCE) Working Group Drafts",
RFC 6123, February 2011. RFC 6123, February 2011.
[MPLS-ENCAPS] Rosen, E., Tappan, D., Fedorkow, G., Rekhter, Y., [MPLS-ENCAPS] Rosen, E., Tappan, D., Fedorkow, G., Rekhter, Y.,
Farinacci, D., Li, T. and A. Conta, "MPLS Label Stack Farinacci, D., Li, T., and A. Conta, "MPLS Label Stack
Encoding", RFC 3032, January 2001. Encoding", RFC 3032, January 2001.
[MPLS-LM-DM] Frost, D., Bryant, S., "Packet Loss and Delay [MPLS-LM-DM] Frost, D. and S. Bryant, "Packet Loss and Delay
Measurement for MPLS Networks", RFC 6374, September Measurement for MPLS Networks", RFC 6374, September
2011. 2011.
[MPLS-OAM] Nadeau, T., Morrow, M., Swallow, G., Allan, D., [MPLS-OAM] Nadeau, T., Morrow, M., Swallow, G., Allan, D., and S.
Matsushima, S., "Operations and Management (OAM) Matsushima, "Operations and Management (OAM)
Requirements for Multi-Protocol Label Switched (MPLS) Requirements for Multi-Protocol Label Switched (MPLS)
Networks", RFC 4377, February 2006. Networks", RFC 4377, February 2006.
[MPLS-OAM-FW] Allan, D., Nadeau, T., "A Framework for Multi-Protocol [MPLS-OAM-FW] Allan, D., Ed., and T. Nadeau, Ed., "A Framework for
Label Switching (MPLS) Operations and Management Multi-Protocol Label Switching (MPLS) Operations and
(OAM)", RFC 4378, February 2006. Management (OAM)", RFC 4378, February 2006.
[MPLS-P2MP] Yasukawa, S., Farrel, A., King, D., Nadeau, T., [MPLS-P2MP] Yasukawa, S., Farrel, A., King, D., and T. Nadeau,
"Operations and Management (OAM) Requirements for "Operations and Management (OAM) Requirements for
Point-to-Multipoint MPLS Networks", RFC 4687, Point-to-Multipoint MPLS Networks", RFC 4687, September
September 2006. 2006.
[MPLS-TP-OAM] Vigoureux, M., Ward, D., Betts, M., "Requirements for [MPLS-TP-OAM] Vigoureux, M., Ed., Ward, D., Ed., and M. Betts, Ed.,
OAM in MPLS Transport Networks", RFC 5860, May 2010. "Requirements for Operations, Administration, and
Maintenance (OAM) in MPLS Transport Networks", RFC
5860, May 2010.
[mtrace] Fenner, W., Casner, S., "A "traceroute" facility for IP [mtrace] Fenner, W. and S. Casner, "A "traceroute" facility for
Multicast", draft-ietf-idmr-traceroute-ipm-07 IP Multicast", Work in Progress, July 2000.
(expired), July 2000.
[NetTerms] Jacobsen, O., Lynch, D., "A Glossary of Networking [NetTerms] Jacobsen, O. and D. Lynch, "A Glossary of Networking
Terms", RFC 1208, March 1991. Terms", RFC 1208, March 1991.
[NetTools] Enger, R., Reynolds, J., "FYI on a Network Management [NetTools] Enger, R. and J. Reynolds, "FYI on a Network Management
Tool Catalog: Tools for Monitoring and Debugging Tool Catalog: Tools for Monitoring and Debugging TCP/IP
TCP/IP Internets and Interconnected Devices", RFC Internets and Interconnected Devices", FYI 2, RFC 1470,
1470, June 1993. June 1993.
[OAM-Analys] Sprecher, N., Fang, L., "An Overview of the OAM Tool [OAM-Analys] Sprecher, N. and L. Fang, "An Overview of the
Set for MPLS based Transport Networks", RFC 6669, Operations, Administration, and Maintenance (OAM)
Toolset for MPLS-Based Transport Networks", RFC 6669,
July 2012. July 2012.
[OAM-Label] Ohta, H., "Assignment of the 'OAM Alert Label' for [OAM-Label] Ohta, H., "Assignment of the 'OAM Alert Label' for
Multiprotocol Label Switching Architecture (MPLS) Multiprotocol Label Switching Architecture (MPLS)
Operation and Maintenance (OAM) Functions", RFC 3429, Operation and Maintenance (OAM) Functions", RFC 3429,
November 2002. November 2002.
[OAM-Mng] Ersue, M., Claise, B., "An Overview of the IETF Network [OAM-Mng] Ersue, M., Ed., and B. Claise, "An Overview of the IETF
Management Standards", RFC 6632, June 2012. Network Management Standards", RFC 6632, June 2012.
[OnDemand-CV] Gray, E., Bahadur, N., Boutros, S., Aggarwal, R. "MPLS [OnDemand-CV] Gray, E., Bahadur, N., Boutros, S., and R. Aggarwal,
On-Demand Connectivity Verification and Route "MPLS On-Demand Connectivity Verification and Route
Tracing", RFC 6426, November 2011. Tracing", RFC 6426, November 2011.
[OWAMP] Shalunov, S., Teitelbaum, B., Karp, A., Boote, J., and [OWAMP] Shalunov, S., Teitelbaum, B., Karp, A., Boote, J., and
Zekauskas, M., "A One-way Active Measurement Protocol M. Zekauskas, "A One-way Active Measurement Protocol
(OWAMP)", RFC 4656, September 2006. (OWAMP)", RFC 4656, September 2006.
[PARIS] Brice Augustin, Timur Friedman and Renata Teixeira, [PARIS] Augustin, B., Friedman, T., and R. Teixeira, "Measuring
"Measuring Load-balanced Paths in the Internet", IMC, Load-balanced Paths in the Internet", IMC '07
2007. Proceedings of the 7th ACM SIGCOMM conference on
Internet measurement, 2007.
[PM-CONS] Clark, A. and B. Claise, "Guidelines for Considering [PM-CONS] Clark, A. and B. Claise, "Guidelines for Considering
New Performance Metric Development", BCP 170, RFC New Performance Metric Development", BCP 170, RFC 6390,
6390, October 2011. October 2011.
[PW-ACH] Bryant, S., Swallow, G., Martini, L., McPherson, D., [PW-ACH] Bryant, S., Swallow, G., Martini, L., and D. McPherson,
"Pseudowire Emulation Edge-to-Edge (PWE3) Control Word "Pseudowire Emulation Edge-to-Edge (PWE3) Control Word
for Use over an MPLS PSN", RFC 4385, February 2006. for Use over an MPLS PSN", RFC 4385, February 2006.
[PW-G-ACh] Li, H., Martini, L., He, J., Huang, F., "Using the [PW-G-ACh] Li, H., Martini, L., He, J., and F. Huang, "Using the
Generic Associated Channel Label for Pseudowire in the Generic Associated Channel Label for Pseudowire in the
MPLS Transport Profile (MPLS-TP)", RFC 6423, November MPLS Transport Profile (MPLS-TP)", RFC 6423, November
2011. 2011.
[PW-MAP] Aissaoui, M., Busschbach, P., Martini, L., Morrow, M., [PW-MAP] Aissaoui, M., Busschbach, P., Martini, L., Morrow, M.,
Nadeau, T., and Y(J). Stein, "Pseudowire (PW) Nadeau, T., and Y(J). Stein, "Pseudowire (PW)
Operations, Administration, and Maintenance (OAM) Operations, Administration, and Maintenance (OAM)
Message Mapping", RFC 6310, July 2011. Message Mapping", RFC 6310, July 2011.
[Reorder] Morton, A., Ciavattone, L., Ramachandran, G., Shalunov, [Reorder] Morton, A., Ciavattone, L., Ramachandran, G., Shalunov,
S., and J. Perser, "Packet Reordering Metrics", RFC S., and J. Perser, "Packet Reordering Metrics", RFC
4737, November 2006. 4737, November 2006.
[Signal] Yasukawa, S., "Signaling Requirements for Point-to- [Signal] Yasukawa, S., Ed., "Signaling Requirements for Point-
Multipoint Traffic-Engineered MPLS Label Switched to-Multipoint Traffic-Engineered MPLS Label Switched
Paths (LSPs)", RFC 4461, April 2006. Paths (LSPs)", RFC 4461, April 2006.
[TCPIP-Tools] Kessler, G., Shepard, S., "A Primer On Internet and [TCPIP-Tools] Kessler, G. and S. Shepard, "A Primer On Internet and
TCP/IP Tools and Utilities", RFC 2151, June 1997. TCP/IP Tools and Utilities", FYI 30, RFC 2151, June
1997.
[TP-CC-CV] Allan, D., Swallow, G., Drake, J., "Proactive [TP-CC-CV] Allan, D., Ed., Swallow Ed., G., and J. Drake Ed.,
Connectivity Verification, Continuity Check and Remote "Proactive Connectivity Verification, Continuity Check,
Defect indication for MPLS Transport Profile", RFC and Remote Defect Indication for the MPLS Transport
6428, November 2011. Profile", RFC 6428, November 2011.
[TP-Fault] Swallow, G., Fulignoli, A., Vigoureux, M., Boutros, S., [TP-Fault] Swallow, G., Ed., Fulignoli, A., Ed., Vigoureux, M.,
"MPLS Fault Management Operations, Administration, and Ed., Boutros, S., and D. Ward, "MPLS Fault Management
Maintenance (OAM)", RFC 6427, November 2011. Operations, Administration, and Maintenance (OAM)", RFC
6427, November 2011.
[TP-LM-DM] Frost, D., Bryant, S., "A Packet Loss and Delay [TP-LM-DM] Frost, D., Ed., and S. Bryant, Ed., "A Packet Loss and
Measurement Profile for MPLS-Based Transport Delay Measurement Profile for MPLS-Based Transport
Networks", RFC 6375, September 2011. Networks", RFC 6375, September 2011.
[TP-OAM-FW] Busi, I., Allan, D., "Operations, Administration and [TP-OAM-FW] Busi, I., Ed., and D. Allan, Ed., "Operations,
Maintenance Framework for MPLS-based Transport Administration, and Maintenance Framework for MPLS-
Networks ", RFC 6371, September 2011. Based Transport Networks", RFC 6371, September 2011.
[TP-Term] Van Helvoort, H., Andersson, L., Sprecher, N., "A [TP-Term] van Helvoort, H., Ed., Andersson, L., Ed., and N.
Thesaurus for the Terminology used in MPLS Transport Sprecher, Ed., "A Thesaurus for the Interpretation of
Profile (MPLS-TP) Internet-Drafts and RFCs in the Terminology Used in MPLS Transport Profile (MPLS-TP)
Context of the ITU-T's Transport Network Internet-Drafts and RFCs in the Context of the ITU-T's
Recommendations", RFC 7087, December 2013. Transport Network Recommendations", RFC 7087, December
2013.
[TRILL-OAM] Senevirathne, T., Bond, D., Aldrin, S., Li, Y., Watve, [TRILL-OAM] Senevirathne, T., Bond, D., Aldrin, S., Li, Y., and R.
R., "Requirements for Operations, Administration, and Watve, "Requirements for Operations, Administration,
Maintenance (OAM) in Transparent Interconnection of and Maintenance (OAM) in Transparent Interconnection of
Lots of Links (TRILL)", RFC 6905, March 2013. Lots of Links (TRILL)", RFC 6905, March 2013.
[TWAMP] Hedayat, K., Krzanowski, R., Morton, A., Yum, K., and [TWAMP] Hedayat, K., Krzanowski, R., Morton, A., Yum, K., and
Babiarz, J., "A Two-Way Active Measurement Protocol J. Babiarz, "A Two-Way Active Measurement Protocol
(TWAMP)", RFC 5357, October 2008. (TWAMP)", RFC 5357, October 2008.
[VCCV] Nadeau, T., Pignataro, C., "Pseudowire Virtual Circuit [VCCV] Nadeau, T., Ed., and C. Pignataro, Ed., "Pseudowire
Connectivity Verification (VCCV): A Control Channel Virtual Circuit Connectivity Verification (VCCV): A
for Pseudowires", RFC 5085, December 2007. Control Channel for Pseudowires", RFC 5085, December
2007.
[VCCV-SURVEY] Del Regno, N., Malis, A., "The Pseudowire (PW) and [VCCV-SURVEY] Del Regno, N., Ed., and A. Malis, Ed., "The Pseudowire
Virtual Circuit Connectivity Verification (VCCV) (PW) and Virtual Circuit Connectivity Verification
Implementation Survey Results", RFC 7079, November (VCCV) Implementation Survey Results", RFC 7079,
2013. November 2013.
Appendix A. List of OAM Documents Appendix A. List of OAM Documents
A.1. List of IETF OAM Documents A.1. List of IETF OAM Documents
Table 5 summarizes the OAM related RFCs published by the IETF. Table 5 summarizes the OAM-related RFCs produced by the IETF.
It is important to note that the table lists various RFCs that are It is important to note that the table lists various RFCs that are
different by nature. For example, some of these documents define OAM different by nature. For example, some of these documents define OAM
tools or OAM protocols (or both), while others define protocols that tools or OAM protocols (or both), while others define protocols that
are not strictly OAM-related, but are used by OAM tools. The table are not strictly OAM related, but are used by OAM tools. The table
also includes RFCs that define the requirements or the framework of also includes RFCs that define the requirements or the framework of
OAM in a specific context (e.g., MPLS-TP). OAM in a specific context (e.g., MPLS-TP).
The RFCs in the table are categorized in a few sets as defined in The RFCs in the table are categorized in a few sets as defined in
Section 1.3. Section 1.3.
+-----------+--------------------------------------+----------+ +-----------+--------------------------------------+----------+
| Toolset | Title | RFC | | Toolset | Title | RFC |
+-----------+--------------------------------------+----------+ +-----------+--------------------------------------+----------+
|IP Ping | Requirements for Internet Hosts -- | RFC 1122 | |IP Ping | Requirements for Internet Hosts -- | RFC 1122 |
skipping to change at page 45, line 9 skipping to change at page 47, line 12
| | Version 6 (IPv6) Specification | | | | Version 6 (IPv6) Specification | |
| | [ICMPv6] | | | | [ICMPv6] | |
| +--------------------------------------+----------+ | +--------------------------------------+----------+
| | Extended ICMP to Support Multi-Part | RFC 4884 | | | Extended ICMP to Support Multi-Part | RFC 4884 |
| | Messages [ICMP-MP] | | | | Messages [ICMP-MP] | |
| +--------------------------------------+----------+ | +--------------------------------------+----------+
| | Extending ICMP for Interface and | RFC 5837 | | | Extending ICMP for Interface and | RFC 5837 |
| | Next-Hop Identification [ICMP-Int] | | | | Next-Hop Identification [ICMP-Int] | |
+-----------+--------------------------------------+----------+ +-----------+--------------------------------------+----------+
|BFD | Bidirectional Forwarding Detection | RFC 5880 | |BFD | Bidirectional Forwarding Detection | RFC 5880 |
| | [BFD] | | | | (BFD) [BFD] | |
| +--------------------------------------+----------+ | +--------------------------------------+----------+
| | Bidirectional Forwarding Detection | RFC 5881 | | | Bidirectional Forwarding Detection | RFC 5881 |
| | (BFD) for IPv4 and IPv6 (Single Hop) | | | | (BFD) for IPv4 and IPv6 (Single Hop) | |
| | [BFD-IP] | | | | [BFD-IP] | |
| +--------------------------------------+----------+ | +--------------------------------------+----------+
| | Generic Application of Bidirectional | RFC 5882 | | | Generic Application of Bidirectional | RFC 5882 |
| | Forwarding Detection [BFD-Gen] | | | | Forwarding Detection (BFD)[BFD-Gen] | |
| +--------------------------------------+----------+ | +--------------------------------------+----------+
| | Bidirectional Forwarding Detection | RFC 5883 | | | Bidirectional Forwarding Detection | RFC 5883 |
| | (BFD) for Multihop Paths [BFD-Multi] | | | | (BFD) for Multihop Paths [BFD-Multi] | |
| +--------------------------------------+----------+ | +--------------------------------------+----------+
| | Bidirectional Forwarding Detection | RFC 5884 | | | Bidirectional Forwarding Detection | RFC 5884 |
| | for MPLS Label Switched Paths (LSPs) | | | | (BFD) for MPLS Label Switched Paths | |
| | [BFD-LSP] | | | | (LSPs) [BFD-LSP] | |
| +--------------------------------------+----------+ | +--------------------------------------+----------+
| | Bidirectional Forwarding Detection | RFC 5885 | | | Bidirectional Forwarding Detection | RFC 5885 |
| | for the Pseudowire Virtual Circuit | | | | for the Pseudowire Virtual Circuit | |
| | Connectivity Verification (VCCV) | | | | Connectivity Verification (VCCV) | |
| | [BFD-VCCV] | | | | [BFD-VCCV] | |
+-----------+--------------------------------------+----------+ +-----------+--------------------------------------+----------+
|MPLS OAM | Operations and Management (OAM) | RFC 4377 | |MPLS OAM | Operations and Management (OAM) | RFC 4377 |
| | Requirements for Multi-Protocol Label| | | | Requirements for Multi-Protocol Label| |
| | Switched (MPLS) Networks [MPLS-OAM] | | | | Switched (MPLS) Networks [MPLS-OAM] | |
| +--------------------------------------+----------+ | +--------------------------------------+----------+
skipping to change at page 46, line 12 skipping to change at page 48, line 9
| | Requirements for Point-to-Multipoint | | | | Requirements for Point-to-Multipoint | |
| | MPLS Networks [MPLS-P2MP] | | | | MPLS Networks [MPLS-P2MP] | |
| +--------------------------------------+----------+ | +--------------------------------------+----------+
| | ICMP Extensions for Multiprotocol | RFC 4950 | | | ICMP Extensions for Multiprotocol | RFC 4950 |
| | Label Switching [ICMP-Ext] | | | | Label Switching [ICMP-Ext] | |
| +--------------------------------------+----------+ | +--------------------------------------+----------+
| | Bidirectional Forwarding Detection | RFC 5884 | | | Bidirectional Forwarding Detection | RFC 5884 |
| | for MPLS Label Switched Paths (LSPs) | | | | for MPLS Label Switched Paths (LSPs) | |
| | [BFD-LSP] | | | | [BFD-LSP] | |
+-----------+--------------------------------------+----------+ +-----------+--------------------------------------+----------+
|MPLS-TP | Requirements for OAM in MPLS-TP | RFC 5860 | |MPLS-TP | Requirements for Operations, | RFC 5860 |
|OAM | [MPLS-TP-OAM] | | |OAM | Administration, and Maintenance (OAM)| |
| | in MPLS Transport Networks | |
| | [MPLS-TP-OAM] | |
| +--------------------------------------+----------+ | +--------------------------------------+----------+
| | MPLS Generic Associated Channel | RFC 5586 | | | MPLS Generic Associated Channel | RFC 5586 |
| | [G-ACh] | | | | [G-ACh] | |
| +--------------------------------------+----------+ | +--------------------------------------+----------+
| | MPLS-TP OAM Framework | RFC 6371 | | | Operations, Administration, and | RFC 6371 |
| | [TP-OAM-FW] | | | | Maintenance Framework for MPLS-Based | |
| | Transport Networks [TP-OAM-FW] | |
| +--------------------------------------+----------+ | +--------------------------------------+----------+
| | Proactive Connectivity Verification, | RFC 6428 | | | Proactive Connectivity Verification, | RFC 6428 |
| | Continuity Check, and Remote Defect | | | | Continuity Check, and Remote Defect | |
| | Indication for the MPLS Transport | | | | Indication for the MPLS Transport | |
| | Profile [TP-CC-CV] | | | | Profile [TP-CC-CV] | |
| +--------------------------------------+----------+ | +--------------------------------------+----------+
| | MPLS On-Demand Connectivity | RFC 6426 | | | MPLS On-Demand Connectivity | RFC 6426 |
| | Verification and Route Tracing | | | | Verification and Route Tracing | |
| | [OnDemand-CV] | | | | [OnDemand-CV] | |
| +--------------------------------------+----------+ | +--------------------------------------+----------+
skipping to change at page 47, line 27 skipping to change at page 49, line 24
| +--------------------------------------+----------+ | +--------------------------------------+----------+
| | Pseudowire (PW) Operations, | RFC 6310 | | | Pseudowire (PW) Operations, | RFC 6310 |
| | Administration, and Maintenance (OAM)| | | | Administration, and Maintenance (OAM)| |
| | Message Mapping [PW-MAP] | | | | Message Mapping [PW-MAP] | |
| +--------------------------------------+----------+ | +--------------------------------------+----------+
| | MPLS and Ethernet Operations, | RFC 7023 | | | MPLS and Ethernet Operations, | RFC 7023 |
| | Administration, and Maintenance (OAM)| | | | Administration, and Maintenance (OAM)| |
| | Interworking [Eth-Int] | | | | Interworking [Eth-Int] | |
+-----------+--------------------------------------+----------+ +-----------+--------------------------------------+----------+
|OWAMP and | A One-way Active Measurement Protocol| RFC 4656 | |OWAMP and | A One-way Active Measurement Protocol| RFC 4656 |
|TWAMP | [OWAMP] | | |TWAMP | (OWAMP) [OWAMP] | |
| +--------------------------------------+----------+ | +--------------------------------------+----------+
| | A Two-Way Active Measurement Protocol| RFC 5357 | | | A Two-Way Active Measurement Protocol| RFC 5357 |
| | [TWAMP] | | | | (TWAMP) [TWAMP] | |
| +--------------------------------------+----------+ | +--------------------------------------+----------+
| | Framework for IP Performance Metrics | RFC 2330 | | | Framework for IP Performance Metrics | RFC 2330 |
| | [IPPM-FW] | | | | [IPPM-FW] | |
| +--------------------------------------+----------+ | +--------------------------------------+----------+
| | IPPM Metrics for Measuring | RFC 2678 | | | IPPM Metrics for Measuring | RFC 2678 |
| | Connectivity [IPPM-Con] | | | | Connectivity [IPPM-Con] | |
| +--------------------------------------+----------+ | +--------------------------------------+----------+
| | A One-way Delay Metric for IPPM | RFC 2679 | | | A One-way Delay Metric for IPPM | RFC 2679 |
| | [IPPM-1DM] | | | | [IPPM-1DM] | |
| +--------------------------------------+----------+ | +--------------------------------------+----------+
skipping to change at page 48, line 17 skipping to change at page 50, line 10
| | [Reorder] | | | | [Reorder] | |
| +--------------------------------------+----------+ | +--------------------------------------+----------+
| | A One-Way Packet Duplication Metric | RFC 5560 | | | A One-Way Packet Duplication Metric | RFC 5560 |
| | [Dup] | | | | [Dup] | |
+-----------+--------------------------------------+----------+ +-----------+--------------------------------------+----------+
|TRILL OAM | Requirements for Operations, | RFC 6905 | |TRILL OAM | Requirements for Operations, | RFC 6905 |
| | Administration, and Maintenance (OAM)| | | | Administration, and Maintenance (OAM)| |
| | in Transparent Interconnection of | | | | in Transparent Interconnection of | |
| | Lots of Links (TRILL) | | | | Lots of Links (TRILL) | |
+-----------+--------------------------------------+----------+ +-----------+--------------------------------------+----------+
Table 5 Summary of IETF OAM Related RFCs
A.2. List of Selected Non-IETF OAM Documents Table 5: Summary of IETF OAM-Related RFCs
A.2. List of Selected Non-IETF OAM Documents
In addition to the OAM tools defined by the IETF, the IEEE and ITU-T In addition to the OAM tools defined by the IETF, the IEEE and ITU-T
have also defined various OAM tools that focus on Ethernet, and have also defined various OAM tools that focus on Ethernet and
various other transport network environments. These various tools, various other transport-network environments. These various tools,
defined by the three standard organizations, are often tightly defined by the three standard organizations, are often tightly
coupled, and have had a mutual effect on each other. The ITU-T and coupled and have had a mutual effect on each other. The ITU-T and
IETF have both defined OAM tools for MPLS LSPs, [ITU-T-Y1711] and IETF have both defined OAM tools for MPLS LSPs, [ITU-T-Y1711], and
[LSP-Ping]. The following OAM standards by the IEEE and ITU-T are to [LSP-Ping]. The following OAM standards by the IEEE and ITU-T are to
some extent linked to IETF OAM tools listed above and are mentioned some extent linked to the IETF OAM tools listed above and are
here only as reference material: mentioned here only as reference material.
o OAM tools for Layer 2 have been defined by the ITU-T in o OAM tools for Layer 2 have been defined by the ITU-T in
[ITU-T-Y1731], and by the IEEE in 802.1ag [IEEE802.1Q] . The IEEE [ITU-T-Y1731] and by the IEEE in 802.1ag [IEEE802.1Q]. The IEEE
802.3 standard defines OAM for one-hop Ethernet links 802.3 standard defines OAM for one-hop Ethernet links
[IEEE802.3ah]. [IEEE802.3ah].
o The ITU-T has defined OAM for MPLS LSPs in [ITU-T-Y1711], and o The ITU-T has defined OAM for MPLS LSPs in [ITU-T-Y1711] and for
MPLS-TP OAM in [ITU-G8113.1] and [ITU-G8113.2]. MPLS-TP OAM in [ITU-G8113.1] and [ITU-G8113.2].
It should be noted that these non-IETF documents deal in many cases It should be noted that these non-IETF documents deal in many cases
with OAM functions below the IP layer (Layer 2, Layer 2.5) and in with OAM functions below the IP layer (Layer 2, Layer 2.5) and that
some cases operators use a multi-layered OAM approach, which is a in some cases operators use a multi-layered OAM approach, which is a
function of the way their networks are designed. function of the way their networks are designed.
Table 6 summarizes some of the main OAM standards published by non- Table 6 summarizes some of the main OAM standards published by
IETF standard organizations. This document focuses on IETF OAM non-IETF standard organizations. This document focuses on IETF OAM
standards, but these non-IETF standards are referenced in this standards, but these non-IETF standards are referenced in this
document where relevant. document where relevant.
+-----------+--------------------------------------+---------------+ +-----------+--------------------------------------+---------------+
| | Title |Standard/Draft | | | Title | Document |
+-----------+--------------------------------------+---------------+ +-----------+--------------------------------------+---------------+
|ITU-T | Operation & Maintenance mechanism | ITU-T Y.1711 | |ITU-T | Operation & Maintenance mechanism | ITU-T Y.1711 |
|MPLS OAM | for MPLS networks [ITU-T-Y1711] | | |MPLS OAM | for MPLS networks [ITU-T-Y1711] | |
| +--------------------------------------+---------------+ | +--------------------------------------+---------------+
| | Assignment of the 'OAM Alert Label' | RFC 3429 | | | Assignment of the 'OAM Alert Label' | RFC 3429 |
| | for Multiprotocol Label Switching | | | | for Multiprotocol Label Switching | |
| | Architecture (MPLS) Operation and | | | | Architecture (MPLS) Operation and | |
| | Maintenance (OAM) Functions | | | | Maintenance (OAM) Functions | |
| | [OAM-Label] | | | | [OAM-Label] | |
| | | | | | | |
skipping to change at page 50, line 16 skipping to change at page 52, line 25
| | of ITU-T G.8113.1. | | | | of ITU-T G.8113.1. | |
+-----------+--------------------------------------+---------------+ +-----------+--------------------------------------+---------------+
|ITU-T | OAM Functions and Mechanisms for | ITU-T Y.1731 | |ITU-T | OAM Functions and Mechanisms for | ITU-T Y.1731 |
|Ethernet | Ethernet-based Networks | | |Ethernet | Ethernet-based Networks | |
|OAM | [ITU-T-Y1731] | | |OAM | [ITU-T-Y1731] | |
+-----------+--------------------------------------+---------------+ +-----------+--------------------------------------+---------------+
|IEEE | Connectivity Fault Management | IEEE 802.1ag | |IEEE | Connectivity Fault Management | IEEE 802.1ag |
|CFM | [IEEE802.1Q] | | |CFM | [IEEE802.1Q] | |
| | | | | | | |
| | Note: CFM was originally published | | | | Note: CFM was originally published | |
| | as IEEE 802.1ag, but is now | | | | as IEEE 802.1ag but is now | |
| | incorporated in the 802.1Q standard.| | | | incorporated in the 802.1Q standard.| |
+-----------+--------------------------------------+---------------+ +-----------+--------------------------------------+---------------+
|IEEE | Management of Data Driven and Data | IEEE 802.1ag | |IEEE | Management of Data Driven and Data | IEEE 802.1ag |
|DDCFM | Dependent Connectivity Faults | | |DDCFM | Dependent Connectivity Faults | |
| | [IEEE802.1Q] | | | | [IEEE802.1Q] | |
| | | | | | | |
| | Note: DDCFM was originally published| | | | Note: DDCFM was originally published| |
| | as IEEE 802.1Qaw, but is now | | | | as IEEE 802.1Qaw but is now | |
| | incorporated in the 802.1Q standard.| | | | incorporated in the 802.1Q standard.| |
+-----------+--------------------------------------+---------------+ +-----------+--------------------------------------+---------------+
|IEEE | Media Access Control Parameters, | IEEE 802.3ah | |IEEE | Media Access Control Parameters, | IEEE 802.3ah |
|802.3 | Physical Layers, and Management | | |802.3 | Physical Layers, and Management | |
|link level | Parameters for Subscriber Access | | |link level | Parameters for Subscriber Access | |
|OAM | Networks [IEEE802.3ah] | | |OAM | Networks [IEEE802.3ah] | |
| | | | | | | |
| | Note: link level OAM was originally | | | | Note: link level OAM was originally | |
| | defined in IEEE 802.3ah, and is now | | | | defined in IEEE 802.3ah and is now | |
| | incorporated in the 802.3 standard. | | | | incorporated in the 802.3 standard. | |
+-----------+--------------------------------------+---------------+ +-----------+--------------------------------------+---------------+
Table 6 Non-IETF OAM Standards Mentioned in this Document
Table 6: Non-IETF OAM Standards Mentioned in This Document
Authors' Addresses Authors' Addresses
Tal Mizrahi Tal Mizrahi
Marvell Marvell
6 Hamada St. 6 Hamada St.
Yokneam, 20692 Yokneam 20692
Israel Israel
Email: talmi@marvell.com EMail: talmi@marvell.com
Nurit Sprecher Nurit Sprecher
Nokia Solutions and Networks Nokia Solutions and Networks
3 Hanagar St. Neve Ne'eman B 3 Hanagar St. Neve Ne'eman B
Hod Hasharon, 45241 Hod Hasharon 45241
Israel Israel
Email: nurit.sprecher@nsn.com EMail: nurit.sprecher@nsn.com
Elisa Bellagamba Elisa Bellagamba
Ericsson Ericsson
6 Farogatan St. 6 Farogatan St.
Stockholm, 164 40 Stockholm 164 40
Sweden Sweden
Phone: +46 761440785 Phone: +46 761440785
Email: elisa.bellagamba@ericsson.com EMail: elisa.bellagamba@ericsson.com
Yaacov Weingarten Yaacov Weingarten
34 Hagefen St. 34 Hagefen St.
Karnei Shomron, 4485500 Karnei Shomron 4485500
Israel Israel
Email: wyaacov@gmail.com EMail: wyaacov@gmail.com
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