draft-ietf-opsawg-oam-overview-09.txt   draft-ietf-opsawg-oam-overview-10.txt 
Operations and Management Area Working Group T. Mizrahi Operations and Management Area Working Group T. Mizrahi
Internet Draft Marvell Internet Draft Marvell
Intended status: Informational N. Sprecher Intended status: Informational N. Sprecher
Expires: January 2014 Nokia Siemens Networks Expires: April 2014 Nokia Siemens Networks
E. Bellagamba E. Bellagamba
Ericsson Ericsson
Y. Weingarten Y. Weingarten
July 9, 2013 October 21, 2013
An Overview of An Overview of Operations, Administration, and Maintenance (OAM)
Operations, Administration, and Maintenance (OAM) Mechanisms Data Plane Tools
draft-ietf-opsawg-oam-overview-09.txt draft-ietf-opsawg-oam-overview-10.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. OAM mechanisms have been defined for various performance measurement. Over the years various OAM tools have been
layers in the protocol stack, and are used with a variety of defined for various layers in the protocol stack.
transport protocols.
This document presents an overview of the data plane OAM tools that This document summarizes some of the data plane OAM tools defined in
have been defined by the IETF. the IETF in the context of IP unicast, MPLS, pseudowires, MPLS for
the transport profile (MPLS-TP), and TRILL.
The target audience of this document includes network equipment
vendors, network operators and standard development organizations,
and can be used as an index to some of the main data plane OAM tools
defined in the IETF.
Status of this Memo Status of this Memo
This Internet-Draft is submitted to IETF in full conformance with the This Internet-Draft is submitted to IETF in full conformance with the
provisions of BCP 78 and BCP 79. provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents of the Internet Engineering Internet-Drafts are working documents of the Internet Engineering
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other groups may also distribute working documents as Internet- other groups may also distribute working documents as Internet-
Drafts. Drafts.
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and may be updated, replaced, or obsoleted by other documents at any and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress." material or to cite them other than as "work in progress."
The list of current Internet-Drafts can be accessed at The list of current Internet-Drafts can be accessed at
http://www.ietf.org/ietf/1id-abstracts.txt. http://www.ietf.org/ietf/1id-abstracts.txt.
The list of Internet-Draft Shadow Directories can be accessed at The list of Internet-Draft Shadow Directories can be accessed at
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This Internet-Draft will expire on January 9, 2014. This Internet-Draft will expire on April 21, 2014.
Copyright Notice Copyright Notice
Copyright (c) 2013 IETF Trust and the persons identified as the Copyright (c) 2013 IETF Trust and the persons identified as the
document authors. All rights reserved. document authors. All rights reserved.
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described in the Simplified BSD License. described in the Simplified BSD License.
Table of Contents Table of Contents
1. Introduction ................................................. 3 1. Introduction ................................................. 3
1.1. Background .............................................. 4 1.1. Background .............................................. 4
1.2. Target Audience.......................................... 4 1.2. Target Audience.......................................... 5
1.3. OAM-related Work in the IETF ............................ 5 1.3. OAM-related Work in the IETF ............................ 5
1.4. Focusing on Data Plane OAM Tools ........................ 6 1.4. Focusing on Data Plane OAM Tools ........................ 6
2. Terminology .................................................. 6 2. Terminology .................................................. 7
2.1. Abbreviations ........................................... 6 2.1. Abbreviations ........................................... 7
2.2. Terminology used in OAM Standards ....................... 8 2.2. Terminology used in OAM Standards ....................... 9
2.2.1. General Terms ...................................... 8 2.2.1. General Terms ...................................... 9
2.2.2. Functions, Mechanisms, Tools and Protocols ......... 8 2.2.2. Operations, Administration and Maintenance ......... 9
2.2.3. Data Plane, Control Plane and Management Plane ..... 9 2.2.3. Functions, Tools and Protocols ..................... 9
2.2.4. The Players ....................................... 10 2.2.4. Data Plane, Control Plane and Management Plane .... 10
2.2.5. Proactive and On-demand Activation ................ 11 2.2.5. The Players ....................................... 11
2.2.6. Connectivity Verification and Continuity Checks ... 11 2.2.6. Proactive and On-demand Activation ................ 12
2.2.7. Failures .......................................... 12 2.2.7. Connectivity Verification and Continuity Checks ... 12
3. OAM Functions ............................................... 12 2.2.8. Connection Oriented vs. Connectionless Communication13
4. OAM Mechanisms in the IETF - a Detailed Description.......... 13 2.2.9. Point-to-point vs. Point-to-multipoint Services ... 14
4.1. IP Ping ................................................ 13 2.2.10. Failures ......................................... 14
4.2. IP Traceroute .......................................... 14 3. OAM Functions ............................................... 15
4.3. Bidirectional Forwarding Detection (BFD) ............... 15 4. OAM Tools in the IETF - a Detailed Description .............. 16
4.3.1. Overview .......................................... 15 4.1. IP Ping ................................................ 16
4.3.2. Terminology ....................................... 15 4.2. IP Traceroute .......................................... 16
4.3.3. BFD Control ....................................... 15 4.3. Bidirectional Forwarding Detection (BFD) ............... 17
4.3.4. BFD Echo .......................................... 16 4.3.1. Overview .......................................... 17
4.4. MPLS OAM ............................................... 16 4.3.2. Terminology ....................................... 18
4.5. MPLS-TP OAM ............................................ 17 4.3.3. BFD Control ....................................... 18
4.5.1. Overview .......................................... 17 4.3.4. BFD Echo .......................................... 18
4.5.2. Terminology ....................................... 17 4.4. MPLS OAM ............................................... 19
4.5.3. Generic Associated Channel ........................ 19 4.5. MPLS-TP OAM ............................................ 20
4.5.4. MPLS-TP OAM Toolset ............................... 19 4.5.1. Overview .......................................... 20
4.5.4.1. Continuity Check and Connectivity Verification 20 4.5.2. Terminology ....................................... 20
4.5.4.2. Route Tracing ................................ 20 4.5.3. Generic Associated Channel ........................ 22
4.5.4.3. Lock Instruct ................................ 20 4.5.4. MPLS-TP OAM Toolset ............................... 22
4.5.4.4. Lock Reporting ............................... 21 4.5.4.1. Continuity Check and Connectivity Verification 23
4.5.4.5. Alarm Reporting .............................. 21 4.5.4.2. Route Tracing ................................ 23
4.5.4.6. Remote Defect Indication ..................... 21 4.5.4.3. Lock Instruct ................................ 23
4.5.4.7. Client Failure Indication .................... 21 4.5.4.4. Lock Reporting ............................... 24
4.5.4.8. Performance Monitoring ....................... 21 4.5.4.5. Alarm Reporting .............................. 24
4.5.4.8.1. Packet Loss Measurement (LM) ............ 22 4.5.4.6. Remote Defect Indication ..................... 24
4.5.4.8.2. Packet Delay Measurement (DM) ........... 22 4.5.4.7. Client Failure Indication .................... 24
4.6. Pseudowire OAM ......................................... 23 4.5.4.8. Performance Monitoring ....................... 24
4.5.4.8.1. Packet Loss Measurement (LM) ............ 24
4.5.4.8.2. Packet Delay Measurement (DM) ........... 25
4.6. Pseudowire OAM ......................................... 26
4.6.1. Pseudowire OAM using Virtual Circuit Connectivity 4.6.1. Pseudowire OAM using Virtual Circuit Connectivity
Verification (VCCV) ...................................... 23 Verification (VCCV) ...................................... 26
4.6.2. Pseudowire OAM using G-ACh ........................ 24 4.6.2. Pseudowire OAM using G-ACh ........................ 27
4.6.3. Attachment Circuit - Pseudowire Mapping ........... 24 4.6.3. Attachment Circuit - Pseudowire Mapping ........... 27
4.7. OWAMP and TWAMP......................................... 24 4.7. OWAMP and TWAMP......................................... 27
4.7.1. Overview .......................................... 24 4.7.1. Overview .......................................... 27
4.7.2. Control and Test Protocols ........................ 25 4.7.2. Control and Test Protocols ........................ 28
4.7.3. OWAMP ............................................. 25 4.7.3. OWAMP ............................................. 28
4.7.4. TWAMP ............................................. 26 4.7.4. TWAMP ............................................. 29
4.8. TRILL .................................................. 26 4.8. TRILL .................................................. 29
4.9. Summary of OAM Mechanisms .............................. 27 4.9. Summary of OAM Tools ................................... 30
4.10. Summary of OAM Functions .............................. 29 4.10. Summary of OAM Functions .............................. 32
5. Security Considerations ..................................... 30 5. Security Considerations ..................................... 33
6. IANA Considerations ......................................... 31 6. IANA Considerations ......................................... 34
7. Acknowledgments ............................................. 31 7. Acknowledgments ............................................. 34
8. References .................................................. 31 8. References .................................................. 34
8.1. Informative References ................................. 31 8.1. Informative References ................................. 34
Appendix A. List of OAM Documents .............................. 36 Appendix A. List of OAM Documents .............................. 40
A.1. List of IETF OAM Documents ............................. 36 A.1. List of IETF OAM Documents ............................. 40
A.2. List of Selected Non-IETF OAM Documents ................ 41 A.2. List of Selected Non-IETF OAM Documents ................ 44
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 the network
performance. performance.
There are several different interpretations to the "OAM" acronym. There are several different interpretations to the "OAM" acronym.
This document refers to Operations, Administration and Maintenance, This document refers to Operations, Administration and Maintenance,
as recommended in [OAM-Def]. as recommended in Section 3 of [RFC6291].
This document summarizes the OAM tools and mechanisms defined in the This document summarizes some of the data plane OAM tools defined in
IETF. This document focuses on data plane OAM tools. Hence, control the IETF in the context of IP unicast, MPLS, pseudowires, MPLS for
and management aspects of OAM are outside the scope of this document. the transport profile (MPLS-TP), and TRILL.
This document focuses on data plane OAM tools. Hence, control and
management aspects of OAM are outside the scope of this document.
This document focuses on tools for detecting and isolating failures
and for performance monitoring. Network repair functions such as Fast
Reroute (FRR) and protection switching, which are often triggered by
OAM protocols, are out of the scope of this document.
1.1. Background 1.1. Background
OAM was originally used in traditional transport technologies such as OAM was originally used in traditional communication technologies
E1 and T1, evolving into PDH and then later in SONET/SDH. ATM was such as E1 and T1, evolving into PDH and then later in SONET/SDH. ATM
probably the first technology to include inherent OAM mechanisms from was probably the first technology to include inherent OAM support
day one, while in other transport technologies OAM was typically from day one, while in other technologies OAM was typically defined
defined in an ad hoc manner after the technology was already defined in an ad hoc manner after the technology was already defined and
and deployed. Packet-based networks were traditionally considered deployed. Packet-based networks were traditionally considered
unreliable and best-effort, but as packet-based networks evolved, unreliable and best-effort, but as packet-based networks evolved,
they have become the common transport for both data and telephony, they have become the common transport for both data and telephony,
replacing traditional transport protocols. Consequently, packet-based replacing traditional transport protocols. Consequently, packet-based
networks were expected to provide a similar "carrier grade" networks were expected to provide a similar "carrier grade"
experience, and specifically to support OAM. experience, and specifically to support OAM.
OAM typically has a multi-layer architecture; each transport As typical networks have a multi-layer architecture, the set of OAM
technology has its own OAM mechanisms. Moreover, OAM can be used at protocols similarly take a multi-layer structure; each layer has its
different levels of hierarchy in the network to form a multi-layer own OAM protocols. Moreover, OAM can be used at different levels of
OAM solution, as shown in the example in Figure 1. hierarchy in the network to form a multi-layer OAM solution, as shown
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 OAM
is used at the provider-level for monitoring the connection between is used at the provider-level for monitoring the connection between
the two provider edges, while IP OAM is used at the customer-level the two provider edges, while IP OAM is used at the customer-level
for monitoring the end-to-end connection between the two customer for monitoring the end-to-end connection between the two customer
edges. edges.
|<-------------- Customer-level OAM -------------->| |<-------------- Customer-level OAM -------------->|
IP OAM (Ping, Traceroute, OWAMP, TWAMP) IP OAM (Ping, Traceroute, OWAMP, TWAMP)
skipping to change at page 5, line 8 skipping to change at page 5, line 28
Figure 1 Example: Multi-layer OAM Figure 1 Example: 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 Standard development organizations - both IETF working groups and o Standard 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
mechanisms for new transport 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 existing IETF OAM mechanisms, and their document as an index to some of the common IETF OAM tools.
connection to various transport technologies.
It should be noted that this document is not necessarily suitable for It should be noted that this document is not necessarily suitable for
beginners without any background in OAM. beginners without any background in OAM.
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 This memo provides an overview of the different sets of OAM tools
mechanisms defined by the IETF. The set of OAM mechanisms described defined by the IETF. The set of OAM tools described in this memo are
in this memo are applicable to IP unicast, MPLS, pseudowires, MPLS applicable to IP unicast, MPLS, pseudowires, MPLS for the transport
for the transport profile (MPLS-TP), and TRILL. While OAM mechanisms profile (MPLS-TP), and TRILL. While OAM tools that are applicable to
that are applicable to other technologies exist, they are beyond the other technologies exist, they are beyond the scope of this memo.
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 mechanisms in several The IETF has defined OAM protocols and tools in several different
different contexts. We roughly categorize these efforts into a few contexts. We roughly categorize these efforts into a few sets of OAM-
sets of OAM-related RFCs, listed in Table 1. Each category defines a related RFCs, listed in Table 1. Each category defines a logically-
logically-coupled set of RFCs, although the sets are in some cases coupled set of RFCs, although the sets are in some cases intertwined
intertwined by common tools and protocols. by common tools and protocols.
The discussion in this document is ordered according to these The discussion in this document is ordered according to these
categories. categories.
+--------------+------------+ +--------------+------------+
| Category | Transport | | Category | Transport |
| | Technology | | | Technology |
+--------------+------------+ +--------------+------------+
|IP Ping | IPv4/IPv6 | |IP Ping | IPv4/IPv6 |
+--------------+------------+ +--------------+------------+
skipping to change at page 6, line 18 skipping to change at page 6, line 36
|OWAMP and | IPv4/IPv6 | |OWAMP and | IPv4/IPv6 |
|TWAMP | | |TWAMP | |
+--------------+------------+ +--------------+------------+
|TRILL OAM | TRILL | |TRILL OAM | TRILL |
+--------------+------------+ +--------------+------------+
Table 1 Categories of OAM-related IETF Documents Table 1 Categories of OAM-related IETF Documents
1.4. Focusing on Data Plane OAM Tools 1.4. Focusing on Data Plane OAM Tools
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. The OAM tools communicate with the plane and/or management plane. At the data plane, OAM provides
management plane to raise alarms, and often OAM tools may be instrumentation tools. OAM tools often use control plane functions,
activated by the management (as well as by the control plane), e.g. e.g., to initialize OAM sessions and to exchange various parameters.
to locate and localize problems. The OAM tools communicate with the management plane to raise alarms,
and often OAM tools may be activated by the management (as well as by
the control plane), 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. are used for OAM. Network repair functions such as Fast Reroute (FRR)
and protection switching, which are often triggered by OAM 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 in as much accuracy as possible. Thus, it is important to plane in as much accuracy as possible. Thus, it is important to
enforce fate-sharing between OAM traffic and the user-traffic it enforce fate-sharing between OAM traffic that monitors the data plane
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
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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 CV Connectivity Verification
DM Delay Measurement DM Delay Measurement
ECMP Equal Cost Multiple Paths
FEC Forwarding Equivalence Class FEC Forwarding Equivalence Class
FRR Fast Reroute
G-ACh Generic Associated Channel G-ACh Generic Associated Channel
GAL Generic Associated Label GAL Generic Associated Label
ICMP Internet Control Message Protocol ICMP Internet Control Message Protocol
L2TP Layer Two Tunneling Protocol L2TP Layer Two Tunneling Protocol
LCCE L2TP Control Connection Endpoint LCCE L2TP Control Connection Endpoint
skipping to change at page 8, line 33 skipping to change at page 9, line 18
A wide variety of terms is used in various OAM standards. This 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], and provides a good summary of some of the
OAM related terminology. OAM related terminology.
2.2.2. Functions, Mechanisms, Tools and Protocols 2.2.2. Operations, Administration and Maintenance
The following definition of OAM is quoted from [OAM-Def]:
The components of the "OAM" acronym (and provisioning) are defined as
follows:
o Operations - Operation activities are undertaken to keep the
network (and the services that the network provides) up and
running. It includes monitoring the network and finding problems.
Ideally these problems should be found before users are affected.
o Administration - Administration activities involve keeping track
of resources in the network and how they are used. It includes
all the bookkeeping that is necessary to track networking
resources and the network under control.
o Maintenance - Maintenance activities are focused on facilitating
repairs and upgrades -- for example, when equipment must be
replaced, when a router needs a patch for an operating system
image, or when a new switch is added to a network. Maintenance
also involves corrective and preventive measures to make the
managed network run more effectively, e.g., adjusting device
configuration and parameters.
2.2.3. Functions, Tools and Protocols
OAM Function OAM Function
OAM is a group of functions that provide network fault indication, An OAM function is an instrumentation measurement type or diagnostic.
performance information, and data and diagnosis functions (based on
the definition of OAM in the ATM Forum Glossary).
This definition implies that OAM functions are the atomic building OAM functions are the atomic building blocks of OAM, where each
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. 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 Mechanism OAM Tool
An OAM Mechanism, sometimes referred to as an OAM tool, is a An OAM tool is a specific means of applying one or more OAM
mechanism that implements one or more OAM functions. functions.
In some cases an OAM protocol *is* an OAM mechanism, e.g., OWAMP- In some cases an OAM protocol *is* an OAM tool, e.g., OWAMP-Test. In
Test. In other cases an OAM mechanism uses a set of protocols that other cases an OAM tool uses a set of protocols that are not strictly
are not strictly OAM-related; for example, Traceroute (Section 4.2.) OAM-related; for example, Traceroute (Section 4.2.) can be
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.
The terms tool and mechanism are used interchangeably in this 2.2.4. Data Plane, Control Plane and Management Plane
document.
2.2.3. Data Plane, Control Plane and Management Plane
Data Plane Data Plane
The Data Plane is typically described as the hardware and software The data plane is the set of functions used to transfer data in the
components responsible for receiving a packet, performing lookups to stratum or layer under consideration [ITU-Terms].
identify the packet's destination and possible actions that need to
be performed on the packet, and forwarding the packet out through the .
appropriate outgoing interface (based on [Cont]).
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, as described in [Cont], is generally described as The control plane is the set of protocols and mechanisms that enable
the hardware and software components for handling packets destined to routers to efficiently learn how to forward packets towards their
the device itself as well as building and sending packets originated final destination (based on [Comp]).
locally on the device.
Management Plane Management Plane
This term Management Plane, as described in [Mgmt], is used to The term Management Plane, as described in [Mng], is used to describe
describe the exchange of management messages through management the exchange of management messages through management protocols
protocols (often transported by IP and by IP transport protocols) (often transported by IP and by IP transport protocols) between
between management applications and the managed entities such as management applications and the managed entities such as network
network nodes. 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 OAM
tools such as ping, BFD and others are in fact in the control plane. tools such as ping, BFD and others are in fact in the control plane.
This document focuses on data plane OAM tools, i.e., tools used for This document focuses on data plane OAM tools, i.e., tools used for
monitoring the data plane. While these tools could arguably be monitoring the data plane. While these tools could arguably be
considered to be in the control plane, these tools monitor the data considered to be in the control plane, these tools monitor the data
plane, and hence it is imperative to have fate-sharing between OAM plane, and hence it is imperative to have fate-sharing between OAM
traffic and the data plane traffic it monitors. traffic that 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 plane
and control plane. The management plane should be seen as separate and control plane. The management plane should be seen as separate
from, but possibly overlapping with, the control plane (based on from, but possibly overlapping with, the control plane (based on
[Mgmt]). [Mng]).
2.2.4. The Players 2.2.5. The Players
An OAM mechanism is used between two (or more) "players". Various An OAM tool is used between two (or more) "players". Various terms
terms are used in IETF documents to refer to the players that take are used in IETF documents to refer to the players that take part in
part in OAM. Table 2 summarizes the terms used in each of the OAM. Table 2 summarizes the terms used in each of the categories
categories discussed in this document. discussed in this document.
+--------------------------+--------------------------+ +--------------------------+--------------------------+
| Category | Terms | | Category | 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 |
skipping to change at page 11, line 5 skipping to change at page 12, line 10
| 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 Table 2 Maintenance Point Terminology
2.2.5. Proactive and On-demand Activation 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 Proactive activation - indicates that the tool is activated on a
continual basis, where messages are sent periodically, and errors are continual basis, where messages are sent periodically, and errors are
detected when a certain number of expected messages are not received. detected when a certain number of expected messages are not received.
On-demand On-demand
On-demand activation - indicates that the tool is activated On-demand activation - indicates that the tool is activated
"manually" to detect a specific anomaly. "manually" to detect a specific anomaly.
2.2.6. Connectivity Verification and Continuity Checks 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 reachable,
and are typically sent proactively, though they can be invoked on- and are typically sent proactively, though they can be invoked on-
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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 either in the control plane or in 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 originator.
A CV function can be applied proactively or on-demand. A CV function can be applied proactively or on-demand.
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 each
other. other.
2.2.7. Failures 2.2.8. Connection Oriented vs. Connectionless Communication
Connection Oriented
In Connection Oriented technologies an end-to-end connection is
established (by a control protocol or provisioned by a management
system) prior to the transmission of data.
Typically a connection identifier is used to identify the connection.
In connection oriented technologies it is often the case (although
not always) that all packets belonging to a specific connection use
the same route through the network.
Connectionless
In Connectionless technologies data is typically sent between end
points without prior arrangement. Packets are routed independently
based on their destination address, and hence different packets may
be routed in a different way across the network.
Discussion
The OAM tools described in this document include tools that support
connection oriented technologies, as well as tools for connectionless
technologies.
In connection oriented technologies OAM is used to monitor a
*specific* connection; OAM packets are forwarded through the same
route as the data traffic and receive the same treatment. In
connectionless technologies, OAM is used between a source and
destination pair without defining a specific connection. Moreover, in
some cases the route of OAM packets may differ from the one of the
data traffic. For example, the connectionless IP Ping (Section 4.1.)
tests the reachability from a source to a given destination, while
the connection oriented LSP Ping (Section 4.4.) is used for
monitoring a specific LSP (connection), and provides the capability
to monitor all the available paths used by an LSP.
It should be noted that in some cases connectionless protocols are
monitored by connection oriented OAM protocols. For example, while IP
is a connectionless protocol, it can monitored by BFD (Section 4.3.
), which is connection oriented.
2.2.9. Point-to-point vs. Point-to-multipoint Services
Point-to-point (P2P)
A P2P service delivers data from a single source to a single
destination.
Point-to-multipoint (P2MP)
An P2MP service delivers data from a single source to a one or more
destinations (based on [Signal]).
[Signal] also defines a MP2MP service as a service that delivers data
from more than one source to one or more receivers.
Discussion
The OAM tools described in this document include tools for P2P
services, as well as tools for P2MP services.
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 end points. P2MP 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. Another challenge in P2MP
services is performance monitoring; while in P2P packet loss is
measured by maintaining packet counters at the two end-points, in
P2MP packet loss must be carefully measured by generating synthetic
traffic to each corresponding end-point and maintaining a separate
counter for each peer end-point.
2.2.10. Failures
The terms Failure, Fault, and Defect are used interchangeably in the The terms Failure, Fault, and Defect are used interchangeably in the
standards, referring to a malfunction that can be detected by a standards, referring to a malfunction that can be detected by a
connectivity or a continuity check. In some standards, such as connectivity or a continuity check. In some standards, such as
802.1ag [IEEE802.1Q] , there is no distinction between these terms, 802.1ag [IEEE802.1Q] , there is no distinction between these terms,
while in other standards each of these terms refers to a different while in other standards each of these terms refers to a different
type of malfunction. type of malfunction.
The terminology used in IETF MPLS-TP OAM takes after the ITU-T, which The terminology used in IETF MPLS-TP OAM is based on the ITU-T
distinguishes between these terms in [ITU-T-G.806]; terminology, which distinguishes between these three terms in
[ITU-T-G.806];
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
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While a Defect typically refers to a limited period of time, a While a Defect typically refers to a limited period of time, a
failure refers to a long period of time. 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) and/or Continuity Checks (CC): o Connectivity Verification (CV) and/or Continuity Checks (CC):
As defined in Section 2.2.6. As defined in Section 2.2.7.
o Path Discovery / Fault Localization: o Path Discovery / Fault Localization:
This mechanism 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 mechanism traces one of the available routes. When a failure this function traces one of the available routes. When a failure
occurs, this mechanism also allows to detect the location of the occurs, this function also allows 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) that is used in
the context of IP and MPLS, is sometimes referred to as path the context of IP and MPLS, is sometimes referred to as path
tracing in other transport technologies, such as TRILL. 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. o Loss Measurement (LM) - monitors the packet loss rate.
o Delay Measurement (DM) - monitors the delay and delay o Delay Measurement (DM) - monitors the delay and delay
variation. variation.
4. OAM Mechanisms 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 mechanisms in each of the categories in Table 1. related tools in each of the categories 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 diagnosis application for IP networks that
uses ICMP. 'Ping' is an abbreviation for Packet internet groper uses ICMP. According to [NetTerms], 'Ping' is an abbreviation for
[NetTerms]. As defined in [NetTerms], it is a program used to test Packet internet groper, although the term has been so commonly used
reachability of destinations by sending them an ICMP echo request and that it stands on its own. As defined in [NetTerms], it is a program
waiting for a reply. used to test reachability of destinations by sending them an ICMP
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 an
ICMP Echo request packet, and the receiver replies with an Echo 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 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.
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packets, each with the TTL value of 2. These messages cause the packets, each with the TTL value of 2. These messages cause the
second router to return ICMP messages. This process continues, with second router to return ICMP messages. This process continues, with
ever increasing values for the TTL field, until the packets actually ever increasing values for the TTL field, until the packets actually
reach the destination. Because no application listens to port 33434 reach the destination. Because no application listens to port 33434
at the destination, the destination returns ICMP Destination at the destination, the destination returns ICMP Destination
Unreachable Messages indicating an unreachable port. This event Unreachable Messages indicating an unreachable port. This event
indicates to the Traceroute application that it is finished. The indicates to the Traceroute application that it is finished. The
Traceroute program displays the round-trip delay associated with each Traceroute program displays the round-trip delay associated with each
of the attempts. of the attempts.
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
Cost Multiple Paths (ECMP). Paris Traceroute [Paris] is an extension
to Traceroute that attempts to discovers all the available paths from
A to B by scanning different values of header fields (such as UDP
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. As
such, it has various different implementations. One of the most 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 extensions,
including extensions to the ICMP Destination Unreachable message, including extensions to the ICMP Destination Unreachable message,
that can be used by Traceroute applications. that can be used by Traceroute applications.
4.3. Bidirectional Forwarding Detection (BFD) 4.3. Bidirectional Forwarding Detection (BFD)
4.3.1. Overview 4.3.1. Overview
While multiple OAM mechanisms have been defined for various protocols While multiple OAM tools have been defined for various protocols in
in the protocol stack, Bidirectional Forwarding Detection [BFD], the protocol stack, Bidirectional Forwarding Detection [BFD], defined
defined by the IETF BFD working group, is a generic OAM mechanism by the IETF BFD working group, is a generic OAM tool that can be
that can be deployed over various encapsulating protocols, and in deployed over various encapsulating protocols, and in various medium
various medium types. The IETF has defined variants of the protocol types. The IETF has defined variants of the protocol for IP ([BFD-
for IP ([BFD-IP], [BFD-Multi]), for MPLS LSPs [BFD-LSP], and for IP], [BFD-Multi]), for MPLS LSPs [BFD-LSP], and for pseudowires [BFD-
pseudowires [BFD-VCCV]. The usage of BFD in MPLS-TP is defined in VCCV]. The usage of BFD in MPLS-TP is defined in [TP-CC-CV].
[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 two *systems*. The BFD protocol is run between BFD operates between two *systems*. The BFD protocol is run between
two systems after establishing a *session*. two systems after establishing a *session*.
4.3.3. BFD Control 4.3.3. BFD Control
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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 is not used in BFD for MPLS LSPs, PWs, or in BFD for
MPLS-TP. 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
mechanism defined, in this context, is LSP Ping [LSP-Ping]. tool defined, in this context, is LSP Ping [LSP-Ping]. OAM for P2MP
services is defined in [MPLS-P2MP].
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 extends the basic ICMP Ping operation (of data-plane LSP Ping extends the basic ICMP Ping operation (of data-plane
connectivity verification) with functionality to verify data-plane connectivity verification) with functionality to verify data-plane
vs. control-plane consistency for a Forwarding Equivalence Class vs. control-plane consistency for a Forwarding Equivalence Class
(FEC) and also Maximum Transmission Unit (MTU) problems. The (FEC) and also Maximum Transmission Unit (MTU) problems.
Traceroute functionality may be used to isolate and localize the MPLS
faults, using the Time-to-live (TTL) indicator to incrementally 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
monitors all the available paths of an LSP by monitoring its
different Forwarding Equivalence Classes (FEC). Conversely, MPLS-TP
does not use ECMP, and thus does not require OAM over multiple paths.
The Traceroute functionality may be used to isolate and localize the
MPLS 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.
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 easily extensible to using the full FEC identification. LSP Ping is easily extensible to
include additional information needed to support new functionality, include additional information needed to support new functionality,
by use of Type-Length-Value (TLV) constructs. The usage of TLVs is by use of Type-Length-Value (TLV) constructs. The usage of TLVs is
typically not easy to perform in hardware, and is thus typically typically not easy to perform in hardware, and is thus typically
handled by the control plane. handled by the control plane.
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LSP Ping supports both asynchronous, as well as, on-demand LSP Ping supports both asynchronous, as well as, on-demand
activation. activation.
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 MPLS-
TP OAM are defined in [MPLS-TP-OAM], and include both general TP OAM are defined in [MPLS-TP-OAM], and include both general
requirements for the behavior of the OAM mechanisms 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 as well as
giving overviews of the functionality of the OAM toolset. giving 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 and non-IP
based environment. If the network is IP based, i.e. IP routing and based environment. If the network is IP based, i.e. IP routing and
forwarding are available, then the MPLS-TP OAM toolset should rely forwarding are available, then the MPLS-TP OAM toolset should rely
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payload follows immediately after the label stack. 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
mechanisms and their ability to fulfill the required functionality. tools and their ability to fulfill the required functionality. The
The conclusions of this analysis are documented in [OAM-Analys]. The conclusions of this analysis are documented in [OAM-Analys]. The MPLS
MPLS working group currently plans to use a mixture of OAM mechanisms working group currently plans to use a mixture of OAM tools that are
that are based on various existing standards, and adapt them to the based on various existing standards, and adapt them to the
requirements of [MPLS-TP-OAM]. Some of the main building blocks of requirements of [MPLS-TP-OAM]. Some of the main building blocks of
this solution are based on: 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
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o Performance measurement protocols that are based on the o Performance measurement protocols that are based on the
functionality that is described in [ITU-T-Y1731]. functionality that is described in [ITU-T-Y1731].
The following sub-sections describe the OAM tools defined for MPLS-TP The following sub-sections 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 Check and Connectivity Verification are presented in
Section 2.2.6. 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
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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: end-points 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. that packet by the destination node. Note that one-way delay
measurement requires the clocks of the two end-points to be
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 loop-backed packet by the same source node, when the loopback is
performed at the packet's destination node. performed at the packet's destination node. Note that due to
possible path asymmetry, the one-way packet delay from one end-
point to another is not necessarily equal to half of the two-way
packet delay.
As opposed to one-way delay measurement, two-way delay measurement
does not require the two end-points to be 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 measurement
is performed by exchanging timestamped OAM packets between the is performed by exchanging timestamped OAM packets between the
participating MEPs. 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)
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o CC Type 2: Out-of-band VCCV [VCCV], is also referred to as "MPLS o CC Type 2: Out-of-band VCCV [VCCV], is also referred to as "MPLS
Router Alert Label". In this case the control channel is created Router Alert Label". In this case the control channel is created
by using the MPLS router alert label [RFC3032] immediately above by using the MPLS router alert label [RFC3032] immediately above
the PW label. the PW label.
o CC Type 3: TTL expiry VCCV [VCCV], is also referred to as "MPLS PW o CC Type 3: TTL expiry VCCV [VCCV], is also referred to as "MPLS PW
Label with TTL == 1", i.e., the control channel is identified when Label with TTL == 1", i.e., the control channel is identified when
the value of the TTL field in the PW label is set to 1. the value of the TTL field in the PW label is set to 1.
VCCV currently supports the following OAM mechanisms: ICMP Ping, LSP VCCV currently supports the following OAM tools: ICMP Ping, LSP Ping,
Ping, and BFD. ICMP and LSP Ping are IP encapsulated before being and BFD. ICMP and LSP Ping are IP encapsulated before being sent over
sent over the PW ACH. BFD for VCCV [BFD-VCCV] supports two modes of 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 to
signal the AC status. The use of the VCCV control channel provides signal the AC status. The use of the VCCV control channel provides
the context, based on the MPLS-PW label, required to bind and the context, based on the MPLS-PW label, required to bind and
bootstrap the BFD session to a particular pseudo wire (FEC), bootstrap the BFD session to a particular pseudo wire (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) signaled component to
communicate VCCV capabilities as part of VC label, and (2) switching communicate VCCV capabilities as part of VC label, and (2) switching
component to cause the PW payload to be treated as a control packet. 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 negotiation may be performed as part of the PW The VCCV capability negotiation 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
[VCCV-SURVEY], which analyzes which VCCV mechanisms are used in
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
skipping to change at page 26, line 42 skipping to change at page 29, line 44
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 mode is negotiated as in
OWAMP. The Control-Client then requests sessions and starts them. 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 insertion of
timestamps. timestamps.
4.8. TRILL 4.8. TRILL
The requirements of OAM in TRILL are defined in [TRILL-OAM]. The main The requirements of OAM in TRILL are defined in [TRILL-OAM]. The
challenge in TRILL OAM is that traffic between RBridges RB1 and RB2 challenge in TRILL OAM, much like in MPLS networks, is that traffic
may be forwarded through more than one path. Thus, an OAM protocol between RBridges RB1 and RB2 may be forwarded through more than one
between RBridges RB1 and RB2 must be able to monitor all the path. Thus, an OAM protocol between RBridges RB1 and RB2 must be able
available paths between the two RBridge. to monitor all the available paths between the two RBridge.
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 are 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.
4.9. Summary of OAM Mechanisms 4.9. Summary of OAM Tools
This subsection provides a short summary of each of the OAM mechanism This subsection provides a short summary of each of the OAM tool
categories described in this document. categories described in this document.
A detailed list of the RFCs related to each category is given in A detailed list of the RFCs related to each category is given in
Appendix A.1. Appendix A.1.
+-----------+------------------------------------------+------------+ +-----------+------------------------------------------+------------+
| Category | Description | Transport | | Category | Description | Transport |
| | | Technology | | | | Technology |
+-----------+------------------------------------------+------------+ +-----------+------------------------------------------+------------+
|IP Ping | Ping ([IntHost], [NetTerms]) is a simple | IPv4/IPv6 | |IP Ping | Ping ([IntHost], [NetTerms]) is a simple | IPv4/IPv6 |
skipping to change at page 28, line 5 skipping to change at page 31, line 9
| | 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 destination| |
| | Traceroute traces *a* path. The most | | | | Traceroute traces *a* path. The most | |
| | common implementation of Traceroute | | | | common implementation of Traceroute | |
| | uses UDP probe messages, although there | | | | uses UDP probe messages, although there | |
| | are other implementations that use | | | | are other implementations that use | |
| | different probes, such as ICMP or TCP. | | | | different probes, such as ICMP or TCP. | |
+-----------+------------------------------------------+------------+ +-----------+------------------------------------------+------------+
|BFD | Bidirectional Forwarding Detection (BFD) | generic | |BFD | Bidirectional Forwarding Detection (BFD) | generic |
| | is defined in [BFD] as a framework for a | | | | is defined in [BFD] as a framework for a | |
| | lightweight generic OAM mechanism. The | | | | lightweight generic OAM tool. The | |
| | intention is to define a base mechanism | | | | intention is to define a base tool | |
| | that can be used with various | | | | that can be used with various | |
| | encapsulation types, network | | | | encapsulation types, network | |
| | environments, and in various medium | | | | environments, and in various medium | |
| | types. | | | | types. | |
+-----------+------------------------------------------+------------+ +-----------+------------------------------------------+------------+
|MPLS OAM | MPLS LSP Ping, as defined in [MPLS-OAM], | MPLS | |MPLS OAM | MPLS LSP Ping, as defined in [MPLS-OAM], | MPLS |
| | [MPLS-OAM-FW] and [LSP-Ping], is an OAM | | | | [MPLS-OAM-FW] and [LSP-Ping], is an OAM | |
| | mechanism for point-to-point and | | | | tool for point-to-point and | |
| | point-to-multipoint MLPS LSPs. | | | | point-to-multipoint MLPS LSPs. | |
| | It includes two main functions: Ping and | | | | It includes two main functions: Ping and | |
| | Traceroute. | | | | Traceroute. | |
| | It is noted that while this category | | | | It is noted that while this category | |
| | focuses on LSP Ping, other OAM mechanisms| | | | focuses on LSP Ping, other OAM tools | |
| | can be used in MPLS networks, e.g., BFD. | | | | can be used in MPLS networks, e.g., BFD. | |
+-----------+------------------------------------------+------------+ +-----------+------------------------------------------+------------+
|MPLS-TP OAM| MPLS-TP OAM is defined in a set of RFCs. | MPLS-TP | |MPLS-TP OAM| MPLS-TP OAM is defined in a set of RFCs. | MPLS-TP |
| | The OAM requirements for MPLS Transport | | | | The OAM requirements for MPLS Transport | |
| | Profile (MPLS-TP) are defined in | | | | Profile (MPLS-TP) are defined in | |
| | [MPLS-TP-OAM]. Each of the tools in the | | | | [MPLS-TP-OAM]. Each of the tools in the | |
| | OAM toolset is defined in its own RFC, as| | | | OAM toolset is defined in its own RFC, as| |
| | specified in Section A.1. | | | | specified in Section A.1. | |
+-----------+------------------------------------------+------------+ +-----------+------------------------------------------+------------+
|Pseudowire | The PWE3 OAM architecture defines control| Pseudowire | |Pseudowire | The PWE3 OAM architecture defines control| Pseudowire |
skipping to change at page 29, line 19 skipping to change at page 32, line 23
+-----------+------------------------------------------+------------+ +-----------+------------------------------------------+------------+
|TRILL OAM | The requirements of OAM in TRILL are | TRILL | |TRILL OAM | The requirements of OAM in TRILL are | TRILL |
| | defined in [TRILL-OAM]. These | | | | defined in [TRILL-OAM]. These | |
| | requirements include continuity checking,| | | | requirements include continuity checking,| |
| | connectivity verification, path tracing | | | | connectivity verification, path tracing | |
| | and performance monitoring. During the | | | | and performance monitoring. During the | |
| | writing of this document the detailed | | | | writing of this document the detailed | |
| | definition of the TRILL OAM tools | | | | definition of the TRILL OAM tools | |
| | is work in progress. | | | | is work in progress. | |
+-----------+------------------------------------------+------------+ +-----------+------------------------------------------+------------+
Table 3 Summary of OAM-related IETF Mechanisms Table 3 Summary of OAM-related IETF Tools
4.10. Summary of OAM Functions 4.10. 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 categories that were analyzed in this section. The columns of the categories that were analyzed in this section. The columns of
this tables are the typical OAM functions described in Section 1.3. this tables are the typical OAM functions described in Section 1.3.
+-----------+-------+--------+--------+-------+----------+ +-----------+-------+--------+--------+-------+----------+
| |Continu|Connecti|Path |Perform|Other | | |Continu|Connecti|Path |Perform|Other |
| |ity |vity |Discover|ance |Function | | |ity |vity |Discover|ance |Function |
skipping to change at page 30, line 36 skipping to change at page 33, line 40
| | | | ement | | | | | | ement | |
+ --------- + ----- + ------ + ------ + ----- + -------- + + --------- + ----- + ------ + ------ + ----- + -------- +
|TRILL OAM |CC |CV |Path |-Delay | | |TRILL OAM |CC |CV |Path |-Delay | |
| | | |tracing | measur| | | | | |tracing | measur| |
| | | | | ement | | | | | | | ement | |
| | | | |-Packet| | | | | | |-Packet| |
| | | | | loss | | | | | | | loss | |
| | | | | measur| | | | | | | measur| |
| | | | | ement | | | | | | | ement | |
+-----------+-------+--------+--------+-------+----------+ +-----------+-------+--------+--------+-------+----------+
Table 4 Summary of the OAM Functionality in IETF OAM Mechanisms Table 4 Summary of the OAM Functionality in IETF OAM Tools
5. Security Considerations 5. Security Considerations
This memo presents an overview of existing OAM mechanisms, and This memo presents an overview of existing OAM tools, and proposes
proposes no new OAM mechanisms. Therefore, this document introduces no new OAM tools. Therefore, this document introduces no security
no security considerations. However, the OAM mechanism reviewed in considerations. However, the OAM tools reviewed in this document can
this document can and do present security issues. The reader is and do present security issues. The reader is encouraged to review
encouraged to review the Security Considerations section of each the Security Considerations section of each document referenced by
document referenced by this memo. this memo.
6. IANA Considerations 6. IANA Considerations
There are no new IANA considerations implied by this document. There are no new IANA considerations implied by this document.
7. Acknowledgments 7. Acknowledgments
The authors gratefully acknowledge Sasha Vainshtein, Carlos The authors gratefully acknowledge Sasha Vainshtein, Carlos
Pignataro, David Harrington, Dan Romascanu, Ron Bonica and other Pignataro, David Harrington, Dan Romascanu, Ron Bonica and other
members of the OPSAWG mailing list for their helpful comments. members of the OPSAWG mailing list for their helpful comments.
This document was prepared using 2-Word-v2.0.template.dot. This document was prepared using 2-Word-v2.0.template.dot.
8. References 8. References
8.1. Informative References 8.1. Informative References
[LSP-Ping] Kompella, K., Swallow, G., "Detecting Multi-Protocol
Label Switched (MPLS) Data Plane Failures", RFC 4379,
February 2006.
[MPLS-OAM] Nadeau, T., Morrow, M., Swallow, G., Allan, D.,
Matsushima, S., "Operations and Management (OAM)
Requirements for Multi-Protocol Label Switched (MPLS)
Networks", RFC 4377, February 2006.
[MPLS-OAM-FW] Allan, D., Nadeau, T., "A Framework for Multi-Protocol
Label Switching (MPLS) Operations and Management
(OAM)", RFC 4378, February 2006.
[OAM-Label] Ohta, H., "Assignment of the 'OAM Alert Label' for
Multiprotocol Label Switching Architecture (MPLS)
Operation and Maintenance (OAM) Functions", RFC 3429,
November 2002.
[MPLS-TP-OAM] Vigoureux, M., Ward, D., Betts, M., "Requirements for
OAM in MPLS Transport Networks", RFC 5860, May 2010.
[G-ACh] Bocci, M., Vigoureux, M., Bryant, S., "MPLS Generic
Associated Channel", RFC 5586, June 2009.
[VCCV] Nadeau, T., Pignataro, C., "Pseudowire Virtual Circuit
Connectivity Verification (VCCV): A Control Channel
for Pseudowires", RFC 5085, December 2007.
[PW-ACH] Bryant, S., Swallow, G., Martini, L., McPherson, D.,
"Pseudowire Emulation Edge-to-Edge (PWE3) Control Word
for Use over an MPLS PSN", RFC 4385, February 2006.
[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.
[L2TP-EC] McGill, N. and C. Pignataro, "Layer 2 Tunneling [BFD] Katz, D., Ward, D., "Bidirectional Forwarding Detection
Protocol Version 3 (L2TPv3) Extended Circuit Status (BFD)", RFC 5880, June 2010.
Values", RFC 5641, August 2009.
[PW-MAP] Aissaoui, M., Busschbach, P., Martini, L., Morrow, M., [BFD-Gen] Katz, D., Ward, D., "Generic Application of
Nadeau, T., and Y(J). Stein, "Pseudowire (PW) Bidirectional Forwarding Detection (BFD)", RFC 5882,
Operations, Administration, and Maintenance (OAM) June 2010.
Message Mapping", RFC 6310, July 2011.
[ICMPv4] Postel, J., "Internet Control Message Protocol", STD 5, [BFD-IP] Katz, D., Ward, D., "Bidirectional Forwarding Detection
RFC 792, September 1981. (BFD) for IPv4 and IPv6 (Single Hop)", RFC 5881, June
2010.
[ICMPv6] Conta, A., Deering, S., and M. Gupta, "Internet Control [BFD-LSP] Aggarwal, R., Kompella, K., Nadeau, T., and Swallow,
Message Protocol (ICMPv6) for the Internet Protocol G., "Bidirectional Forwarding Detection (BFD) for MPLS
Version 6 (IPv6) Specification", RFC 4443, March 2006. Label Switched Paths (LSPs)", RFC 5884, June 2010.
[IntHost] Braden, R., "Requirements for Internet Hosts -- [BFD-Multi] Katz, D., Ward, D., "Bidirectional Forwarding Detection
Communication Layers", RFC 1122, October 1989. (BFD) for Multihop Paths", RFC 5883, June 2010.
[NetTerms] Jacobsen, O., Lynch, D., "A Glossary of Networking [BFD-VCCV] Nadeau, T., Pignataro, C., "Bidirectional Forwarding
Terms", RFC 1208, March 1991. Detection (BFD) for the Pseudowire Virtual Circuit
Connectivity Verification (VCCV)", RFC 5885, June
2010.
[MPLS-P2MP] Yasukawa, S., Farrel, A., King, D., Nadeau, T., [Comp] Bonaventure, O., "Computer Networking: Principles,
"Operations and Management (OAM) Requirements for Protocols and Practice", 2008.
Point-to-Multipoint MPLS Networks", RFC 4687,
September 2006. [Cont] Dugal, D., Pignataro, C., Dunn, R., "Protecting the
Router Control Plane", RFC 6192, March 2011.
[Dup] Uijterwaal, H., "A One-Way Packet Duplication Metric",
RFC 5560, May 2009.
[G-ACh] Bocci, M., Vigoureux, M., Bryant, S., "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., Pignataro, C., "ICMP
Extensions for Multiprotocol Label Switching", RFC Extensions for Multiprotocol Label Switching", RFC
4950, August 2007. 4950, August 2007.
[ICMP-Int] Atlas, A., Bonica, R., Pignataro, C., Shen, N., Rivers,
JR., "Extending ICMP for Interface 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., Pignataro, C.,
"Extended ICMP to Support Multi-Part Messages", RFC "Extended ICMP to Support Multi-Part Messages", RFC
4884, April 2007. 4884, April 2007.
[ICMP-Int] Atlas, A., Bonica, R., Pignataro, C., Shen, N., Rivers, [ICMPv4] Postel, J., "Internet Control Message Protocol", STD 5,
JR., "Extending ICMP for Interface and Next-Hop RFC 792, September 1981.
Identification", RFC 5837, April 2010.
[TCPIP-Tools] Kessler, G., Shepard, S., "A Primer On Internet and [ICMPv6] Conta, A., Deering, S., and M. Gupta, "Internet Control
TCP/IP Tools and Utilities", RFC 2151, June 1997. Message Protocol (ICMPv6) for the Internet Protocol
Version 6 (IPv6) Specification", RFC 4443, March 2006.
[NetTools] Enger, R., Reynolds, J., "FYI on a Network Management [IEEE802.1Q] IEEE 802.1Q, "IEEE Standard for Local and metropolitan
Tool Catalog: Tools for Monitoring and Debugging area networks - Media Access Control (MAC) Bridges and
TCP/IP Internets and Interconnected Devices", RFC Virtual Bridged Local Area Networks", October 2012.
1470, June 1993.
[IPPM-FW] Paxson, V., Almes, G., Mahdavi, J., and Mathis, M., [IEEE802.3ah] IEEE 802.3, "IEEE Standard for Information technology -
"Framework for IP Performance Metrics", RFC 2330, May Local and metropolitan area networks - Carrier sense
1998. multiple access with collision detection (CSMA/CD)
access method and physical layer specifications",
clause 57, December 2008.
[IPPM-Con] Mahdavi, J., Paxson, V., "IPPM Metrics for Measuring [IntHost] Braden, R., "Requirements for Internet Hosts --
Connectivity", RFC 2678, September 1999. Communication Layers", RFC 1122, October 1989.
[IPPM-1DM] Almes, G., Kalidindi, S., Zekauskas, M., "A One-way [IPPM-1DM] Almes, G., Kalidindi, S., Zekauskas, M., "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., Zekauskas, M., "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., Zekauskas, M., "A Round-trip
Delay Metric for IPPM", RFC 2681, September 1999. Delay Metric for IPPM", RFC 2681, September 1999.
[PM-CONS] Clark, A. and B. Claise, "Guidelines for Considering [IPPM-Con] Mahdavi, J., Paxson, V., "IPPM Metrics for Measuring
New Performance Metric Development", BCP 170, RFC Connectivity", RFC 2678, September 1999.
6390, October 2011.
[OWAMP] Shalunov, S., Teitelbaum, B., Karp, A., Boote, J., and [IPPM-FW] Paxson, V., Almes, G., Mahdavi, J., and Mathis, M.,
Zekauskas, M., "A One-way Active Measurement Protocol "Framework for IP Performance Metrics", RFC 2330, May
(OWAMP)", RFC 4656, September 2006. 1998.
[TWAMP] Hedayat, K., Krzanowski, R., Morton, A., Yum, K., and [ITU-G8113.1] ITU-T Recommendation G.8113.1/Y.1372.1, "Operations,
Babiarz, J., "A Two-Way Active Measurement Protocol Administration and Maintenance mechanism for MPLS-TP
(TWAMP)", RFC 5357, October 2008. in Packet Transport Network (PTN)", November 2012.
[Reorder] Morton, A., Ciavattone, L., Ramachandran, G., Shalunov, [ITU-G8113.2] ITU-T Recommendation G.8113.2/Y.1372.2, "Operations,
S., and J. Perser, "Packet Reordering Metrics", RFC administration and maintenance mechanisms for MPLS-TP
4737, November 2006. networks using the tools defined for MPLS", November
2012.
[Dup] Uijterwaal, H., "A One-Way Packet Duplication Metric", [ITU-T-CT] Betts, M., "Allocation of a Generic Associated Channel
RFC 5560, May 2009. Type for ITU-T MPLS Transport Profile Operation,
Maintenance, and Administration (MPLS-TP OAM)", RFC
6671, November 2012.
[BFD] Katz, D., Ward, D., "Bidirectional Forwarding Detection [ITU-T-G.806] ITU-T Recommendation G.806, "Characteristics of
(BFD)", RFC 5880, June 2010. transport equipment - Description methodology and
generic functionality", January 2009.
[BFD-IP] Katz, D., Ward, D., "Bidirectional Forwarding Detection [ITU-T-Y1711] ITU-T Recommendation Y.1711, "Operation & Maintenance
(BFD) for IPv4 and IPv6 (Single Hop)", RFC 5881, June mechanism for MPLS networks", February 2004.
2010.
[BFD-Gen] Katz, D., Ward, D., "Generic Application of [ITU-T-Y1731] ITU-T Recommendation G.8013/Y.1731, "OAM Functions and
Bidirectional Forwarding Detection (BFD)", RFC 5882, Mechanisms for Ethernet-based Networks", July 2011.
June 2010.
[BFD-Multi] Katz, D., Ward, D., "Bidirectional Forwarding Detection [ITU-Terms] ITU-R/ITU-T Terms and Definitions, online, 2013.
(BFD) for Multihop Paths", RFC 5883, June 2010.
[BFD-LSP] Aggarwal, R., Kompella, K., Nadeau, T., and Swallow, [L2TP-EC] McGill, N. and C. Pignataro, "Layer 2 Tunneling
G., "Bidirectional Forwarding Detection (BFD) for MPLS Protocol Version 3 (L2TPv3) Extended Circuit Status
Label Switched Paths (LSPs)", RFC 5884, June 2010. Values", RFC 5641, August 2009.
[BFD-VCCV] Nadeau, T., Pignataro, C., "Bidirectional Forwarding [Lock-Loop] Boutros, S., Sivabalan, S., Aggarwal, R., Vigoureux,
Detection (BFD) for the Pseudowire Virtual Circuit M., Dai, X., "MPLS Transport Profile Lock Instruct and
Connectivity Verification (VCCV)", RFC 5885, June Loopback Functions", RFC 6435, November 2011.
2010.
[TP-OAM-FW] Busi, I., Allan, D., "Operations, Administration and [LSP-Ping] Kompella, K., Swallow, G., "Detecting Multi-Protocol
Maintenance Framework for MPLS-based Transport Label Switched (MPLS) Data Plane Failures", RFC 4379,
Networks ", RFC 6371, September 2011. February 2006.
[TP-CC-CV] Allan, D., Swallow, G., Drake, J., "Proactive [Mng] Farrel, A., "Inclusion of Manageability Sections in
Connectivity Verification, Continuity Check and Remote Path Computation Element (PCE) Working Group Drafts",
Defect indication for MPLS Transport Profile", RFC RFC 6123, February 2011.
6428, November 2011.
[MPLS-LM-DM] Frost, D., Bryant, S., "Packet Loss and Delay
Measurement for MPLS Networks", RFC 6374, September
2011.
[MPLS-OAM] Nadeau, T., Morrow, M., Swallow, G., Allan, D.,
Matsushima, S., "Operations and Management (OAM)
Requirements for Multi-Protocol Label Switched (MPLS)
Networks", RFC 4377, February 2006.
[MPLS-OAM-FW] Allan, D., Nadeau, T., "A Framework for Multi-Protocol
Label Switching (MPLS) Operations and Management
(OAM)", RFC 4378, February 2006.
[MPLS-P2MP] Yasukawa, S., Farrel, A., King, D., Nadeau, T.,
"Operations and Management (OAM) Requirements for
Point-to-Multipoint MPLS Networks", RFC 4687,
September 2006.
[MPLS-TP-OAM] Vigoureux, M., Ward, D., Betts, M., "Requirements for
OAM in MPLS Transport Networks", RFC 5860, May 2010.
[NetTerms] Jacobsen, O., Lynch, D., "A Glossary of Networking
Terms", RFC 1208, March 1991.
[NetTools] Enger, R., Reynolds, J., "FYI on a Network Management
Tool Catalog: Tools for Monitoring and Debugging
TCP/IP Internets and Interconnected Devices", RFC
1470, June 1993.
[OAM-Analys] Sprecher, N., Fang, L., "An Overview of the OAM Tool
Set for MPLS based Transport Networks", RFC 6669,
July 2012.
[OAM-Def] Andersson, L., Van Helvoort, H., Bonica, R., Romascanu,
D., Mansfield, S., "Guidelines for the use of the OAM
acronym in the IETF ", RFC 6291, June 2011.
[OAM-Label] Ohta, H., "Assignment of the 'OAM Alert Label' for
Multiprotocol Label Switching Architecture (MPLS)
Operation and Maintenance (OAM) Functions", RFC 3429,
November 2002.
[OnDemand-CV] Gray, E., Bahadur, N., Boutros, S., Aggarwal, R. "MPLS [OnDemand-CV] Gray, E., Bahadur, N., Boutros, S., Aggarwal, R. "MPLS
On-Demand Connectivity Verification and Route On-Demand Connectivity Verification and Route
Tracing", RFC 6426, November 2011. Tracing", RFC 6426, November 2011.
[MPLS-LM-DM] Frost, D., Bryant, S., "Packet Loss and Delay [OWAMP] Shalunov, S., Teitelbaum, B., Karp, A., Boote, J., and
Measurement for MPLS Networks", RFC 6374, September Zekauskas, M., "A One-way Active Measurement Protocol
2011. (OWAMP)", RFC 4656, September 2006.
[TP-LM-DM] Frost, D., Bryant, S., "A Packet Loss and Delay [PARIS] Brice Augustin, Timur Friedman and Renata Teixeira,
Measurement Profile for MPLS-Based Transport "Measuring Load-balanced Paths in the Internet", IMC,
Networks", RFC 6375, September 2011. 2007.
[TP-Fault] Swallow, G., Fulignoli, A., Vigoureux, M., Boutros, S., [PM-CONS] Clark, A. and B. Claise, "Guidelines for Considering
"MPLS Fault Management Operations, Administration, and New Performance Metric Development", BCP 170, RFC
Maintenance (OAM)", RFC 6427, November 2011. 6390, October 2011.
[Lock-Loop] Boutros, S., Sivabalan, S., Aggarwal, R., Vigoureux, [PW-ACH] Bryant, S., Swallow, G., Martini, L., McPherson, D.,
M., Dai, X., "MPLS Transport Profile Lock Instruct and "Pseudowire Emulation Edge-to-Edge (PWE3) Control Word
Loopback Functions", RFC 6435, November 2011. for Use over an MPLS PSN", RFC 4385, February 2006.
[ITU-T-CT] Betts, M., "Allocation of a Generic Associated Channel [PW-G-ACh] Li, H., Martini, L., He, J., Huang, F., "Using the
Type for ITU-T MPLS Transport Profile Operation, Generic Associated Channel Label for Pseudowire in the
Maintenance, and Administration (MPLS-TP OAM)", RFC MPLS Transport Profile (MPLS-TP)", RFC 6423, November
6671, November 2012. 2011.
[PW-MAP] Aissaoui, M., Busschbach, P., Martini, L., Morrow, M.,
Nadeau, T., and Y(J). Stein, "Pseudowire (PW)
Operations, Administration, and Maintenance (OAM)
Message Mapping", RFC 6310, July 2011.
[PW-Map] M. Aissaoui, P. Busschbach, L. Martini, M. Morrow, T. [PW-Map] M. Aissaoui, P. Busschbach, L. Martini, M. Morrow, T.
Nadeau, "Pseudowire (PW) Operations, Administration, Nadeau, "Pseudowire (PW) Operations, Administration,
and Maintenance (OAM) Message Mapping", RFC 6310, July and Maintenance (OAM) Message Mapping", RFC 6310, July
2011. 2011.
[PW-G-ACh] Li, H., Martini, L., He, J., Huang, F., "Using the [Reorder] Morton, A., Ciavattone, L., Ramachandran, G., Shalunov,
Generic Associated Channel Label for Pseudowire in the S., and J. Perser, "Packet Reordering Metrics", RFC
MPLS Transport Profile (MPLS-TP)", RFC 6423, November 4737, November 2006.
2011.
[OAM-Def] Andersson, L., Van Helvoort, H., Bonica, R., Romascanu, [Signal] Yasukawa, S., "Signaling Requirements for Point-to-
D., Mansfield, S., "Guidelines for the use of the OAM Multipoint Traffic-Engineered MPLS Label Switched
acronym in the IETF ", RFC 6291, June 2011. Paths (LSPs)", RFC 4461, April 2006.
[OAM-Analys] Sprecher, N., Fang, L., "An Overview of the OAM Tool [TCPIP-Tools] Kessler, G., Shepard, S., "A Primer On Internet and
Set for MPLS based Transport Networks", RFC 6669, TCP/IP Tools and Utilities", RFC 2151, June 1997.
July 2012.
[TP-CC-CV] Allan, D., Swallow, G., Drake, J., "Proactive
Connectivity Verification, Continuity Check and Remote
Defect indication for MPLS Transport Profile", RFC
6428, November 2011.
[TP-Fault] Swallow, G., Fulignoli, A., Vigoureux, M., Boutros, S.,
"MPLS Fault Management Operations, Administration, and
Maintenance (OAM)", RFC 6427, November 2011.
[TP-LM-DM] Frost, D., Bryant, S., "A Packet Loss and Delay
Measurement Profile for MPLS-Based Transport
Networks", RFC 6375, September 2011.
[TP-OAM-FW] Busi, I., Allan, D., "Operations, Administration and
Maintenance Framework for MPLS-based Transport
Networks ", RFC 6371, September 2011.
[TP-Term] Van Helvoort, H., Andersson, L., Sprecher, N., "A [TP-Term] Van Helvoort, H., Andersson, L., Sprecher, N., "A
Thesaurus for the Terminology used in Multiprotocol Thesaurus for the Terminology used in Multiprotocol
Label Switching Transport Profile (MPLS-TP) Label Switching Transport Profile (MPLS-TP)
drafts/RFCs and ITU-T's Transport Network drafts/RFCs and ITU-T's Transport Network
Recommendations", work-in-progress, draft-ietf-mpls- Recommendations", work-in-progress, draft-ietf-mpls-
tp-rosetta-stone, July 2012. tp-rosetta-stone, July 2012.
[Cont] Dugal, D., Pignataro, C., Dunn, R., "Protecting the
Router Control Plane", RFC 6192, March 2011.
[Mng] Farrel, A., "Inclusion of Manageability Sections in
Path Computation Element (PCE) Working Group Drafts",
RFC 6123, February 2011.
[TRILL-OAM] Senevirathne, T., Bond, D., Aldrin, S., Li, Y., Watve, [TRILL-OAM] Senevirathne, T., Bond, D., Aldrin, S., Li, Y., Watve,
R., "Requirements for Operations, Administration, and R., "Requirements for Operations, Administration, and
Maintenance (OAM) in Transparent Interconnection of Maintenance (OAM) in Transparent Interconnection of
Lots of Links (TRILL)", RFC 6905, March 2013. Lots of Links (TRILL)", RFC 6905, March 2013.
[IEEE802.1Q] IEEE 802.1Q, "IEEE Standard for Local and metropolitan [TWAMP] Hedayat, K., Krzanowski, R., Morton, A., Yum, K., and
area networks - Media Access Control (MAC) Bridges and Babiarz, J., "A Two-Way Active Measurement Protocol
Virtual Bridged Local Area Networks", October 2012. (TWAMP)", RFC 5357, October 2008.
[ITU-T-Y1731] ITU-T Recommendation G.8013/Y.1731, "OAM Functions and
Mechanisms for Ethernet-based Networks", July 2011.
[ITU-T-Y1711] ITU-T Recommendation Y.1711, "Operation & Maintenance
mechanism for MPLS networks", February 2004.
[IEEE802.3ah] IEEE 802.3, "IEEE Standard for Information technology -
Local and metropolitan area networks - Carrier sense
multiple access with collision detection (CSMA/CD)
access method and physical layer specifications",
clause 57, December 2008.
[ITU-T-G.806] ITU-T Recommendation G.806, "Characteristics of
transport equipment - Description methodology and
generic functionality", January 2009.
[ITU-G8113.2] ITU-T Recommendation G.8113.2/Y.1372.2, "Operations, [VCCV] Nadeau, T., Pignataro, C., "Pseudowire Virtual Circuit
administration and maintenance mechanisms for MPLS-TP Connectivity Verification (VCCV): A Control Channel
networks using the tools defined for MPLS", November for Pseudowires", RFC 5085, December 2007.
2012.
[ITU-G8113.1] ITU-T Recommendation G.8113.1/Y.1372.1, "Operations, [VCCV-SURVEY] Del Regno, N., Malis, A., "The Pseudowire (PW) &
Administration and Maintenance mechanism for MPLS-TP Virtual Circuit Connectivity Verification (VCCV)
in Packet Transport Network (PTN)", November 2012. Implementation Survey Results", work-in-progress,
draft-ietf-pwe3-vccv-impl-survey-results, August 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 published 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 memos that define the requirements or the framework of also includes RFCs that define the requirements or the framework of
OAM in the context of a specific transport technology, or describe OAM in a specific context (e.g., MPLS-TP).
how to use existing OAM tools in a new transport technology.
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.
+-----------+--------------------------------------+----------+ +-----------+--------------------------------------+----------+
| Category | Title | RFC | | Category | Title | RFC |
+-----------+--------------------------------------+----------+ +-----------+--------------------------------------+----------+
|IP Ping | Requirements for Internet Hosts -- | RFC 1122 | |IP Ping | Requirements for Internet Hosts -- | RFC 1122 |
| | Communication Layers [IntHost] | | | | Communication Layers [IntHost] | |
| +--------------------------------------+----------+ | +--------------------------------------+----------+
skipping to change at page 41, line 7 skipping to change at page 44, line 27
+-----------+--------------------------------------+----------+ +-----------+--------------------------------------+----------+
|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 Table 5 Summary of IETF OAM Related RFCs
A.2. List of Selected Non-IETF OAM Documents A.2. List of Selected Non-IETF OAM Documents
In addition to the OAM mechanisms defined by the IETF, the IEEE and In addition to the OAM tools defined by the IETF, the IEEE and ITU-T
ITU-T have also defined various OAM mechanisms that focus on have also defined various OAM tools that focus on Ethernet, and
Ethernet, and various other transport network environments. These various other transport network environments. These various tools,
various mechanisms, defined by the three standard organizations, are defined by the three standard organizations, are often tightly
often tightly coupled, and have had a mutual effect on each other. coupled, and have had a mutual effect on each other. The ITU-T and
The ITU-T and IETF have both defined OAM mechanisms for MPLS LSPs, IETF have both defined OAM tools for MPLS LSPs, [ITU-T-Y1711] and
[ITU-T-Y1711] and [LSP-Ping]. The following OAM standards by the IEEE [LSP-Ping]. The following OAM standards by the IEEE and ITU-T are to
and ITU-T are to some extent linked to IETF OAM mechanisms listed some extent linked to IETF OAM tools listed above and are mentioned
above and are mentioned here only as reference material: here only as reference material:
o OAM mechanisms 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
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 in
some cases operators use a multi-layered OAM approach, which is a some cases operators use a multi-layered OAM approach, which is a
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