--- 1/draft-ietf-opsawg-oam-overview-01.txt 2010-10-07 15:12:05.000000000 +0200 +++ 2/draft-ietf-opsawg-oam-overview-02.txt 2010-10-07 15:12:05.000000000 +0200 @@ -1,18 +1,23 @@ Operations and Management Area Working Group T. Mizrahi Internet Draft Marvell -Intended status: Informational July 12, 2010 -Expires: January 2011 +Intended status: Informational N. Sprecher +Expires: April 2011 Nokia Siemens Networks + E. Bellagamba + Ericsson + Y. Weingarten + Nokia Siemens Networks + October 7, 2010 An Overview of Operations, Administration, and Maintenance (OAM) Mechanisms - draft-ietf-opsawg-oam-overview-01.txt + draft-ietf-opsawg-oam-overview-02.txt Status of this Memo This Internet-Draft is submitted to IETF in full conformance with the provisions of BCP 78 and BCP 79. Internet-Drafts are working documents of the Internet Engineering Task Force (IETF), its areas, and its working groups. Note that other groups may also distribute working documents as Internet- Drafts. @@ -21,133 +26,138 @@ and may be updated, replaced, or obsoleted by other documents at any time. It is inappropriate to use Internet-Drafts as reference material or to cite them other than as "work in progress." The list of current Internet-Drafts can be accessed at http://www.ietf.org/ietf/1id-abstracts.txt. The list of Internet-Draft Shadow Directories can be accessed at http://www.ietf.org/shadow.html. - This Internet-Draft will expire on January 12, 2011. + This Internet-Draft will expire on April 7, 2011. Copyright Notice Copyright (c) 2010 IETF Trust and the persons identified as the document authors. All rights reserved. This document is subject to BCP 78 and the IETF Trust's Legal Provisions Relating to IETF Documents (http://trustee.ietf.org/license-info) in effect on the date of publication of this document. Please review these documents carefully, as they describe your rights and restrictions with respect to this document. Code Components extracted from this document must include Simplified BSD License text as described in Section 4.e of the Trust Legal Provisions and are provided without warranty as described in the Simplified BSD License. Abstract Operations, Administration, and Maintenance (OAM) is a general term - that refers to detecting and reporting link failures. OAM mechanisms - have been defined for various layers in the protocol stack, and are - used with a variety of protocols. + that refers to a toolset that can be used for detecting and reporting + connection failures or measurement of connection performance + parameters. OAM mechanisms have been defined for various layers in + the protocol stack, and are used with a variety of protocols. This document presents an overview of the OAM mechanisms that have been defined and are currently being defined by the IETF, as well as a comparison to other OAM mechanisms that have been defined by the IEEE and ITU-T. Table of Contents 1. Introduction................................................4 2. Conventions used in this document............................8 3. Basic Terminology...........................................8 3.1. Abbreviations..........................................8 3.2. Terminology used in OAM Standards.......................9 3.2.1. General Terms......................................9 - 3.2.2. OAM Maintenance Entities...........................9 + 3.2.2. OAM Maintenance Entities and Communication Links...10 3.2.3. OAM Maintenance Points............................10 - 3.2.4. OAM Link Failures.................................10 - 3.2.5. Summary of OAM Terms used in the Standards.........10 - 4. OAM Functions..............................................12 - 4.1. ICMP Ping.............................................12 - 4.2. Bidirectional Forwarding Detection (BFD)...............12 - 4.2.1. Overview.........................................12 - 4.2.2. BFD Control.......................................12 - 4.2.3. BFD Echo.........................................13 - 4.3. LSP Ping..............................................13 - 4.4. PWE3 Virtual Circuit Connectivity Verification (VCCV)...13 - 4.5. IP Performance Metrics (IPPM)..........................14 - 4.5.1. Overview.........................................14 - 4.5.2. OWAMP/TWAMP Control...............................14 - 4.5.3. OWAMP/TWAMP Test..................................14 - 4.6. ITU-T Y.1711..........................................14 - 4.6.1. Overview.........................................14 - 4.6.2. Connectivity Verification (CV)....................15 - 4.6.3. Fast Failure Detection (FFD)......................15 - 4.6.4. Forward Defect Indication (FDI)...................15 - 4.6.5. Backward Defect Indication (BDI)..................15 - - 4.7. ITU-T Y.1731..........................................16 - 4.7.1. Overview.........................................16 - 4.7.2. ETH-CC...........................................16 - 4.7.3. ETH-LB...........................................17 - 4.7.4. ETH-TST..........................................17 - 4.7.5. ETH-LT...........................................17 - 4.7.6. ETH-AIS..........................................17 - 4.7.7. ETH-LCK..........................................17 - 4.7.8. ETH-RDI..........................................18 - 4.7.9. ETH-APS..........................................18 - 4.7.10. ETH-LM..........................................18 - 4.7.11. ETH-DM..........................................18 - 4.8. IEEE 802.1ag..........................................19 - 4.8.1. Overview.........................................19 - 4.8.2. Continuity Check..................................19 - 4.8.3. Loopback.........................................19 - 4.8.4. Linktrace........................................20 - 4.9. IEEE 802.3ah..........................................20 - 4.9.1. Overview.........................................20 - 4.9.2. Remote Failure Indication.........................20 - 4.9.3. Remote Loopback...................................20 - 4.9.4. Link Monitoring...................................20 - 4.10. MPLS-TP OAM..........................................20 - 4.10.1. Overview........................................20 - 4.10.2. Continuity Checks................................21 - 4.10.3. Connectivity Verification........................21 - 4.10.4. Diagnostic Tests.................................21 - 4.10.5. Route Tracing....................................22 - 4.10.6. Lock Instruct....................................22 - 4.10.7. Lock Reporting...................................22 - 4.10.8. Alarm Reporting..................................22 - 4.10.9. Remote Defect Indication.........................22 - 4.10.10. Client Failure Indication.......................22 - 4.10.11. Packet Loss Measurement.........................22 - 4.10.12. Packet Delay Measurement........................22 - 4.11. Summary of OAM Functions..............................22 - 4.12. Summary of Unidirectional Connectivity Check Mechanisms24 - 5. Security Considerations.....................................25 - 6. IANA Considerations........................................25 - 7. Acknowledgments............................................25 - 8. References.................................................25 - 8.1. Normative References...................................25 - 8.2. Informative References.................................28 + 3.2.4. Link Failures.....................................11 + 3.2.5. Connectivity Verification and Continuity Checks....11 + 3.2.6. Summary of OAM Terms used in the Standards.........11 + 4. OAM Functions..............................................13 + 4.1. ICMP Ping.............................................13 + 4.2. Bidirectional Forwarding Detection (BFD)...............13 + 4.2.1. Overview.........................................13 + 4.2.2. BFD Control.......................................13 + 4.2.3. BFD Echo.........................................14 + 4.3. LSP Ping..............................................14 + 4.4. PWE3 Virtual Circuit Connectivity Verification (VCCV)...15 + 4.5. IP Performance Metrics (IPPM)..........................15 + 4.5.1. Overview.........................................15 + 4.5.2. Control and Test Protocols........................16 + 4.5.3. OWAMP............................................16 + 4.5.4. TWAMP............................................17 + 4.6. ITU-T Y.1711..........................................17 + 4.6.1. Overview.........................................17 + 4.6.2. Connectivity Verification (CV)....................18 + 4.6.3. Fast Failure Detection (FFD)......................18 + 4.6.4. Forward Defect Indication (FDI)...................18 + 4.6.5. Backward Defect Indication (BDI)..................19 + 4.7. ITU-T Y.1731..........................................19 + 4.7.1. Overview.........................................19 + 4.7.2. ETH-CC...........................................19 + 4.7.3. ETH-LB...........................................20 + 4.7.4. ETH-TST..........................................20 + 4.7.5. ETH-LT...........................................20 + 4.7.6. ETH-AIS..........................................20 + 4.7.7. ETH-LCK..........................................20 + 4.7.8. ETH-RDI..........................................21 + 4.7.9. ETH-APS..........................................21 + 4.7.10. ETH-LM..........................................21 + 4.7.11. ETH-DM..........................................21 + 4.8. IEEE 802.1ag..........................................22 + 4.8.1. Overview.........................................22 + 4.8.2. Continuity Check..................................22 + 4.8.3. Loopback.........................................22 + 4.8.4. Linktrace........................................23 + 4.9. IEEE 802.3ah..........................................23 + 4.9.1. Overview.........................................23 + 4.9.2. Remote Failure Indication.........................23 + 4.9.3. Remote Loopback...................................23 + 4.9.4. Link Monitoring...................................23 + 4.10. MPLS-TP OAM..........................................23 + 4.10.1. Overview........................................23 + 4.10.2. Generic Associated Channel.......................24 + 4.10.3. MPLS-TP OAM Toolset..............................24 + 4.10.3.1. Continuity Check and Connectivity Verification25 + 4.10.3.2. Diagnostic Tests............................25 + 4.10.3.3. Route Tracing...............................25 + 4.10.3.4. Lock Instruct...............................25 + 4.10.3.5. Lock Reporting..............................26 + 4.10.3.6. Alarm Reporting.............................26 + 4.10.3.7. Remote Defect Indication....................26 + 4.10.3.8. Client Failure Indication...................26 + 4.10.3.9. Packet Loss Measurement.....................26 + 4.10.3.10. Packet Delay Measurement...................27 + 4.11. Summary of OAM Functions..............................27 + 4.12. Summary of Continuity Check Mechanisms................29 + 5. Security Considerations.....................................30 + 6. IANA Considerations........................................30 + 7. Acknowledgments............................................30 + 8. References.................................................30 + 8.1. Normative References...................................30 + 8.2. Informative References.................................32 1. Introduction - OAM is a general term that refers to detecting and reporting link - failures and defects. The term OAM has been used over the years in - several different contexts, as discussed in [OAM Soup]. In the - context of this document OAM refers to Operations, Administration, - and Maintenance, i.e., this document refers to OAM in the context of - monitoring communication links. Other aspects associated with the OAM - acronym, such as management, are not described in this document. + OAM is a general term that refers to a toolset that can be used for + detecting and reporting connection failures or measurement of + connection performance parameters. The term OAM has been used over + the years in several different contexts, as discussed in [OAM Soup]. + In the context of this document OAM refers to Operations, + Administration, and Maintenance, i.e., this document refers to OAM in + the context of monitoring communication links. Other aspects + associated with the OAM acronym, such as management, are not + described in this document. OAM was originally used in the world of telephony, and has been adopted in packet based networks. OAM mechanisms are used in various layers in the protocol stack, and are applied to a variety of different protocols. The IETF has defined OAM for several protocols, and is currently working on defining several new OAM protocols. A summary of these protocols, old and new, is listed below: @@ -159,64 +169,65 @@ o Virtual Circuit Connectivity Check (VCCV) for Pseudowires, as defined in [VCCV]. o ICMP Echo request, also known as Ping, as defined in [ICMPv4], and [ICMPv6]. ICMP Ping is a very simple and basic mechanism in failure diagnosis, and is not traditionally associated with OAM, but it is presented in this document for the sake of completeness, since both LSP Ping and VCCV are to some extent based on ICMP Ping. - o Bidirectional Forwarding Detection (BFD) is a family of standards - that are currently being defined by the IETF. BFD is intended to - be a generic OAM mechanism that can be used with various - encapsulation types, and in various medium types. + o Bidirectional Forwarding Detection (BFD) is defined in [BFD] as a + framework for a lightweight generic OAM mechanism. The intention + is to define a base mechanism that can be used with various + encapsulation types, network environments, and in various medium + types. - o OAM for MPLS-TP is currently being defined in the MPLS working - group. + o The OAM requirements for MPLS Transport Profile (MPLS-TP) are + defined in [MPLS-TP OAM], and the toolset is described in [MPLS-TP + OAM FW]. The OAM toolset for MPLS-TP is currently being defined in + the MPLS working group. o IP Performance Metrics (IPPM) is a working group in the IETF that defined common metrics for performance measurement, as well as a protocol for measuring delay and packet loss in IP networks. - While performance measurement is not directly related to link - failures, it is often associated with OAM. Alternative protocols - for performance measurement are defined, for example, in MPLS-TP - OAM [MPLS-TP OAM], and in Ethernet OAM [ITU-T Y.1731]. + Alternative protocols for performance measurement are defined, for + example, in MPLS-TP OAM [MPLS-TP OAM], and in Ethernet OAM [ITU-T + Y.1731]. In addition to the OAM mechanisms defined by the IETF, the IEEE and ITU-T have also defined various OAM mechanisms. These various mechanisms defined by the three standard organizations are often - tightly coupled, and have had a mutual effect on each other. For - example, the emerging MPLS-TP OAM is in many ways based on [ITU-T - Y.1731]. The ITU-T and IETF have both defined OAM mechanisms for MPLS - LSPs, [ITU-T Y.1711] and [LSP Ping]. The following OAM standards by - the IEEE and ITU-T are to some extent linked to IETF OAM mechanisms - listed above, and are also discussed in this document: + tightly coupled, and have had a mutual effect on each other. The ITU- + T and IETF have both defined OAM mechanisms for MPLS LSPs, [ITU-T + Y.1711] and [LSP Ping]. The following OAM standards by the IEEE and + ITU-T are to some extent linked to IETF OAM mechanisms listed above, + and are also discussed in this document: o OAM mechanisms for Ethernet based networks have been defined by both the ITU-T in [ITU-T Y.1731], and by the IEEE in [IEEE 802.1ag]. The IEEE 802.3 standard defines OAM for one-hop Ethernet links [IEEE 802.3ah]. o The ITU-T has defined OAM for MPLS LSPs in [ITU-T Y.1711]. This document summarizes the OAM mechanisms defined in the standards - above. The focus is on OAM mechanisms defined by the IETF, compared - with the relevant OAM mechanisms defined by the ITU-T and IEEE. We - first present a comparison of the terminology used in various OAM - standards, and then summarize the OAM functions that each OAM - standard provides. + above. The focus is on OAM mechanisms defined by the IETF. These + mechanisms will be compared with the relevant OAM mechanisms defined + by the ITU-T and IEEE, where applicable. We first present a + comparison of the terminology used in various OAM standards, and then + summarize the OAM functions that each OAM standard provides. Table 1 summarizes the OAM standards discussed in this document. +-----------+--------------------------------------+---------------+ - | | Title |Standard | + | | Title |Standard/Draft | +-----------+--------------------------------------+---------------+ |ICMPv4 Ping| Internet Control Message Protocol | RFC 792 | | | | | +-----------+--------------------------------------+---------------+ |ICMPv6 Ping| Internet Control Message Protocol | RFC 4443 | | | (ICMPv6) for the Internet Protocol | | | | Version 6 (IPv6) Specification | | +-----------+--------------------------------------+---------------+ |BFD | Bidirectional Forwarding Detection | RFC 5880 | | +--------------------------------------+---------------+ @@ -244,20 +255,32 @@ | | Label Switching (MPLS) Operations | | | | and Management (OAM) | | | +--------------------------------------+---------------+ | | Detecting Multi-Protocol Label | RFC 4379 | | | Switched (MPLS) Data Plane Failures | | | +--------------------------------------+---------------+ | | Operations and Management (OAM) | RFC 4687 | | | Requirements for Point-to-Multipoint | | | | MPLS Networks | | +-----------+--------------------------------------+---------------+ + |MPLS-TP | Requirements for OAM in MPLS-TP | RFC 5860 | + |OAM +--------------------------------------+---------------+ + | | MPLS Generic Associated Channel | RFC 5586 | + | +--------------------------------------+---------------+ + | | MPLS-TP OAM Framework |[MPLS-TP OAM FW| + | | |] - work in | + | | |progress | + | +--------------------------------------+---------------+ + | | MPLS-TP OAM Analysis |[OAM Analysis] | + | | | - work in | + | | |progress | + +-----------+--------------------------------------+---------------+ |PW VCCV | Pseudowire Virtual Circuit | RFC 5085 | | | Connectivity Verification (VCCV): | | | | A Control Channel for Pseudowires | | +-----------+--------------------------------------+---------------+ |IPPM | Framework for IP Performance Metrics | RFC 2330 | | +--------------------------------------+---------------+ | | IPPM Metrics for Measuring | RFC 2678 | | | Connectivity | | | +--------------------------------------+---------------+ | | A One-way Delay Metric for IPPM | RFC 2679 | @@ -277,24 +300,20 @@ | +--------------------------------------+---------------+ | | Assignment of the 'OAM Alert Label' | RFC 3429 | | | for Multiprotocol Label Switching | | | | Architecture (MPLS) Operation and | | | | Maintenance (OAM) Functions | | +-----------+--------------------------------------+---------------+ |ITU-T | OAM Functions and Mechanisms for |[ITU-T Y.1731] | |Ethernet | Ethernet-based Networks | | |OAM | | | +-----------+--------------------------------------+---------------+ - |MPLS-TP | Requirements for OAM in MPLS | RFC 5860 | - |OAM +--------------------------------------+---------------+ - | | MPLS Generic Associated Channel | RFC 5586 | - +-----------+--------------------------------------+---------------+ |IEEE | Connectivity Fault Management |[IEEE 802.1ag] | |CFM | | | +-----------+--------------------------------------+---------------+ |IEEE | Media Access Control Parameters, |[IEEE 802.3ah] | |802.3 | Physical Layers, and Management | | |link level | Parameters for Subscriber Access | | |OAM | Networks | | +-----------+--------------------------------------+---------------+ Table 1 Summary of OAM Standards @@ -378,65 +397,100 @@ A wide variety of terms is used in various OAM standards. Each of the OAM standards listed in the reference section includes a section that defines the relevant terms. A thesaurus of terminology for MPLS-TP terms is presented in [MPLS-TP Term], and provides a good summary of some of the OAM related terminology. This section presents a comparison of the terms used in various OAM standards, without fully quoting the definition of each term. For a formal definition of each term, refer to the references at the end of this document. The comparison focuses on three basic terms, and is - summarized in section 3 ..2.5. + summarized in section 3 ..2.6. -3.2.2. OAM Maintenance Entities +3.2.2. OAM Maintenance Entities and Communication Links A Maintenance Entity (ME) can be either a point-to-point or a point- - to-multipoint relationship between two or more Maintenance Points. + to-multipoint relationship between two or more Maintenance Points + (MP). The connectivity between these Maintenance Points is managed + and monitored by the OAM protocol. - The connectivity between these Maintenance Points is mangaged and - monitored by the OAM protocol. + A pair of MPs engaged in an ME are connected by a communication Link. + Link in this context may refer to a physical connection, or to a + logical path such as an MPLS LSP. The term Link is used throughout + this document to refer to the connection between the MPs that is + monitored by an OAM protocol. The term Maintenance Entity (ME) is defined in ITU-T standards (e.g. [ITU-T Y.1731]). Various terms are used to refer to an ME. For example, in MPLS terminology, an ME is simply referred to as an LSP. BFD does not explicitly use a term that is equivalent to ME, but rather uses the term "session", referring to the relationship between two nodes using a BFD protocol. + MPLS-TP has defined the terms ME and Maintenance Entity Group (MEG) + in [MPLS-TP OAM FW], similar to the terms defined by ITU-T. + 3.2.3. OAM Maintenance Points - A Maintenance Point (MP) is a node that uses an OAM protocol. A - Maintenance End Point (MEP) is one of the end points of an ME. A - Maintenance Intermediate Point (MIP) is a point between two MEPs, - that is able to respond to OAM frames, but does not initiate them. + A Maintenance Point (MP) is a function that is defined at a node in + the network, and either initiates or reacts to OAM messages. A + Maintenance End Point (MEP) is one of the end points of an ME, and + can initiate OAM messages and respond to them. A Maintenance + Intermediate Point (MIP) is a point between two MEPs, that is able to + respond to OAM frames, but does not initiate them. The terms MEP and MIP are defined in ITU-T standards (e.g. [ITU-T Y.1731]). The term Maintenance Point is a general term for MEPs and MIPs, and is used in [IEEE 802.1ag]. -3.2.4. OAM Link Failures + MPLS-TP has defined the terms MEP and MIP and their functional + characteristics in [MPLS-TP OAM FW], similar to the terms defined by + ITU-T. + +3.2.4. Link Failures The terms Failure, Fault, and Defect are intermittently used in the standards. In some standards, such as [IEEE 802.1ag], there is no distinction between these terms, while in other standards each of these terms refers to a different type of malfunction. The ITU-T distinguishes between these terms in [ITU-T G.806]. The term Fault refers to an inability to perform a required action, e.g., an unsuccessful attempt to deliver a packet. The term Defect refers to an interruption in the normal operation, such as a consecutive period of time where no packets are delivered successfully. The term Failure refers to the termination of the required function. While a Defect typically refers to a limited period of time, a failure refers to a long period of time. -3.2.5. Summary of OAM Terms used in the Standards +3.2.5. Connectivity Verification and Continuity Checks + + Two distinct classes of failure management functions are used in OAM + protocols, connectivity verification and continuity checks. The + distinction between these terms is defined in [MPLS-TP OAM], and is + used similarly in this document. + + Continuity checks are used to verify the liveness of a link, and are + typically sent proactively, though they can be invoked on-demand as + well. + + A connectivity verification function allows an MP to check whether it + is connected to a peer MP or not. A connectivity verification (CV) + protocol typically uses a CV message, followed by a CV reply that is + sent back to the originator. A CV function can be applied proactively + or on-demand. + + Connectivity verification and continuity checks are considered + complementary mechanisms, and are often used in conjunction with each + other. + +3.2.6. Summary of OAM Terms used in the Standards Table 2 provides a comparison of the terminology used in different OAM standards. +-----------+-------------+-----------+----------------------------+ | |Maintenance |Maintenance|Link Failure Terminology | | |Point |Entity | | | |Terminology |Terminology| | +-----------+-------------+-----------+----------------------------+ |ICMPv4 Ping|-Host | | | @@ -460,38 +514,39 @@ | | | | a path with a measurement | | | | | value "false". | + --------- + ----------- + --------- + -------------------------- + |ITU-T | LSR | LSP |-Fault, Defect, Failure: as | |Y.1711 | | | defined in [ITU-T G.806] | + --------- + ----------- + --------- + -------------------------- + |ITU-T |-MEP | ME |-Fault, Defect, Failure: as | |Y.1731 |-MIP | | defined in [ITU-T G.806] | | | | | | + --------- + ----------- + --------- + -------------------------- + - |MPLS-TP |-End Point |-LSP |-Fault, Defect, Failure: as | - |OAM |-Intermediate|-PW | defined in [ITU-T G.806] | - | |Point |-Section | | + |MPLS-TP |-End Point, |-LSP |-Fault, Defect, Failure: as | + |OAM | MEP |-PW | defined in [ITU-T G.806] | + | |-Intermediate|-Section | | + | | Point, MIP | | | + --------- + ----------- + --------- + -------------------------- + |IEEE |-MEP | ME |-Failure | |802.1ag |-MIP | |-Fault | | |-MP | |-Defect | + --------- + ----------- + --------- + -------------------------- + |IEEE | DTE | Link |-Failure | |802.3ah | | |-Fault | +-----------+-------------+-----------+----------------------------+ Table 2 Summary of OAM Terms 4. OAM Functions 4.1. ICMP Ping - ICMP provides a bidirectional connectivity check for the Internet + ICMP provides a connectivity verification function for the Internet Protocol. The originator transmits an echo request packet, and the receiver replies with an echo reply. ICMP ping is defined in two variants, [ICMPv4] is used for IPv4, and [ICMPv6] is used for IPv6. 4.2. Bidirectional Forwarding Detection (BFD) 4.2.1. Overview While multiple OAM mechanisms have been defined for various protocols in the protocol stack, Bidirectional Forwarding Detection [BFD], @@ -500,127 +555,226 @@ various medium types. The IETF has defined variants of the protocol for IP ([BFD IP], [BFD Multi]), for MPLS LSPs [BFD LSP], and for PWE3 [BFD VCCV]. BFD for MPLS-TP is currently evolving in the MPLS working group (e.g. [MPLS-TP Ping BFD]). BFD includes two main OAM functions, using two types of BFD packets: BFD Control packets, and BFD Echo packets. 4.2.2. BFD Control - BFD supports a unidirectional connectivity check, using BFD control - packets. BFD control packets are be sent in one of two modes: + BFD supports a bidirectional continuity check, using BFD control + packets, that are exchanged within a BFD session. BFD sessions + operate in one of two modes: o Asynchronous mode: in this mode BFD control packets are sent periodically. When the receiver detects that no BFD control packet have been received during a predetermined period of time, a failure is detected. o Demand mode: in this mode, BFD control packets are sent on-demand. Upon need, a system initiates a series of BFD control packets to verify the link. BFD control packets are sent independently in each direction of the link. - The transmission interval of BFD packets that are sent periodically, - is a result of negotiation between the two systems. Each BFD Control - packet includes the desired transmission interval, and the desired - reception interval, allowing the two systems to agree on common - intervals. + Each of the end-points of the monitored path maintains its own + session identification, called a Discriminator, both of which are + included in the BFD Control Packets that are exchanged between the + end-points. At the time of session establishment, the Discriminators + are exchanged between the two-end points. In addition, the + transmission (and reception) rate is negotiated between the two end- + points, based on information included in the control packets. These + transmission rates may be renegotiated during the session. - If no BFD Control packets are received during a fixed period of time - called the Detection Time, the session is declared to be down. The - detection time is a function of the negotiated transmission time, and - a parameter called Detect Mult. Detect Mult determines the number of + During normal operation of the session, i.e. no failures are + detected, the BFD session is in the Up state. If no BFD Control + packets are received during a fixed period of time, called the + Detection Time, the session is declared to be Down. The detection + time is a function of the negotiated transmission time, and a + parameter called Detect Mult. Detect Mult determines the number of missing BFD Control packets that cause the session to be declared as - down. This parameter is included in the BFD Control packet. - - The BFD Control packet also includes two fields that specify the - transmitting and receiving systems, called My Discriminator and Your - Discriminator, respectively. + Down. This parameter is included in the BFD Control packet. 4.2.3. BFD Echo - The echo function is a bidirectional connectivity check. A BFD echo + The echo function is used for connectivity verification. A BFD echo packet is sent to a peer system, and is looped back to the originator. The echo function can be used proactively, or on-demand. 4.3. LSP Ping The IETF MPLS working group has defined OAM for MPLS LSPs. The requirements and framework of this effort was defined in [MPLS OAM FW] and [MPLS OAM], respectively. The corresponding OAM mechanism - that was defined in this context is LSP Ping [LSP Ping]. LSP ping is - used to detect data plain failures in MPLS LSPs. The transmitting LSR - sends an echo request to a remote LSR, and in turn receives an echo - reply. LSP ping is used in one of two modes: + defined, in this context, is LSP Ping [LSP Ping]. + + LSP Ping is based on ICMP Ping and just like its predecessor may be + used in one of two modes: o "Ping" mode: In this mode LSP ping is used for end-to-end connectivity verification between two LSRs. o "Traceroute" mode: This mode is used for hop-by-hop fault localization. + LSP Ping extends the basic ICMP Ping operation (of data-plane + connectivity and continuity check) with functionality to verify + data-plane vs. control-plane consistency for a Forwarding Equivalence + Class (FEC) and also Maximum Transmission Unit (MTU) problems. 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 + before the faulty link or node. + + It should be noted that LSP Ping does support unique identification + of the LSP within an addressing domain. The identification is checked + using the full FEC identification. LSP Ping is easily extensible to + include additional information needed to support new functionality, + by use of Type-Length-Value (TLV) constructs. + + LSP Ping supports both asynchronous, as well as, on-demand + activation. In addition, extensions for LSP Ping are being defined + for point-to-multipoint LSPs in [P2MP LSP Ping] and for MPLS Tunnels + in [MPLS LSP Ping]. + 4.4. PWE3 Virtual Circuit Connectivity Verification (VCCV) - VCCV, as defined in [VCCV], maintains the connectivity status of a - pseudowire. VCCV is supported for both MPLS PWs and L2TPv3 PWs. + VCCV, as defined in [VCCV], provides end-to-end fault detection + and diagnostics for PWs (regardless of the underlying tunneling + technology). The VCCV switching function provides a control channel + associated with each PW (based on the PW Associated Channel Header + (ACH) which is defined in [PW ACH]), and allows sending OAM packets + in-band with PW data (using CC Type 1: In-band VCCV). - VCCV supports two possible Connectivity Verification (CV) types, - i.e., two modes of operation: + VCCV currently supports the following OAM mechanisms: ICMP Ping, LSP + Ping, and BFD. ICMP and LSP Ping are IP encapsulated before being + sent over the PW ACH. BFD for VCCV supports two modes of + encapsulation - either IP/UDP encapsulated (with IP/UDP header) or + PW-ACH encapsulated (with no IP/UDP header) and provides support to + signal the AC status. The use of the VCCV control channel provides + the context, based on the MPLS-PW label, required to bind and + bootstrap the BFD session to a particular pseudo wire (FEC), + eliminating the need to exchange Discriminator values. - o ICMP Ping: In this mode the CV is performed using an ICMP ping - packet format, as defined in [ICMPv4] or [ICMPv6]. + VCCV consists of two components: (1) signaled component to + communicate VCCV capabilities as part of VC label, and (2) switching + component to cause the PW payload to be treated as a control packet. - o LSP Ping: In this mode the LSP Ping packet format, as defined in - [LSP Ping] is used for CV. + VCCV is not directly dependent upon the presence of a control plane. + The VCCV capability negotiation may be performed as part of the PW + signaling when LDP is used. In case of manual configuration of the + PW, it is the responsibility of the operator to set consistent + options at both ends. 4.5. IP Performance Metrics (IPPM) 4.5.1. Overview The IPPM working group [IPPM FW] in the IETF defines common criteria and metrics for measuring performance of IP traffic. Some of the key RFCs published by this working group have defined metrics for measuring connectivity [rfc2678], delay [RFC2679, RFC 2681], and packet loss [RFC2681]. The IPPM working group has defined not only metrics for performance measurement, but also protocols that define how the measurement is carried out. The One-way Active Measurement Protocol [OWAMP] and the Two-Way Active Measurement Protocol [TWAMP] define a method and protocol for measuring delay and packet loss in IP networks. + OWAMP [OWAMP] enables measurement of one-way characteristics of IP + networks, such as one-way packet loss and one-way delay. For its + proper operation OWAMP requires accurate time of day setting at its + end points. + + TWAMP [TWAMP] is a similar protocol that enables measurement of two- + way (round trip) characteristics. TWAMP does not require accurate + time of day, and, furthermore, allows the use of a simple session + reflector, making it an attractive alternative to OWAMP. + OWAMP and TWAMP use two separate protocols: a Control plane protocol, and a Test plane protocol. -4.5.2. OWAMP/TWAMP Control +4.5.2. Control and Test Protocols - Each of these standards defines a Control protocol. This protocol is - layered over TCP, and is used to initiate measurement sessions, and - to communicate their results. + OWAMP and TWAMP control protocols run over TCP, while the test + protocols run over UDP. The purpose of the control protocols is to + initiate, start, and stop test sessions, and for OWAMP to fetch + results. The test protocols introduce test packets (which contain + sequence numbers and timestamps) along the IP path under test + according to a schedule, and record statistics of packet arrival. + Multiple sessions may be simultaneously defined, each with a session + identifier, and defining the number of packets to be sent, the amount + of padding to be added (and thus the packet size), the start time, + and the send schedule (which can be either a constant time between + test packets or exponentially distributed pseudo-random). Statistics + recorded conform to the relevant IPPM RFCs. -4.5.3. OWAMP/TWAMP Test + OWAMP and TWAMP test traffic is designed with security in mind. Test + packets are hard to detect because they are simply UDP streams + between negotiated port numbers, with potentially nothing static in + the packets. OWAMP and TWAMP also include optional authentication + and encryption for both control and test packets. - The Test protocol is layered over UDP, and is used to measure delay - and packet loss between the session endpoints. The Test session is - initiated by a Request/Response negotiation, followed by a set of - active test packets that are used for the measurement. +4.5.3. OWAMP + + OWAMP defines the following logical roles: Session-Sender, Session- + Receiver, Server, Control-Client, and Fetch-Client. The Session- + Sender originates test traffic that is received by the Session- + Receiver. The Server configures and manages the session, as well as + returning the results. The Control-Client initiates requests for + test sessions, triggers their start, and may trigger their + termination. The Fetch-Client requests the results of a completed + session. Multiple roles may be combined in a single host - for + example, one host may play the roles of Control-Client, Fetch-Client, + and Session-Sender, and a second playing the roles of Server and + Session-Receiver. + + In a typical OWAMP session the Control-Client establishes a TCP + connection to port 861 of the Server, which responds with a server + greeting message indicating supported security/integrity modes. The + Control-Client responds with the chosen communications mode and the + Server accepts the modes. The Control-Client then requests and fully + describes a test session to which the Server responds with its + acceptance and supporting information. More than one test session + may be requested with additional messages. The Control-Client then + starts a test session and the Server acknowledges. The Session- + Sender then sends test packets with pseudorandom padding to the + Session-Receiver until the session is complete or until the Control- + client stops the session. Once finished, the Fetch-Client sends a + fetch request to the server, which responds with an acknowledgement + and immediately thereafter the result data. + +4.5.4. TWAMP + + TWAMP defines the following logical roles: session-sender, session- + reflector, server, and control-client. These are similar to the + OWAMP roles, except that the Session-Reflector does not collect any + packet information, and there is no need for a Fetch-Client. + + In a typical TWAMP session the Control-Client establishes a TCP + connection to port 862 of the Server, and mode is negotiated as in + OWAMP. The Control-Client then requests sessions and starts them. + The Session-Sender sends test packets with pseudorandom padding to + the Session-Reflector which returns them with insertion of + timestamps. 4.6. ITU-T Y.1711 4.6.1. Overview As mentioned above (4.3.), the IETF defined LSP Ping as an OAM mechanism for MPLS. The ITU-T has also defined an OAM protocol for - MPLS, defined in [ITU-T Y.1711]. The standard defines mechanisms for - connectivity verification and fast failure detection, as well as - mechanism for reporting defects that have been identified in an LSP. + MPLS, defined in recommendation [ITU-T Y.1711]. This recommendation + defines mechanisms for connectivity verification and fast failure + detection, as well as mechanism for reporting defects that have been + identified in an LSP. MPLS OAM packets per Y.1711 are detected by a reserved MPLS label value. The reserved value is 14, and is defined in [OAM Label] as the 'OAM Alert Label'. 4.6.2. Connectivity Verification (CV) The CV function is used to detect connectivity defects in an LSP. CV frames are sent proactively at a rate of 1 per second. Each frame contains the Trail-Termination Source Identifier (TTSI), indicating @@ -664,26 +818,24 @@ The BDI function is used to inform the LSR at an LSP trail termination source point about a defect condition in the forward direction of an LSP. The LSR at the LSP trail termination sink point transmits the BDI to the upstream LSR through the return path. BDI packets are sent at the same transmission rate as FDI. 4.7. ITU-T Y.1731 4.7.1. Overview - The [ITU-T Y.1731] is a protocol for Ethernet OAM. It is presented in - this document as a reference point, since the OAM mechanisms that are - currently being defined by the IETF for MPLS-TP are in many ways - based on this standard. The standard defines various OAM functions, - including unidirectional and bidirectional continuity check, and - functions for performance monitoring. + The [ITU-T Y.1731] defines a protocol for Ethernet OAM. It is + presented in this document as a reference point. Y.1731 defines + various OAM functions, including continuity and connectivity + verification, and functions for performance monitoring. 4.7.2. ETH-CC The Ethernet Continuity Check function is a proactive function that allows a MEP to detect loss of continuity with any of the other MEPs in the MEG. This function also allows detection of other defect conditions, such as unintended connectivity between two MEGs. The ETH-CC function is used for one of three possible applications: fault management, performance monitoring (see 4.6.10.), and protection switching. @@ -882,125 +1034,209 @@ Link monitoring provides an event notification function, allowing peer devices to communicate defect conditions and diagnostic information. 4.10. MPLS-TP OAM 4.10.1. Overview The MPLS working group is currently working on defining the OAM - requirements and mechanisms for MPLS-TP. The requirements of MPLS-TP - OAM are defined in [MPLS-TP OAM], and are described below. + toolset that fulfill the requirements for MPLS-TP OAM. The full set + of requirements for MPLS-TP OAM are defined in [MPLS-TP OAM], and + include both general requirements for the behavior of the OAM + mechanisms and a set of operations that should be supported by the + OAM toolset. The set of mechanisms required are further elaborated + in [MPLS-TP OAM FW], that describes the general architecture of the + OAM system as well as giving overviews of the functionality of the + OAM toolset. - MPLS-TP OAM traffic uses a Generic Associated Channel (G-ACh), - defined in [G-ACh]. This standard defines that MPLS-TP OAM traffic - uses: + Some of the basic requirements for the OAM toolset for MPLS-TP are: - o An Associated Channel Header (ACH), also known as a Control Word - in the PWE3 terminology, is a 4-byte header that is added to OAM + 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 + forwarding are available, then the MPLS-TP OAM toolset should rely + on the IP routing and forwarding capabilities. On the other hand, + in environments where IP functionality is not available, the OAM + tools must still be able to operate without dependence on IP + forwarding and routing. + + o OAM packets and the user traffic are required to be congruent + (i.e. OAM packets are transmitted in-band) and there is a need to + differentiate OAM packets from user-plane ones. Inherent in this + requirement is the principle that MPLS-TP OAM be independent of + any existing control-plane, although it should not preclude use of + the control-plane functionality. + +4.10.2. Generic Associated Channel + + In order to address the requirement for in-band transmission of MPLS- + TP OAM traffic, MPLS-TP uses a Generic Associated Channel (G-ACh), + defined in [G-ACh] for LSP-based OAM traffic. This mechanism is based + on the same concepts as the PWE3 ACH and VCCV mechanisms. However, + to address the needs of LSPs as differentiated from PW, the following + concepts were defined for [G-ACh]: + + o An Associated Channel Header (ACH), that uses a format similar to + the PW Control Word, is a 4-byte header that is added to OAM packets. o A Generic Associated Label (GAL). The GAL is a reserved MPLS label - value. The reserved value is 13, and identifies the packet as an - MPLS-TP OAM packet. A GAL indicates the existence of the ACH - immediately after it. + value. The reserved value is 13, and indicates the existence of + the ACH immediately after it. - The analysis in [OAM Analysis] discusses various OAM mechanism that - were considered in order to satisfy the requirements in [MPLS-TP - OAM]. The MPLS working group currently plans to use a mixture of OAM +4.10.3. MPLS-TP OAM Toolset + + 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 + mechanisms and their ability to fulfill the required functionality. + The conclusions of this analysis are documented in [OAM Analysis]. + The MPLS working group currently plans to use a mixture of OAM mechanisms that are based on various existing standards, and adapt them to the requirements of [MPLS-TP OAM]. Some of the main building blocks of this solution are based on: o Bidirectional Forwarding Detection ([BFD], [BFD LSP]) for - proactive connectivity verification. + proactive continuity check and connectivity verification. o LSP Ping as defined in [LSP Ping] for on-demand connectivity verification. - o Y.1731 per the [ITU-T Y.1731], mainly for performance measurement. + o New protocol packets, using G-ACH, to address different + functionality. - The requirements of MPLS-TP OAM are summarized below. + o Performance measurement protocols that are based on the + functionality that is described in [ITU-T Y.1731]. -4.10.2. Continuity Checks + The following sub-sections describe the OAM tools that will be + defined for MPLS-TP as described in [MPLS-TP OAM FW]. - The continuity check is a proactive function that allows an End Point - to determine whether or not it receives traffic from its peer End - Points. +4.10.3.1. Continuity Check and Connectivity Verification -4.10.3. Connectivity Verification + Continuity Check and Connectivity Verification (CC-V) are OAM + operations generally used in tandem, and compliment each other. These + functions are generally run proactively, but may also be used on- + demand, either due to bandwidth considerations or for diagnoses of a + specific condition. Proactively [MPLS-TP OAM] states that the + function should allow the MEPs to monitor the liveness and + connectivity of a transport path. In on-demand mode, this function + should support monitoring between the MEPs and, in addition, between + a MEP and MIP.[MPLS-TP OAM FW] highlights the need for the CC-V + messages to include unique identification of the MEG that is being + monitored and the MEP that originated the message. The function, both + proactively and in on-demand mode, need to be transmitted at regular + rates pre-configured by the operator. - The connectivity verification is a function that allows an End Point - to verify its connectivity to a peer node. The connectivity check is - performed by sending a connectivity verification PDU to the peer - node, and receiving a reply within an expected time frame. This - function can be performed proactively or on-demand. +4.10.3.2. Diagnostic Tests -4.10.4. Diagnostic Tests + Diagnostic testing is a protocol that allows a network to send + special test data on a transport path. For example, this could be + used as part of bandwidth utilization measurement. - This function allows an End Point to perform an on-demand test, e.g., - for bandwidth measurement. +4.10.3.3. Route Tracing -4.10.5. Route Tracing + [MPLS-TP OAM] defines that there is a need for functionality that + would allow a path end-point to identify the intermediate and end- + points of the path. This function would be used in on-demand mode. + Normally, this path will be used for bidirectional PW, LSP, and + sections, however, unidirectional paths may be supported only if a + return path exists. - This on-demand function is used for path discovery and for locating - link failures. +4.10.3.4. Lock Instruct -4.10.6. Lock Instruct + The Lock Instruct function is used to notify a transport path end- + point of an administrative need to disable the transport path. This + functionality will generally be used in conjunction with some + intrusive OAM function, e.g. Performance measurement, Diagnostic + testing, to minimize the side-effect on user data traffic. - The lock instruct function allows an End Point to instruct its peers - to enter an administrative status where all traffic is halted except - the test traffic and OAM PDUs. +4.10.3.5. Lock Reporting -4.10.7. Lock Reporting + Lock Reporting is a function used by an end-point of a path to report + to its far-end end-point that a lock condition has been affected on + the path. - This function allows an Intermediate Point to report to an End Point - about a lock condition. +4.10.3.6. Alarm Reporting -4.10.8. Alarm Reporting + Alarm Reporting is a function used by an intermediate point of a + path, that becomes aware of a fault on the path, to report to the + end-points of the path. [MPLS-TP OAM FW] states that this may occur + as a result of a defect condition discovered at a server sub-layer. + This generates an Alarm Indication Signal (AIS) that continues until + the fault is cleared. The consequent action of this function is + detailed in [MPLS-TP OAM FW]. - This function allows an Intermediate Point to report to an End Point - about a defect condition. +4.10.3.7. Remote Defect Indication -4.10.9. Remote Defect Indication + Remote Defect Indication (RDI) is used proactively by a path end- + point to report to its peer end-point that a defect is detected on a + bidirectional connection between them. [MPLS-TP OAM] points out that + this function may be applied to a unidirectional LSP only if there a + return path exists. [MPLS-TP OAM FW] points out that this function + is associated with the proactive CC-V function. - This is a proactive function that allows the sender to indicate that - it encountered a defect conditions. +4.10.3.8. Client Failure Indication -4.10.10. Client Failure Indication + Client Failure Indication (CFI) is defined in [MPLS-TP OAM] to allow + the propagation information from one edge of the network to the + other. The information concerns a defect to a client, in the case + that the client does not support alarm notification. - This function allows the MPLS-TP network to relay information about a - fault condition in a client network, allowing the failure indication - to propagate from end to end over the MPLS-TP network. +4.10.3.9. Packet Loss Measurement -4.10.11. Packet Loss Measurement + Packet Loss Measurement is a function used to verify the quality of + the service. This function indicates the ratio of packets that are + not delivered out of all packets that are transmitted by the path + source. - This function measures the packet loss ratio between two peer End - Points. It can be performed proactively or on-demand. + There are two possible ways of determining this measurement: -4.10.12. Packet Delay Measurement + o Using OAM packets, it is possible to compute the statistics based + on a series of OAM packets. This, however, has the disadvantage of + being artificial, and may not be representative since part of the + packet loss may be dependent upon packet sizes. - This function measures the frame delay between two peer End Points. - Two modes of operation are supported, one-way DM, and two-way DM. + o Sending delimiting messages for the start and end of a measurement + period during which the source and sink of the path count the + packets transmitted and received. After the end delimiter, the + ratio would be calculated by the path OAM entity. + +4.10.3.10. Packet Delay Measurement + + 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 + end-points of a path (PW, LSP, or Section). Where: + + o One-way packet delay is the time 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 that packet by the destination + node. + + o Two-way packet delay is the time 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 loop-backed packet by the + same source node, when the loopback is performed at the packet's + destination node. + + Similarly to the packet loss measurement this could be performed in + either of the two ways outlined above. 4.11. Summary of OAM Functions Table 3 summarizes the OAM functions that are supported in each of the standards that were analyzed in this section. +-----------+-------+--------+--------+-----------+-------+--------+ - | Standard |Unidire|Bidirect|Path |Defect |Perform|Other | - | |ctional|ional |Discover|Indications|ance |Function| - | |Connect|Connecti|y | |Monitor|s | - | |ivity |vity | | |ing | | - | |Check |Check | | | | | + | Standard |Continu|Connecti|Path |Defect |Perform|Other | + | |ity |vity |Discover|Indications|ance |Function| + | |Check |Verifica|y | |Monitor|s | + | | |tion | | |ing | | +-----------+-------+--------+--------+-----------+-------+--------+ |ICMP Ping | | Echo | | | | | + --------- + ----- + ------ + ------ + --------- + ----- + ------ + |BFD |BFD |BFD | | | | | | |Control|Echo | | | | | + --------- + ----- + ------ + ------ + --------- + ----- + ------ + |LSP Ping | |"Ping" |"Tracero| | | | | | |mode |ute" | | | | | | | |mode | | | | + --------- + ----- + ------ + ------ + --------- + ----- + ------ + @@ -1034,30 +1270,30 @@ |OAM | | |Tracing | Reporting |-DM | tic Tes| | | | | |-Client | | s | | | | | | Failure | |-Lock | | | | | | Indication| | | | | | | |-Remote | | | | | | | | Defect | | | | | | | | Indication| | | +-----------+-------+--------+--------+-----------+-------+--------+ Table 3 Summary of OAM Functions -4.12. Summary of Unidirectional Connectivity Check Mechanisms +4.12. Summary of Continuity Check Mechanisms A key element in some of the OAM standards that are analyzed in this - document is the unidirectional connectivity check. It is thus - interesting to present a more detailed comparison of the connectivity - check mechanisms defined in OAM standards. Table 4 can be viewed as - an extension of Table 3, but is presented separately for convenience. - The table compares the OAM standards that support a unidirectional - connectivity check. MPLS-TP is not included in the comparison, as the - continuity check mechanism in MPLS-TP has not yet been defined. + document is the continuity check. It is thus interesting to present a + more detailed comparison of the connectivity check mechanisms defined + in OAM standards. Table 4 can be viewed as an extension of Table 3, + but is presented separately for convenience. The table compares the + OAM standards that support a continuity check. MPLS-TP is not + included in the comparison, as the continuity check mechanism in + MPLS-TP has not yet been defined. The "Tx Interval" column in the table specifies the period between two consequent message transmissions, while the "Source Identifier" column specifies the name of the field in the OAM packet that is used as the identifier of the transmitter. The "Error Codes" column specifies the possible error codes when the unidirectional connectivity check detects a failure. +-----------+-------+--------+---+--------+------------------------+ | |Mechani|Tx |UC/|Source | Error | @@ -1202,44 +1438,76 @@ [ITU-T Y.1711]"Operation & Maintenance mechanism for MPLS networks", February 2004. [IEEE 802.3ah]"Media Access Control Parameters, Physical Layers, and Management Parameters for Subscriber Access Networks", clause 57, September 2004. 8.2. Informative References - [P2MP Ping] Saxena, S., Farrel, A. , Yasukawa, S., "Detecting Data - Plane Failures in Point-to-Multipoint Multiprotocol - Label Switching (MPLS) - Extensions to LSP Ping", - draft-ietf-mpls-p2mp-lsp-ping, March 2010. - [OAM Soup] Andersson, L., Van Helvoort, H., Bonica, R., Romascanu, D., Mansfield, S., "The OAM Acronym Soup", draft-ietf- opsawg-mpls-tp-oam-def, June 2010. - [ITU-T G.806] "Characteristics of transport equipment - Description - methodology and generic functionality", January 2009. + [OAM Analysis] Sprecher, N., Bellagamba, E., Weingarten, Y., "MPLS-TP + OAM Analysis", draft-ietf-mpls-tp-oam-analysis, July + 2010. + + [MPLS-TP OAM FW] Busi, I., Niven-Jenkins, B., Allan, D., "MPLS-TP OAM + Framework", work-in-progress, draft-ietf-mpls-tp-oam- + framework, July, 2010. [MPLS-TP Term]Van Helvoort, H., Andersson, L., Sprecher, N., "A Thesaurus for the Terminology used in Multiprotocol Label Switching Transport Profile (MPLS-TP) drafts/RFCs and ITU-T's Transport Network Recommendations", draft-ietf-mpls-tp-rosetta-stone, May 2010. [MPLS-TP Ping BFD] Bahadur, N., Aggarwal, R., Ward, D., Nadeau, T., Sprecher, N., Weingarten, Y., "LSP-Ping and BFD encapsulation over ACH", draft-ietf-mpls-tp-lsp-ping- bfd-procedures, March 2010. - [OAM Analysis] Sprecher, N., Bellagamba, E., Weingarten, Y., "MPLS-TP - OAM Analysis", draft-ietf-mpls-tp-oam-analysis, July - 2010. + [P2MP Ping] Saxena, S., Farrel, A. , Yasukawa, S., "Detecting Data + Plane Failures in Point-to-Multipoint Multiprotocol + Label Switching (MPLS) - Extensions to LSP Ping", + draft-ietf-mpls-p2mp-lsp-ping, March 2010. + + [ITU-T G.806] "Characteristics of transport equipment - Description + methodology and generic functionality", January 2009. Authors' Addresses Tal Mizrahi Marvell + 6 Hamada St. + Yokneam, 20692 + Israel Email: talmi@marvell.com + + Nurit Sprecher + Nokia Siemens Networks + 3 Hanagar St. Neve Ne'eman B + Hod Hasharon, 45241 + Israel + + Email: nurit.sprecher@nsn.com + + Elisa Bellagamba + Ericsson + 6 Farogatan St. + Stockholm, 164 40 + Sweden + Phone: +46 761440785 + Email: elisa.bellagamba@ericsson.com + + Yaacov Weingarten + Nokia Siemens Networks + 3 Hanagar St. Neve Ne'eman B + Hod Hasharon, 45241 + Israel + + Phone: +972-9-775 1827 + Email: yaacov.weingarten@nsn.com