Pseudo-Wire Edge-to-Edge(PWE3) Thomas D. Nadeau Internet Draft Monique Morrow Expiration Date: April 2005 Cisco Systems Peter Busschbach Lucent Technologies Mustapha Aissaoui Alcatel Editors October 2004 Pseudo Wire (PW) OAM Message Mapping draft-ietf-pwe3-oam-msg-map-01.txt Status of this Memo This document is an Internet-Draft and is subject to all provisions of section 3 of RFC 3667. By submitting this Internet-Draft, each author represents that any applicable patent or other IPR claims of which he or she is aware have been or will be disclosed, and any of which he or she become aware will be disclosed, in accordance with RFC 3668. This document may not be modified, and derivative works of it may not be created, except to publish it as an RFC and to translate it into languages other than English. 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. Internet-Drafts are draft documents valid for a maximum of six months 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. Abstract This document enumerates the OAM defect state mapping from pseudo wire emulated edge-to-edge services over MPLS and IP transport networks to their native attached services. Table of Contents Status of this Memo.............................................1 Abstract........................................................1 Table of Contents...............................................1 1 Conventions used in this document.............................3 Nadeau, et al. Expires April 2005 [Page 1] Internet Draft draft-ietf-pwe3-oam-msg-map-01.txt October 2004 2 Contributors..................................................3 3 Scope.........................................................3 4 Terminology...................................................3 5 Introduction..................................................4 6 Reference Model and Defect Locations..........................4 7 PW Status and Defects.........................................5 7.1 PW Defects.................................................5 7.1.1 Packet Loss...........................................6 7.2 Defect Detection...........................................6 7.2.1 Defect Detection Tools................................6 7.2.2 Defect Detection Mechanism Applicability..............7 7.3 PW Defect Entry and Exit Procedures........................8 7.3.1 PW Down...............................................8 7.3.2 PW Up.................................................9 7.4 Alarm Messages and Consequent Actions.....................10 7.5 The Use of PW Status......................................10 7.6 The Use of L2TP STOPCCN and CDN...........................11 7.7 The Use of BFD Diagnostic Codes...........................11 8 Frame Relay Encapsulation....................................12 8.1 Frame Relay Management....................................12 8.2 FR AC State...............................................13 8.3 Mapping of Defect States from a PW to a Frame Relay AC....13 8.3.1 Procedures in FR Port Mode...........................14 8.4 Frame Relay Network and Attachment Circuit Defects........14 9 ATM Encapsulation............................................15 9.1 ATM Management............................................15 9.2 ATM AC State..............................................16 9.3 Mapping ATM and PW Defect States..........................16 9.4 Mapping of Defect States from a PW to a ATM AC............17 9.4.1 Inband ATM OAM over PW...............................17 9.4.2 Out-of-Band ATM OAM over PW..........................17 9.4.3 Procedures in ATM Port Mode..........................19 9.5 ATM Network and Attachment Circuit Defects................19 9.5.1 Inband ATM OAM over PW...............................19 9.5.2 Out-of-Band ATM OAM over PW..........................19 9.5.3 Procedures in ATM Port Mode..........................20 10 SONET Encapsulation (CEP)...................................20 11 TDM Encapsulation...........................................20 12 Ethernet Encapsulation......................................21 12.1 Ethernet AC State........................................22 12.2 Mapping of Defect States from a PW to a Ethernet AC......22 12.3 Frame Relay Network and Attachment Circuit Defects.......22 13 Security Considerations.....................................22 14 Acknowledgments.............................................22 15 References..................................................22 16 Intellectual Property Disclaimer............................24 Nadeau, et al. Expires April 2005 [Page 2] Internet Draft draft-ietf-pwe3-oam-msg-map-01.txt October 2004 17 Full Copyright Statement....................................24 18 Authors' Addresses..........................................25 1 Conventions used in this document The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in RFC 2119. 2 Contributors Thomas D. Nadeau, tnadeau@cisco.com Monique Morrow, mmorrow@cisco.com Peter B. Busschbach, busschbach@lucent.com Mustapha Aissaoui, mustapha.aissaoui@alcatel.com Matthew Bocci, matthew.bocci@alcatel.co.uk David Watkinson, david.watkinson@alcatel.com Yuichi Ikejiri, y.ikejiri@ntt.com Kenji Kumaki, kekumaki@kddi.com Satoru Matsushima, satoru@ft.solteria.net David Allan, dallan@nortelnetworks.com 3 Scope This document specifies the mapping of defect states between a Pseudo Wire and Attachment Circuits (AC) of the end-to-end emulated service. This document covers the case of PW and ACs of the same type in accordance to the PWE3 architecture [PWEARCH]. This document covers both PWE over MPLS PSN and PWE over IP PSN. 4 Terminology AIS Alarm Indication Signal AOM Administration, Operation and Maintenance BDI Backward Defect Indication CC Continuity Check CE Customer Edge CPCS Common Part Convergence Sublayer DLC Data Link Connection FDI Forward Defect Indication FRBS Frame Relay Bearer Service Nadeau, et al. Expires April 2005 [Page 3] Internet Draft draft-ietf-pwe3-oam-msg-map-01.txt October 2004 IWF Interworking Function LB Loopback NE Network Element OAM Operations and Maintenance PE Provider Edge PW Pseudowire PSN Packet Switched Network RDI Remote Defect Indicator SDU Service Data Unit VCC Virtual Channel Connection VPC Virtual Path Connection The rest of this document will follow the following convention: The PW can ride over three types of Packet Switched Network (PSN). A PSN which makes use of LSPs as the tunneling technology to forward the PW packets will be referred to as an MPLS PSN. A PSN which makes use of MPLS-in-IP tunneling [MPLS-in-IP], with a MPLS shim header used as PW demultiplexer, will be referred to as an MPLS-IP PSN. A PSN which makes use of L2TPv3 [L2TPv3] as the tunneling technology will be referred to as L2TP-IP PSN. If LSP-Ping is run over a PW as described in [VCCV] it will be referred to as VCCV-Ping. If BFD is run over a PW as described in [VCCV] it will be referred to as VCCV-BFD. 5 Introduction This document describes how PW defects can be detected; how alarm information is exchanged between PEs; and how defects detected in pseudo-wires are mapped to OAM messages native to the emulated services and vice versa. The objective of this document is to standardize the behavior of PEs with respects to failures on PWs and ACs, so that there is no ambiguity about the alarms generated and consequent actions undertaken by PEs in response to specific failure conditions. 6 Reference Model and Defect Locations Figure 1 illustrates the PWE3 network reference model with an indication of the possible defect locations. This model will be referenced in the remainder of this document for describing the OAM procedures. ACs PSN tunnel ACs +----+ +----+ +----+ | PE1|==================| PE2| +----+ | |---(a)---(b)..(c)......PW1..(d)..(c)..(f)---(e)---| | | CE1| (N1) | | | | (N2) |CE2 | | |----------|............PW2.............|----------| | Nadeau, et al. Expires April 2005 [Page 4] Internet Draft draft-ietf-pwe3-oam-msg-map-01.txt October 2004 +----+ | |==================| | +----+ ^ +----+ +----+ ^ | Provider Edge 1 Provider Edge 2 | | | |<-------------- Emulated Service ---------------->| Customer Customer Edge 1 Edge 2 Figure 1: PWE3 Network Defect Locations The following is a brief description of the defect locations: (a) Defect in the first L2 network (N1). This covers any defect in the N1 which impacts all or a subset of ACs terminating in PE1. The defect is conveyed to PE1 and to the remote L2 network (N2) using a L2 specific OAM defect indication. (b) Defect on a PE1 AC interface. (c) Defect on a PE PSN interface. (d) Defect in the PSN network. This covers any defect in the PSN which impacts all or a subset of the PSN tunnels and PWs terminating in a PE. The defect is conveyed to the PE using a PSN and/or a PW specific OAM defect indication. Note that control plane, i.e., signaling and routing, messages do not necessarily follow the path of the user plane messages. Defect in the control plane are detected and conveyed separately through control plane mechanisms. However, in some cases, they have an impact on the status of the PW as explained in the next section. (e) Defect in the second L2 network (N2). This covers any defect in N2 which impacts all or a subset of ACs terminating in PE2. The defect is conveyed to PE2 and to the remote L2 network (N1) using a L2 specific OAM defect indication. (f) Defect on a PE2 AC interface. 7 PW Status and Defects This section describes possible PW defects, ways to detect them and consequent actions. 7.1 PW Defects Possible defects that impact PWs are the following. . Physical layer defect in the PSN interface . PSN tunnel failure which results in a loss of connectivity between ingress and egress PE . Control session failures between ingress and egress PE Nadeau, et al. Expires April 2005 [Page 5] Internet Draft draft-ietf-pwe3-oam-msg-map-01.txt October 2004 In case of an MPLS PSN and an MPLS-IP PSN there are additional defects: . PW labeling error, which is due to a defect in the ingress PE,or to an over-writing of the PW label value somewhere along the LSP path. . LSP tunnel Label swapping errors or LSP tunnel label merging errors in the MPLS network. This could result in the termination of a PW at the wrong egress PE. . Unintended self-replication; e.g., due to loops or denial-of- service attacks. 7.1.1 Packet Loss Persistent congestion in the PSN or in a PE could impact the proper operation of the emulated service. A PE can detect packet loss resulting from congestion through several methods. If a PE uses the sequence number field in the PWE3 Control Word for a specific Pseudo Wire [PWEARCH], it has the ability to detect packet loss. [CONGESTION] discusses other possible mechanisms to detect congestion between PWs. Generally, there are congestion alarms which are raised in the node and to the management system when congestion occurs. The decision to declare the PW Down and to re-signal it through another path is usually at the discretion of the network operator. 7.2 Defect Detection 7.2.1 Defect Detection Tools To detect the defects listed in 7.1, Service Providers have a variety of options available: Physical Layer defect detection mechanisms such as SONET/SDH LOS, LOF,and AIS/FERF. PSN Defect Detection Mechanisms: For PWE3 over an L2TP-IP PSN, with L2TP as encapsulation protocol, the defect detection mechanisms described in [L2TPv3] apply. Furthermore, the tools Ping and Traceroute, based on ICMP Echo Messages apply [ICMP]. For PWE3 over an MPLS PSN and an MPLS-IP PSN, several tools can be used. Nadeau, et al. Expires April 2005 [Page 6] Internet Draft draft-ietf-pwe3-oam-msg-map-01.txt October 2004 . LSP-Ping and LSP-Traceroute( [LSPPING]) for LSP tunnel connectivity verification. . LSP-Ping with Bi-directional Forwarding Detection ([BFD]) for LSP tunnel continuity checking. .Furthermore, if RSVP-TE is used to setup the PSN Tunnels between ingress and egress PE, the hello protocol can be used to detect loss of connectivity (see [RSVP-TE]), but only at the control plane. PW specific defect detection mechanisms: [VCCV] describes how LSP-Ping and BFD can be used over individual PWs for connectivity verification and continuity checking respectively. When used as such, we will refer to them as VCCV- Ping and VCCV-BFD respectively. 7.2.2 Defect Detection Mechanism Applicability The discussion below is intended to give some perspective how tools mentioned in the previous section can be used to detect failures. Observations: . Tools like LSP-Ping and BFD can be run periodically or on demand. If used for defect detection, as opposed to diagnostic usage, they must be run periodically. . Control protocol failure indications, e.g. detected through L2TP Keep-alive messages or the RSVP-TE Hello messages, can be used to detect many network failures. However, control protocol failures do not necessarily coincide with data plane failures. Therefore, a defect detection mechanism in the data plane is required to protect against all potential data plane failures. Furthermore, fault diagnosis mechanisms for data plane failures are required to further analyze detected failures. . For PWE3 over an MPLS PSN and an MPLS-IP PSN, it is effective to run a defect detection mechanism over a PSN Tunnel frequently and run one over every individual PW within that PSN Tunnel less frequently. However in case the PSN traffic is distributed over Equal Cost Multi Paths (ECMP), it may be difficult to guarantee that PSN OAM messages follow the same path as a specific PW. A Service Provider might therefore decide to focus on defect detection over PWs. . In MPLS networks, execution of LSP Ping would detect MPLS label errors, since it requests the receiving node to match the label with the original FEC that was used in the LSP set up. BFD can also be used since it relies on discriminators. A label error Nadeau, et al. Expires April 2005 [Page 7] Internet Draft draft-ietf-pwe3-oam-msg-map-01.txt October 2004 would result in a mismatch between the expected discriminator and the actual discriminator in the BFD control messages. . For PWE3 over an MPLS PSN and an MPLS-IP PSN, PEs could detect PSN label errors through the execution of LSP-Ping. However, use of VCCV is preferred as it is a more accurate detection tool for pseudowires. Furthermore, it can be run using a BFD mode, i.e., VCCV-BFD, which allows it to be used as a light-weight detection mechanism for PWs. If, due to a label error in the PSN, a PW would be terminated on the wrong egress PE, PEs would detect this through the execution of VCCV. LSP ping and/or LSP trace could then be used to diagnose the detected failure. Based on these observations, it is clear that a service provider has the disposal of a variety of tools. There are many factors that influence which combination of tools best meets its needs. 7.3 PW Defect Entry and Exit Procedures PWs can fail in a single direction or in both directions. PEs SHOULD keep track of the status of each individual direction. In other words, a PE SHOULD be able to distinguish between the following states: "PW UP", "PW Transmit Direction Down", "PW Receive Direction Down", "PW Receive and Transmit Down". The next two sections discuss under which conditions a PE enters and exits these states. To avoid an unnecessarily complicated description, only the states "PW UP" and "PW DOWN" are discussed without further analysis whether it applies to one or two directions of the PW. 7.3.1 PW Down A PE will consider a PW down if one of the following occurs . It detects a physical layer alarm on the PSN interface over which the PW is riding and cannot re-establish the PW over another PSN interface. . It detects loss of connectivity on the PSN tunnel over which the PW is riding. This includes label swapping errors and label merging errors. . It receives a message from its peer indicating a PW defect, which could be one of the following: o PW Status indicating "Local PSN-facing PW (ingress) Receive Receive Fault"; "Local PSN-facing PW (egress) Transmit Fault"; or "PW not forwarding" o In the case of an L2TP-IP, this is a L2TP StopCCN or CDN Nadeau, et al. Expires April 2005 [Page 8] Internet Draft draft-ietf-pwe3-oam-msg-map-01.txt October 2004 message. A StopCCN message indicates that the control connection has been shut down by the remote PE [L2TPv3]. This is typically used for defects in the PSN which impact both the control connection and the individual data plane sessions. On reception of this message, a PE closes the control connection and will clear all the sessions managed by this control connection. Since each session carries a single PW, the state of the corresponding PWs is changed to DOWN. A CDN message indicates that the remote peer requests the disconnection of a specific session [L2TPv3]. In this case only the state of the corresponding PW is changed to DOWN. This is typically used for local defects in a PE which impact only a specific session and the corresponding PW. o It detects a loss of PW connectivity, including label errors, through VCCV. Note that if the PW control session between the PEs fails, the PW is torn down and needs to be re-established. However, the consequent actions towards the ACs are the same as if the PW state were DOWN. 7.3.2 PW Up When a PE determines that all previously existing failures have disappeared, it SHOULD send a message to its peer to indicate this. E.g. if the original failure was conveyed through a PW Status message, the PE should send a PW Status message indicating "PW Forwarding (clear all failures)" When a PE receives a PW Status message indicating "PW Forwarding", while it still considers a PW down, and if all previously existing failures, if any, have disappeared, it SHOULD respond with a PW Status message indicating "PW Forwarding". For PWE3 over a MPLS PSN and a MPLS-IP PSN, a PE will exit the PW down state when the following conditions are true: . All defects it had previously detected, as described in Section 7.3.1, have disappeared, and . It has received a PW Status message from its peer indicating "PW Forwarding" For a PWE3 over a L2TP-IP PSN, a PE will exit the PW down state when the following conditions are true: . All defects it had previously detected, as described in Section 7.3.1, have disappeared, and . A L2TPv3 session is successfully established to carry the PW packets. Nadeau, et al. Expires April 2005 [Page 9] Internet Draft draft-ietf-pwe3-oam-msg-map-01.txt October 2004 [BFD] and [L2TPv3] define the procedures to exit the PW Down state if the original failure notification was done through BFD or L2TP messages, respectively. 7.4 Alarm Messages and Consequent Actions When a PE changes the status of a PW to DOWN, it SHOULD inform its peer, by using: . For PWE3 on an MPLS PSN or on an MPLS-IP PSN, PW Status messages as defined in [CONTROL]. . For PWE3 on L2TP-IP PSN, L2TPv3 messages Stop Control-Connection Notification (STOPCCN) and Call Disconnect Notify (CDN) as defined in [L2TPv3] Furthermore, in either case, if VCCV-BFD is used, the diagnostic code in the VCCV-BFD Control message can be used to exchange alarm information. In general, PW Status messages or L2TP STOPCCN and CDN should be used to communicate failures. VCCV-BFD alarm indications should only be used in specific cases, as explained in 4.6. Both PEs will translate the PW alarms to the appropriate failure indications on the affected ACs. The exact procedures depend on the emulated protocols and will be discussed in the next sections. 7.5 The Use of PW Status This document specifies the use of PW status signaling for the purpose of conveying the status of a PW and attached ACs between PEs. At the PW setup, a PE will enter in a negotiation with its remote peer of the use of the PW status by inserting the PW Status TLV in the label mapping message. If the negotiation process results in the usage of the PW status TLV, then the actual PW status is determined by the PW status TLV that was sent within the initial PW label mapping. Subsequent updates of PW status are conveyed through the notification message [CONTROL]. PW Status messages are used to report the following defects: . Defects detected through defect detection mechanisms in the MPLS or MPLS-IP PSN . Loss of connectivity detected through VCCV-Ping . Defects within the PE that result in an inability to forward traffic between ACs and PW Nadeau, et al. Expires April 2005 [Page 10] Internet Draft draft-ietf-pwe3-oam-msg-map-01.txt October 2004 If the PW defect is related to one forwarding direction only, the PE shall either use "Local PSN-facing PW (ingress) Receive Fault" or "Local PSN-facing PW (egress) Transmit Fault". In all other cases it shall use "PW Not Forwarding". Besides reporting PW defects, PW status is used to propagate AC defects. When and how to use those messages is dependent on the emulated protocol and will be explained in Section 8 and in subsequent sections.. 7.6 The Use of L2TP STOPCCN and CDN [L2TPv3] describes the use of STOPCCN and CDN messages to exchange alarm information between PEs. Like PW Status, STOPCCN and CDN messages shall be used to report the following failures: . Failures detected through defect detection mechanisms in the L2TP-IP PSN . Failures detected through VCCV (except for VCCV-BFD) . Failures within the PE that result in an inability to forward traffic between ACs and PW In L2TP, the Set-Link-Info (SLI) message is used to convey failures on the ACs. 7.7 The Use of BFD Diagnostic Codes [BFD] defines a set of diagnostic codes that partially overlap with failures that can be communicated through PW Status messages or L2TP STOPCCN and CDN messages. To avoid ambiguous situations, these messages SHOULD be used for all failures that are detected through means other than BFD. For VCCV-BFD, therefore, only the following diagnostic codes apply: Code Message ---- ------------------------------ 0 No Diagnostic 1 Control Detection Time Expired 3 Neighbor Signaled Session Down 7 Administratively Down [VCCV] states that, when used over PWs, the asynchronous mode of BFD should be used. Diagnostic code 2 (Echo Function Failed) does not apply to the asynchronous mode, but to the Demand Mode. All other BFD diagnostic codes refer to failures that can be communicated through PW Status or L2TP STOPCCN and CDN. Nadeau, et al. Expires April 2005 [Page 11] Internet Draft draft-ietf-pwe3-oam-msg-map-01.txt October 2004 The VCCV-BFD procedures are as follows: When the downstream PE (PE1) does not receive control messages from the upstream PE (PE2) during a certain number of transmission intervals (a number provisioned by the operator), it declares that the PW in its receive direction is down. PE1 sends a message to PE2 with H=0 (i.e. "I do not hear you") and with diagnostic code 1. In turn, PE2 declares the PW is down in its transmit direction and it uses diagnostic code 3 in its control messages to PE2. When a PW is taken administratively down, the PEs will exchange PW Status messages with code "Pseudo Wire Not Forwarding" or L2TP CDN messages with code "Session disconnected for administrative reasons". In addition, exchange of BFD control messages MUST be suspended. To that end, the PEs MUST send control messages with H=0 and diagnostic code 7. In conclusion, one would communicate PW defects through PW Status messages, or L2TP STOPCCN and CDN messages in all cases, except for a well-defined set of exceptions where BFD is used. How PW defects that can be detected through the use of BFD or through other means, are mapped to defect indications on the ACs is described in section 8 and in subsequent sections. 8 Frame Relay Encapsulation 8.1 Frame Relay Management The management of Frame Relay Bearer Service (FRBS) connections can be accomplished through two distinct methodologies: 1. Based on ITU-T Q.933 Annex A, Link Integrity Verification procedure, where STATUS and STATUS ENQUIRY signaling messages are sent using DLCI=0 over a given UNI and NNI physical link. [ITU-T Q.933] 2. Based on FRBS LMI, and similar to ATM ILMI where LMI is common in private Frame Relay networks. In addition, ITU-T I.620 addresses Frame Relay loopback, but the deployment of this standard is relatively limited. [ITU-T I.620] It is possible to use either, or both, of the above options to manage Frame Relay interfaces. This document will refer exclusively to Q.933 messages. The status of any provisioned Frame Relay PVC may be updated through: . STATUS messages in response to STATUS ENQUIRY messages, these are mandatory. Nadeau, et al. Expires April 2005 [Page 12] Internet Draft draft-ietf-pwe3-oam-msg-map-01.txt October 2004 . Optional unsolicited STATUS updates independent of STATUS ENQUIRY (typically under the control of management system, these updates can be sent periodically (continuous monitoring) or only upon detection of specific defects based on configuration. In Frame Relay, a DLC is either up or down. There is no distinction between different directions. 8.2 FR AC State A PE changes the state of an FR AC to DOWN if any of the following conditions are met: (i) A PVC is not ædeletedÆ from the Frame Relay network and the Frame Relay network explicitly indicates in a full status report (and optionally by the asynchronous status message) that this Frame Relay PVC is æinactiveÆ. In this case, this status maps across the PE to the corresponding PW only. (ii) The LIV indicates that the link from the PE to the Frame Relay network is down. In this case, the link down indication maps across the PE to all corresponding PWs. (iii) A physical layer alarm is detected on the FR interface. In this case, this status maps across the PE to all corresponding PWs. A PE exits the FR AC Down state when all defects it had previously detected have disappeared. 8.3 Mapping of Defect States from a PW to a Frame Relay AC The following are the OAM procedures for defects in locations (c) and (d) in Figure 1: a. PE1 MUST change the state of the affected PWs to DOWN for the direction of the defect. b. PE1 MUST generate a full status report with the Active bit = 0 (and optionally in the asynchronous status message), as per Q.933 annex A, into N1 for the corresponding FR ACs. c. If both directions of the PW are down, PE1 MUST generate a PW status message indicating ææPW not forwardingÆÆ. If only the Transmit direction is down, PE1 MUST generate a PW status message indicating ææLocal PSN-facing PW (egress) Transmit FaultÆÆ. d. If only the Receive direction of the PW is down, PE1 MUST generate a PW status message indicating ææLocal PSN-facing PW (ingress) Receive FaultÆÆ. e. On reception of the PW status message, PE2 MUST generate a full status report with the Active bit = 0 (and optionally in the asynchronous status message), as per Q.933 annex A, into N2 for the corresponding FR ACs. Nadeau, et al. Expires April 2005 [Page 13] Internet Draft draft-ietf-pwe3-oam-msg-map-01.txt October 2004 For PWE3 over L2TP-IP, the following operations MUST be performed when PE1 detects a defect in locations (c) or (d): a. PE1 MUST change the state of the affected PWs to DOWN for the direction of the defect. b. PE1 MUST generate a full status report with the Active bit = 0 (and optionally in the asynchronous status message), as per Q.933 annex A, into N1 for the corresponding FR ACs. c. PE1 MUST send an L2TPv3 CDN message or a StopCCN message. d. On reception of the CDN or StopCCN message, PE2 MUST generate a full status report with the Active bit = 0 (and optionally in the asynchronous status message), as per Q.933 annex A, into N2 for the corresponding FR ACs. When the PW state changes back to UP, a PE MUST generate a full status report (and optionally in the asynchronous status message), indicating a ææactiveÆÆ status for the corresponding FR AC. In addition, it MUST generate a PW Status message indicating ææPseudo Wire forwarding (clear all failures)ÆÆ for PWE3 over a MPLS PSN and a MPLS-IP PSN. For PWE3 or an L2TP-IP, the PW UP state is the result of the successful re-establishment of a L2TPv3 session to carry the PW packets. This will result in clearing the alarm states in the remote PE, in CE1, and in CE2 8.3.1 Procedures in FR Port Mode In case of pure port mode, STATUS ENQUIRY and STATUS messages are transported transparently over the PW. A PW Failure will therefore result in timeouts of the Q.933 link and PVC management protocol at the Frame Relay devices at one or both sites of the emulated interface. 8.4 Frame Relay Network and Attachment Circuit Defects The following are the OAM procedures for defects in locations (a) and (b) in Figure 1. The handling of a defect in locations (e) and (f) is similar to that of locations (a) and (b) respectively. As explained in [CONTROL], if a PE detects that a Frame Relay PVC is "inactive", as defined in [ITU-T Q933] Annex A.5, it will convey this information to its peer using a PW status message. The remote PE SHOULD generate the corresponding errors and alarms on the egress Frame Relay PVC For PWE3 over MPLS PSN or MPLS-IP PSN, a PE that detects or is notified of a defect in locations (a) or (b) MUST change the local state of the corresponding FR ACs to DOWN in PE1 and MUST send a PW Status message indicating both "AC Receive Fault" and "AC Transmit Fault". On reception of this PW status message, the egress PE MUST generate a full status report with the Active bit = Nadeau, et al. Expires April 2005 [Page 14] Internet Draft draft-ietf-pwe3-oam-msg-map-01.txt October 2004 0 (and optionally in the asynchronous status message), as per Q.933 annex A, into N2 for the corresponding FR ACs. For PWE3 over L2TP-IP PSN, a PE that detects or is notified of a defect in locations (a) or (b) MUST change the local state of the corresponding FR ACs to DOWN in PE1 and MUST send an L2TP Set-Link Info (LSI) message with a Circuit Status Attribute Value Pair (AVP) indicating "inactive". On reception of this LSI message, the egress PE MUST generate a full status report with the Active bit = 0 (and optionally in the asynchronous status message), as per Q.933 annex A, into N2 for the corresponding FR ACs. 9 ATM Encapsulation 9.1 ATM Management ATM management and OAM mechanisms are much more evolved than those of Frame Relay. There are five broad management-related categories, including fault management (FT), Performance management (PM), configuration management (CM), Accounting management (AC), and Security management (SM). ITU-T Recommendation I.610 describes the functions for the operation and maintenance of the physical layer and the ATM layer, that is, management at the bit and cell levels ([ITU-T I.610]). Because of its scope, this document will concentrate on ATM fault management functions. Fault management functions include the following: 1) Alarm indication signal (AIS) 2) Remote Defect indication (RDI). 3) Continuity Check (CC). 4) Loopback (LB) Some of the basic ATM fault management functions are described as follows: Alarm indication signal (AIS) sends a message in the same direction as that of the signal, to the effect that an error has been detected. Remote defect indication (RDI) sends a message to the transmitting terminal that an error has been detected. RDI is also referred to as the far-end reporting failure. Alarms related to the physical layer are indicated using path AIS/RDI. Virtual path AIS/RDI and virtual channel AIS/RDI are also generated for the ATM layer. OAM cells (F4 and F5 cells) are used for the control of virtual paths and virtual channels with regard to their performance and availability. F4 cells are used to monitor a VPC, F5 cells for a VCC. OAM cells in the F4 and F5 flows are used for monitoring a segment of the network and end-to-end monitoring. OAM cells in F4 flows have the same VPI as that of the connection being monitored. OAM cells in F5 flows have the same VPI and VCI as that of the connection being monitored. The AIS and RDI messages of the F4 and F5 flows are sent to the other network nodes via the VPC or Nadeau, et al. Expires April 2005 [Page 15] Internet Draft draft-ietf-pwe3-oam-msg-map-01.txt October 2004 the VCC to which the message refers. The type of error and its location can be indicated in the OAM cells. Continuity check is another fault management function. To check whether a VCC that has been idle for a period of time is still functioning, the network elements can send continuity-check cells along that VCC. 9.2 ATM AC State A PE changes the state of an ATM AC to DOWN if any of the following conditions are met: (i) It detects a physical layer alarm on the ATM interface or it receives a F4 AIS/RDI for a AC inside a terminating VP. (ii) It receives an F4/F5 AIS/RDI OAM cell indicating that the ATM VP/VC is down in the adjacent L2 ATM network (e.g., N1 for PE1). (iii) It detects loss of connectivity on the ATM VPC/VCC while running ATM continuity checking (ATM CC) with the local ATM network and CE. A PE exits the ATM AC Down state when all defects it had previously detected have disappeared. The exact conditions under which a PE exits a AIS or a RDI state, or declares that connectivity is restored via ATM CC are defined in I.610 [I.610]. 9.3 Mapping ATM and PW Defect States In normal, i.e., defect-free, operation, all the types of ATM OAM cells described in Section 9.1 are either terminated at the PE, for OAM segments terminating in the AC endpoint, or transparently carried over the PSN tunnel [PWE3-ATM]. This is referred to as ææinband ATM OAM over PWÆÆ and is the default method. An optional out-of band method based on relaying the ATM defect state over a PW specific defect indication mechanism is provided for PEÆs which cannot generate and/or transmit ATM OAM cells over the ATM PW. This is referred to as ææOut-of-band ATM OAM over PWÆÆ. Note that the out-of-band method assumes that the end-to-end circuit consists of three independent segments, , with defect states relayed across the boundary of these segments. An important consequence of this is that when a PE is notified of a defect in the remote ATM network, in the remote AC, or in the PW, it will always generate a F4/F5 AIS message towards the local ATM network and local CE regardless of the stated direction of the defect. At the same time, the PE should not relay over the PW the defect state of a received F4/F5 RDI from the local CE if it is sourcing a F4/F5 AIS on the same AC towards that CE. These conditions maintain the independence of the three defect loops while relaying the defect states end-to-end. The procedures in sections 9.4.2 and 9.5.2 satisfy these two conditions. Nadeau, et al. Expires April 2005 [Page 16] Internet Draft draft-ietf-pwe3-oam-msg-map-01.txt October 2004 9.4 Mapping of Defect States from a PW to a ATM AC The following are the OAM procedures for defects in locations (c) and (d) in Figure 1. 9.4.1 Inband ATM OAM over PW When PE1 detects a defect in locations (c) or (d) it MUST change the state of the affected PWs to DOWN for the direction of the defect. If both directions of the PW are down or if only the Receive direction of the PW is down, PE1 MUST generate F4/F5 AIS on the affected ACs to convey this status to the ATM network (N1) and CE1 [PWE3-ATM]. CE1 will reply with a F4/F5 RDI which gets forwarded by PE1 over the PW. PE2 will receive the RDI message only if the forwards direction of the PW, i.e., PE1-to-PE2, is not affected by the defect. In this case, PE2 MUST forward the RDI message to CE2 through the ATM network (N2). If only the PW Transmit direction is DOWN at PE1, this is generally detected by PE2 through a PSN or a PW continuity checking or connectivity verification mechanism as explained in Section 7.3.1. PE1 is notified through the return path of that specific mechanism. In this case, PE2 will follow the same procedures described above for a defect in the PW Receive direction. If however, PE1 detects the defect in the transmit direction through a time-out of a connectivity verification mechanism such as LSP-Ping or VCCV-Ping, it MUST generate a PW status message indicating ææLocal PSN-facing PW (egress) Transmit FaultÆÆ and forward it to PE2. On reception of this message, PE2 will follow the same procedures described above for a defect in the PW Receive direction. When the PW status changes back to UP, a PE MUST cease the generation of the F4/F5 messages on the AC towards the CE. This will result in clearing the AIS or RDI states in the remote PE, in CE1, and in CE2. 9.4.2 Out-of-Band ATM OAM over PW For PWE3 over an MPLS PSN or an MPLS-IP PSN, the following operations MUST be performed when PE1 detects a defect in locations (c) or (d): a. PE1 MUST change the state of the affected PWs to DOWN for the direction of the defect. b. If both directions of the PW are down, PE1 MUST generate a PW status message indicating ææPW not forwardingÆÆ.If only the Transmit direction is down, PE1 MUST generate a PW status message indicating ææLocal PSN-facing PW (egress) Transmit FaultÆÆ. In addition, PE1 MUST generate a F4/F5 RDI on the affected ACs to convey this status to the ATM network (N1) and CE1. Nadeau, et al. Expires April 2005 [Page 17] Internet Draft draft-ietf-pwe3-oam-msg-map-01.txt October 2004 c. If only the Receive direction of the PW is down, PE1 MUST generate a PW status message indicating ææLocal PSN-facing PW (ingress) Receive FaultÆÆ. In addition, PE1 MUST generate a F4/F5 AIS on the affected ACs to convey this status to the ATM network (N1) and CE1. d. CE1 replies with a F4/F5 RDI in response to a received F4/F5 AIS only. PE1 MUST terminate the F4/F5 RDI since it is sourcing a PW status message towards PE2. Note however that the RDI defect state is treated as a separate defect from the original PW defect state. e. On reception of a ææPW not forwardingÆÆ or a ææLocal PSN- facing PW (egress) Transmit FaultÆÆ status message, PE2 MUST generate a F4/F5 AIS on the related ATM ACs towards CE2. On reception of a ææLocal PSN-facing PW (ingress) Receive FaultÆÆ status message, PE2 MUST generate a F4/F5 RDI on the related ATM ACs towards CE2. f. The termination point of the ATM VCC or VPC in the far-end CE, i.e., CE2, generates a F4/F5 RDI in response to the received F4/F5 AIS only. PE2 MUST treat this as a separate defect from the original PW defect and MUST generate a PW status message indicating ææAC Transmit FaultÆÆ towards PE1.PE1 MUST terminate the received PW status message and does not perform any additional action since it is sourcing a F4/F5 RDI towards CE1. For PWE3 over L2TP-IP PSN, the following operations MUST be performed when PE1 detects a defect in locations (c) or (d): a. PE1 MUST change the status of the affected PWs to DOWN for both directions. b. PE1 MUST send an L2TPv3 STOPCCN or CDN message. c. PE1 MUST generate a F4/F5 AIS on the affected ACs to convey this status to the ATM network (N1) and CE1. d. CE1 replies with a F4/F5 RDI. PE1 MUST terminate the F4/F5 RDI since it has informed PE2 that it had disconnected the corresponding L2TPv3 sessions. e. On reception of the SSCN or CDN message, PE2 MUST generate a F4/F5 AIS on the related ATM ACs towards CE2. f. The termination point of the ATM VCC or VPC in the far-end CE, i.e., CE2, generates a F4/F5 RDI in response to the received F4/F5 AIS. PE2 MUST terminate the F4/F5 RDI since it has disconnected the corresponding L2TPv3 sessions. When the PW status changes back to UP, a PE MUST cease the generation of the F4/F5 messages on the AC towards the CE. In addition, it MUST generate a PW Status message indicating ææPseudo Wire forwarding (clear all failures)ÆÆ for PWE3 over a MPLS PSN and a MPLS-IP PSN. For PWE3 or an L2TP-IP PSN, the PW UP state is the result of the successful re-establishment of a L2TPv3 session to carry the PW packets.. This will result in clearing the AIS or RDI states in the remote PE, in CE1, and in CE2. Nadeau, et al. Expires April 2005 [Page 18] Internet Draft draft-ietf-pwe3-oam-msg-map-01.txt October 2004 9.4.3 Procedures in ATM Port Mode In case of transparent cell transport, i.e., "port mode", where the PE does not keep track of the status of individual ATM VPCs or VCCs, a PE does not know which VPCs and/or VCCs are active. In such a case there is a need for another defect indication mechanism on the AC. This is beyond the scope of this document. 9.5 ATM Network and Attachment Circuit Defects The following are the OAM procedures for defects in locations (a) and (b) in Figure 1. The handling of a defect in locations (e) and (f) is similar to that of locations (a) and (b) respectively. 9.5.1 Inband ATM OAM over PW PE1 MUST transparently carry the F4/F5 AIS or RDI cells received on the corresponding ATM AC (defect a) or the F4/F5 AIS generated locally (defect b) over the corresponding ATM PW. The termination point of the ATM VCC or VPC in the far-end CE, i.e., CE2, generates a F4/F5 RDI in response to a F4/F5 AIS. PE2 MUST forward the RDI over the PW and PE1 MUST forward it over the corresponding AC. CE1 does not reply to a received F4/F5 RDI message. 9.5.2 Out-of-Band ATM OAM over PW If PE1 cannot generate and/or transmit ATM OAM cells over the ATM PW, it may use the following procedure. For PWE3 over an MPLS PSN or an MPLS-IP PSN, the following operations MUST be performed when PE1 receives a F4/F5 AIS or RDI from the ATM network (defect a) or when it detects a defect in the Receive or Transmit direction of the ATM AC (defect b): a. PE1 MUST send a PW Status message indicating "AC Receive Fault" for a received F4/F5 AIS. b. PE1 MUST send a PW status message indicating "AC Transmit Fault" for a received F4/F5 RDI. c. PE1 MUST generate a F4/F5 RDI on the related ACs towards CE1 in response to a received F4/F5 AIS only. d. On reception of a "AC Receive Fault" status message, PE2 MUST generate a F4/F5 AIS on the related ATM ACs towards CE2. On reception of a ææAC Transmit FaultÆÆ status message, PE2 MUST generate a F4/F5 RDI on the related ATM ACs towards CE2. e. The termination point of the ATM VCC or VPC in the far- end, i.e., CE2, generates a F4/F5 RDI in response to the received F4/F5 AIS only. PE2 MUST treat this as a separate defect from the original remote AC defect and MUST generate a PW status message indicating ææAC Transmit FaultÆÆ towards PE1.PE1 MUST terminate the received PW Nadeau, et al. Expires April 2005 [Page 19] Internet Draft draft-ietf-pwe3-oam-msg-map-01.txt October 2004 status message and does not perform any additional action since it is sourcing a F4/F5 RDI towards CE1. For PEW3 over L2TP-IP PSN, the following operations MUST be performed when PE1 receives a F4/F5 AIS or RDI from the ATM network (defect a) or when it detects a defect in the Receive or Transmit direction of the ATM AC (defect b): a. PE1 MUST send an L2TP Set-Link Info (LSI) message with a Circuit Status AVP indicating "inactive". b. PE1 MUST generate a F4/F5 RDI on the related ACs towards CE1 in response to a received F4/F5 AIS only. c. On reception of the L2TP LSI message, PE2 MUST generate a F4/F5 AIS on the related ATM ACs towards CE2. d. The termination point of the ATM VCC or VPC in the far-end CE, i.e., CE2, generates a F4/F5 RDI in response to the received F4/F5 AIS. PE2 MUST treat this as a separate defect from the original remote AC defect and MUST generate an L2TP Set-Link Info (LSI) message with a Circuit Status AVP indicating "inactive" towards PE1. On its reception, PE1 MUST cease the generation of RDI and generate a F4/F5 AIS towards CE1. CE1 will reply with a F4/F5 RDI which if received by PE1 and is terminated since PE1 has already sent a LSI to inform PE2 of an AC defect. 9.5.3 Procedures in ATM Port Mode In case of transparent cell transport, i.e., "port mode", where the PE does not know which VCCs and/or VPCs are active, AIS/RDI messages are transparently propagated to the remote ATM network without PE intervention for defects in the ATM network (location a). For defects in the PE ATM AC interface ,location b, the PE MUST send a PW-STATUS message to its peer. How the peer propagates that message on its AC is beyond the scope of this document. 10 SONET Encapsulation (CEP) [CEP] discusses how Loss of Connectivity and other SONET/SDH protocol failures on the PW are translated to alarms on the ACs and vice versa. In essence, all defect management procedures are handled entirely in the emulated protocol. There is no need for an interaction between PW defect management and SONET layer defect management. 11 TDM Encapsulation From an OAM perspective, the PSN carrying a TDM PW provides the same function as that of SONET/SDH or ATM network carrying the same low-rate TDM stream. Hence the interworking of defect OAM is similar. For structure-agnostic TDM PWs, the TDM stream is to be carried transparently across the PSN, and this requires TDM OAM Nadeau, et al. Expires April 2005 [Page 20] Internet Draft draft-ietf-pwe3-oam-msg-map-01.txt October 2004 indications to be transparently transferred along with the TDM data. For structure-aware TDM PWs the TDM structure alignment is terminated at ingress to the PSN and regenerated at egress, and hence OAM indications may need to be signaled by special means. In both cases generation of the appropriate emulated OAM indication may be required when the PSN is at fault. Since TDM is a real-time signal, defect indications and performance measurements may be classified into two classes, urgent and deferrable. Urgent messages are those whose contents may not be significantly delayed with respect to the TDM data that they potentially impact, while deferrable messages may arrive at the far end delayed with respect to simultaneously generated TDM data. For example, a forward indication signifying that the TDM data is invalid (e.g. TDM loss of signal, or MPLS loss of packets) is only of use when received before the TDM data is to be played out towards the far end TDM system. It is hence classified as an urgent message, and we can not delegate its signaling to a separate maintenance or management flow. On the other hand, the forward loss of multiframe synchronization, and most reverse indications do not need to be acted upon before a particular TDM frame is played out. From the above discussion it is evident that the complete solution to OAM for TDM PWs needs to have at least two, and perhaps three components. The required functionality is transparent transfer of native TDM OAM and urgent transfer of indications (by flags) along with the impacted packets. Optionally there may be mapping between TDM and PSN OAM flows. TDM AIS generated in the TDM network due to a fault in that network is generally carried unaltered, although the TDM encapsulations allow for its suppression for bandwidth conservation purposes. Similarly, when the TDM loss of signal is detected at the PE, it will generally emulate TDM AIS. SAToP and the two structure-aware TDM encapsulations have converged on a common set of defect indication flags in the PW control word. When the PE detects or is informed of lack of validity of the TDM signal, it raises the local ("L") defect flag, uniquely identifying the defect as originating in the TDM network. The remote PE must ensure that TDM AIS is delivered to the remote TDM network. When the defect lies in the MPLS network, the remote PE fails to receive packets. The remote PE generates TDM AIS towards its TDM network, and in addition raises the remote defect ("R") flag in its PSN-bound packets, uniquely identifying the defect as originating in the PSN. Finally, defects in the remote TDM network that cause RDI generation in that network, may optionally be indicated by proper setting of the field of valid packets in the opposite direction. 12 Ethernet Encapsulation Nadeau, et al. Expires April 2005 [Page 21] Internet Draft draft-ietf-pwe3-oam-msg-map-01.txt October 2004 At this point in time, Ethernet OAM is not defined. Therefore, the procedures for mapping PW failures to Ethernet OAM messages and vice versa are currently rudimentary. 12.1 Ethernet AC State A PE changes the state of an Ethernet AC to DOWN if any of the following conditions are met: (i) A physical layer alarm is detected on the Ethernet interface. A PE exits the Ethernet AC Down state when all defects it had previously detected have disappeared. 12.2 Mapping of Defect States from a PW to a Ethernet AC The procedures are the same as those described in Section 8.3 for a FR encapsulation. The only difference is that there is no defect notification available on the Ethernet AC. If an egress PE determines that all ACs on a specific Ethernet physical interface are affected, it MAY propagate these alarms by bringing the entire physical interface down. 12.3 Frame Relay Network and Attachment Circuit Defects The procedures are the same as those described in Section 8.4 for a FR encapsulation. The only difference is that there is no defect notification available on the Ethernet AC. If an egress PE determines that all ACs on a specific Ethernet physical interface are affected, it MAY propagate these alarms by bringing the entire physical interface down. 13 Security Considerations The mapping messages described in this document do not change the security functions inherent in the actual messages. 14 Acknowledgments Hari Rakotoranto, Eric Rosen, Mark Townsley, Michel Khouderchah, Bertrand Duvivier, Vanson Lim and Chris Metz Cisco Systems 15 References [BFD] Katz, D., Ward, D., "Bidirectional Forwarding Detection", Internet Draft , May 2004 Nadeau, et al. Expires April 2005 [Page 22] Internet Draft draft-ietf-pwe3-oam-msg-map-01.txt October 2004 [CEP] Malis, A., et.al., "SONET/SDH Circuit Emulation over Packet (CEP)", Internet Draft , August 2004 [CONGESTION] Rosen, E., Bryant, S., Davie, B., "PWE3 Congestion Control Framework", Internet Draft , October 2004 [ICMP] Postel, J. "Internet Control Message Protocol" RFC 792 [ITU-T I.610] Recommendation I.610 "B-ISDN operation and maintenance principles and functions", February 1999 [ITU-T I.620] Recommendation I.620 "Frame relay operation and maintenance principles and functions", October 1996 [ITU-T Q.933] Recommendation Q.933 " ISDN Digital Subscriber Signalling System No. 1 (DSS1) “ Signalling specifications for frame mode switched and permanent virtual connection control and status monitoring" February 2003 [L2TPv3] Lau, J., et.al. " Layer Two Tunneling Protocol (Version 3", Internet Draft , June 2004 [LSPPING] Kompella, K., Pan, P., Sheth, N., Cooper, D., Swallow, G., Wadhwa, S., Bonica, R., " Detecting MPLS Data Plane Failures", Internet Draft < draft-ietf-mpls-lsp-ping-06.txt>, July 2004 [MPLS-in-IP] Worster. T., et al., ææEncapsulating MPLS in IP or Generic Routing Encapsulation (GRE)ÆÆ, draft-ietf-mpls-in-ip- or-gre-08.txt, June 2004. [OAM REQ] T. Nadeau et.al., "OAM Requirements for MPLS Networks", Internet Draft , September 2004 [PWEARCH] Bryant, S., Pate, P., "PWE3 Architecture", Internet Draft, < draft-ietf-pwe3-arch-07.txt>, March 2004 [PWEATM] Martini, L., et al., "Encapsulation Methods for Transport of ATM Cells/Frame Over IP and MPLS Networks", Internet Draft , Ocotber 2004 [PWREQ] Xiao, X., McPherson, D., Pate, P., "Requirements for Pseudo Wire Emulation Edge to-Edge (PWE3)", RFC 3916, September 2004 Nadeau, et al. Expires April 2005 [Page 23] Internet Draft draft-ietf-pwe3-oam-msg-map-01.txt October 2004 [RSVP-TE] Awduche, D., et.al. " RSVP-TE: Extensions to RSVP for LSP Tunnels", RFC 3209, December 2001 [VCCV] Nadeau, T., et al."Pseudo Wire Virtual Circuit Connection Verification (VCCV)", Internet Draft , June 2004. 16 Intellectual Property Disclaimer The IETF takes no position regarding the validity or scope of any intellectual property or other rights that might be claimed to pertain to the implementation or use of the technology described in this document or the extent to which any license under such rights might or might not be available; neither does it represent that it has made any effort to identify any such rights. Information on the IETF's procedures with respect to rights in standards-track and standards-related documentation can be found in BCP-11. Copies of claims of rights made available for publication and any assurances of licenses to be made available, or the result of an attempt made to obtain a general license or permission for the use of such proprietary rights by implementers or users of this specification can be obtained from the IETF Secretariat. The IETF invites any interested party to bring to its attention any copyrights, patents or patent applications, or other proprietary rights which may cover technology that may be required to practice this standard. Please address the information to the IETF Executive Director. 17 Full Copyright Statement "Copyright (C) The Internet Society (2004). This document is subject to the rights, licenses and restrictions contained in BCP 78, and except as set forth therein, the authors retain all their rights." "This document and the information contained herein are provided on an "AS IS" basis and THE CONTRIBUTOR, THE ORGANIZATION HE/SHE REPRESENTS OR IS SPONSORED BY (IF ANY), THE INTERNET SOCIETY AND THE INTERNET ENGINEERING TASK FORCE DISCLAIM ALL WARRANTIES, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE INFORMATION HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE." Nadeau, et al. Expires April 2005 [Page 24] Internet Draft draft-ietf-pwe3-oam-msg-map-01.txt October 2004 18 Authors' Addresses Thomas D. Nadeau Cisco Systems, Inc. 300 Beaverbrook Drive Boxborough, MA 01824 Phone: +1-978-936-1470 Email: tnadeau@cisco.com Monique Morrow Cisco Systems, Inc. Glatt-com CH-8301 Glattzentrum Switzerland Email: mmorrow@cisco.com Peter B. Busschbach Lucent Technologies 67 Whippany Road Whippany, NJ, 07981 Email: busschbach@lucent.com Mustapha Aissaoui Alcatel 600 March Rd Kanata, ON, Canada. K2K 2E6 Email: mustapha.aissaoui@alcatel.com Matthew Bocci Alcatel Voyager Place, Shoppenhangers Rd Maidenhead, Berks, UK SL6 2PJ Email: matthew.bocci@alcatel.co.uk David Watkinson Alcatel 600 March Rd Kanata, ON, Canada. K2K 2E6 Email: david.watkinson@alcatel.com Yuichi Ikejiri NTT Communications Corporation 1-1-6, Uchisaiwai-cho, Chiyoda-ku Nadeau, et al. Expires April 2005 [Page 25] Internet Draft draft-ietf-pwe3-oam-msg-map-01.txt October 2004 Tokyo 100-8019, JAPAN Email: y.ikejiri@ntt.com Kenji Kumaki KDDI Corporation KDDI Bldg. 2-3-2 Nishishinjuku, Shinjuku-ku Tokyo 163-8003,JAPAN E-mail : kekumaki@kddi.com Satoru Matsushima Japan Telecom JAPAN Email: satoru@ft.solteria.net David Allan Nortel Networks 3500 Carling Ave., Ottawa, Ontario, CANADA Email: dallan@nortelnetworks.com Nadeau, et al. Expires April 2005 [Page 26]