MPLS Working Group M. Bocci Internet-Draft Alcatel-Lucent Intended status: Standards Track G. Swallow Expires: January 13, 2011 Cisco July 12, 2010 MPLS-TP Identifiers draft-ietf-mpls-tp-identifiers-02 Abstract This document specifies identifiers for MPLS-TP objects. Included are identifiers conformant to existing ITU conventions and identifiers which are compatible with existing IP, MPLS, GMPLS, and Pseudowire definitions. Status of this Memo This Internet-Draft is submitted in full conformance with the provisions of BCP 78 and BCP 79. Internet-Drafts are working documents of the Internet Engineering Task Force (IETF). Note that other groups may also distribute working documents as Internet-Drafts. The list of current Internet- Drafts is at http://datatracker.ietf.org/drafts/current/. 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." This Internet-Draft will expire on January 13, 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. Bocci & Swallow Expires January 13, 2011 [Page 1] Internet-Draft MPLS-TP Identifiers July 2010 Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3 1.1. Terminology . . . . . . . . . . . . . . . . . . . . . . . 3 2. Named Entities . . . . . . . . . . . . . . . . . . . . . . . . 4 3. Uniquely Identifying an Operator . . . . . . . . . . . . . . . 5 3.1. The Global ID . . . . . . . . . . . . . . . . . . . . . . 5 3.2. ITU Carrier Code . . . . . . . . . . . . . . . . . . . . . 5 4. Node and Interface Identifiers . . . . . . . . . . . . . . . . 6 5. MPLS-TP Tunnel and LSP Identifiers . . . . . . . . . . . . . . 7 5.1. MPLS-TP Point to Point Tunnel Identifiers . . . . . . . . 7 5.2. MPLS-TP LSP Identifiers . . . . . . . . . . . . . . . . . 8 5.3. Mapping to GMPLS Signalling . . . . . . . . . . . . . . . 8 6. Pseudowire Path Identifiers . . . . . . . . . . . . . . . . . 9 7. Maintenance Identifiers . . . . . . . . . . . . . . . . . . . 9 7.1. Maintenance Entity Group Identifiers . . . . . . . . . . . 10 7.1.1. ICC based MEG_IDs . . . . . . . . . . . . . . . . . . 10 7.1.2. IP Compatible MEG_IDs . . . . . . . . . . . . . . . . 10 7.1.2.1. MPLS-TP LSP MEG_IDs . . . . . . . . . . . . . . . 10 7.1.2.2. Pseudowire MEG_IDs . . . . . . . . . . . . . . . . 10 7.2. MEP_IDs . . . . . . . . . . . . . . . . . . . . . . . . . 11 7.2.1. ICC based MEP_IDs . . . . . . . . . . . . . . . . . . 11 7.2.2. IP based MEP_IDs . . . . . . . . . . . . . . . . . . . 11 7.2.2.1. MPLS-TP LSP_MEP_ID . . . . . . . . . . . . . . . . 11 7.2.2.2. MEP_IDs for Pseudowires . . . . . . . . . . . . . 11 7.2.2.3. Endpoint IDs for Pseudowire Segments . . . . . . . 12 7.3. MIP_IDs . . . . . . . . . . . . . . . . . . . . . . . . . 12 8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 13 9. Security Considerations . . . . . . . . . . . . . . . . . . . 13 10. References . . . . . . . . . . . . . . . . . . . . . . . . . . 13 10.1. Normative References . . . . . . . . . . . . . . . . . . . 13 10.2. Informative References . . . . . . . . . . . . . . . . . . 14 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 14 Bocci & Swallow Expires January 13, 2011 [Page 2] Internet-Draft MPLS-TP Identifiers July 2010 1. Introduction This document specifies identifiers to be used in within the Transport Profile of Multiprotocol Label Switching (MPLS-TP). The MPLS-TP requirements [12] require that the elements and objects in an MPLS-TP environment are able to be configured and managed without a control plane. In such an environment many conventions for defining identifiers are possible. This document defines identifiers for MPLS-TP management and OAM functions suitable to ITU conventions and to IP/MPLS conventions. Applicability of the different identifier schemas to different applications are outside the scope of this document. 1.1. Terminology AII: Attachment Interface Identifier AP: Attachment Point ASN: Autonomous System Number FEC: Forwarding Equivalence Class GMPLS: Generalized Multi-Protocol Label Switching ICC: ITU Carrier Code LSP: Label Switched Path LSR: Label Switching Router ME: Maintenance Entity MEG: Maintenance Entity Group MEP: Maintenance Entity Group End Point MIP: Maintenance Entity Group Intermediate Point MPLS: Multi-Protocol Label Switching OAM: Operations, Administration and Maintenance P2MP: Point to Multi-Point P2P: Point to Point PW: Pseudowire Bocci & Swallow Expires January 13, 2011 [Page 3] Internet-Draft MPLS-TP Identifiers July 2010 RSVP: Resource Reservation Protocol RSVP-TE: RSVP Traffic Engineering S-PE: Switching Provider Edge T-PE: Terminating Provider Edge Requirements Language 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 [1]. Notational Conventions in Backus-Naur Form All multiple-word atomic identifiers use underscores (_) between the words to join the words. Many of the identifiers are composed of a concatenation of other identifiers, these are expressed using Backus- Naur Form. Where the same identifier is used multiple times in a concatenation, they are qualified by a prefix joining it to the identifier by a dash (-). For example Src-Node_ID is the Node_ID of a node referred to as Src (short for source). 2. Named Entities In order to configure, operate and manage a transport network based on the MPLS Transport Profile, a number of entities require identification. Identifiers for the follow entities are defined in this document: o Operator * Global_ID * ICC o LSR o LSP o PW o Interface o MEG Bocci & Swallow Expires January 13, 2011 [Page 4] Internet-Draft MPLS-TP Identifiers July 2010 o MEP o MIP o Tunnel Note that we have borrowed the term tunnel from RSVP-TE (RFC 3209) [2] where it is used to describe an entity that provides a connection between a source and destination LSR. The tunnel in turn is instantiated by one or more LSPs, where the additional LSPs are used for protection or re-grooming of the tunnel. 3. Uniquely Identifying an Operator Two forms of identification are defined, one that is compatible with IP operational practice called a Global_ID and one compatible with ITU practice, the ICC. An Operator MAY be identified either by its Global_ID or by its ICC. 3.1. The Global ID RFC 5003 [3] defines a globally unique Attachment Interface Identifier (AII). That AII is composed of three parts, a Global_ID which uniquely identifies a operator, a prefix, and finally and attachment circuit identifier. We have chosen to use that Global ID for MPLS-TP. Quoting from RFC 5003, section 3.2, "The global ID can contain the 2-octet or 4-octet value of the operator's Autonomous System Number (ASN). It is expected that the global ID will be derived from the globally unique ASN of the autonomous system hosting the PEs containing the actual AIIs. The presence of a global ID based on the operator's ASN ensures that the AII will be globally unique." When the Global_ID is derived from a 2-octet AS number, the two high- order octets of this 4-octet identifier MUST be set to zero. Note that this Global_ID is used solely to provide a globally unique context for other MPLS-TP identifiers. It has nothing to do with the use of the ASN in protocols such as BGP. 3.2. ITU Carrier Code M.1400 defines the ITU Carrier Code (ICC) assigned to a network operator/service provider and maintained by the ITU-T Telecommunication Standardization Bureau (TSB): www.itu.int/ITU-T/ inr/icc/index.html. Bocci & Swallow Expires January 13, 2011 [Page 5] Internet-Draft MPLS-TP Identifiers July 2010 ICCs can be assigned both to ITU-T and non-ITU-T members and the referenced local ICC website may contain ICCs of operators of both kinds. The ICC is a string of one to six characters, each character being either alphabetic (i.e. A-Z) or numeric (i.e. 0-9) characters. Alphabetic characters in the ICC SHOULD be represented with upper case letters. 4. Node and Interface Identifiers An LSR requires identification of the node itself and of its interfaces. An interface is the Access Point (AP) to a server layer MPLS-TP section or MPLS-TP tunnel. We call the identifier associated with a node a Node Identifier (Node_ID). The Node_ID is a unique 32-bit unsigned integer assigned by the operator within the scope of the Global_ID. The value 0 (or 0.0.0.0 in dotted decimal notation) is reserved MUST NOT be used. The Node_ID is not an IPv4 address. However, it was chosen to be 32- bits to allow compatibility with existing MPLS deployments. In existing MPLS deployments LSRs are generally identified by an IPv4 loopback address. Where IPv4 addresses are in use the Node_ID MAY be automatically mapped to the LSR's /32 IPv4 loopback address. Note that, when IP reachability is not needed, the 32-bit Node_ID is not required to have any association with the IPv4 address space used in the operator's IGP or BGP. In situations where a Node_ID needs to be globally unique, this is accomplished by prefixing the identifier with the operator's Global_ID. The combination of Global_ID::Node_ID we call an Global Node ID or Global_Node_ID. Within the context of a particular node, we call the identifier associated with an interface an Interface Number or IF_Num. The IF_Num is a 32-bit unsigned integer assigned by the operator and MUST be unique within the scope of a Node_ID. The IF_Num value 0 has special meaning (see section Section 7.3 and must not be used as the IF_Num in an MPLS-TP IF_ID. An Interface Identifier or IF_ID identifies an interface uniquely within the context of a Global_ID. It is formed by concatenating the Node_ID with the IF_Num. That is an IF_ID is a 64-bit identifier formed as Node_ID::IF_Num. This convention was chosen to allow compatibility with GMPLS. GMPLS signaling [4] requires interface identification. GMPLS allows three Bocci & Swallow Expires January 13, 2011 [Page 6] Internet-Draft MPLS-TP Identifiers July 2010 formats for the Interface_ID. The third format consists of an IPv4 Address plus a 32-bit unsigned integer for the specific interface. The format defined for MPLS-TP is consistent with this format, but uses the Node_ID instead of an IPv4 Address. An IF_ID needs to be globally unique, this is accomplished by prefixing the identifier with the operator's Global_ID. The combination of Global_ID::Node_ID::IF_Num we call an Global Interface ID or Global_IF_ID. The attachment point to an MPLS-TP Tunnel (see section Section 5.1 also needs an interface identifier. A procedure for automatically generating these is contained in that section. 5. MPLS-TP Tunnel and LSP Identifiers A important construct within MPLS_TP is a connection which is provided across a working and a protection LSP. Within this document we will use the term MPLS-TP Tunnel or simply tunnel for the connection provided by the working and protect LSPs. This section defines an MPLS-TP Tunnel_ID to uniquely identify a tunnel and MPLS-TP LSP_IDs within the context of a tunnel. 5.1. MPLS-TP Point to Point Tunnel Identifiers At each endpoint a tunnel is uniquely identified by the endpoint's Node_ID and a locally assigned tunnel number. Specifically a Tunnel_Num is a 16-bit unsigned integer unique within the context of the node. The motivation for each endpoint having its own tunnel number is to allow a compact form for the MEP-ID. See section Section 7.1.2.1. Having two tunnel-ids also serves to simplify other signaling. For instance an associated bi-directional tunnel could be setup using two unidirectional tunnels signaled via RSVP. The concatenation of the two endpoint identifier servers as the full identifier. In a signaled situation, the node originating the signaling exchange is called the source and the target node is called the destination. In a configured environment the endpoints could equally be called East and West. Using the signaled convention and abbreviating the endpoint qualifiers to Src and Dst respectively, the format of the format of a Tunnel_ID is: Src-Node_ID::Src-Tunnel_Num::Dst-Node_ID::Dst-Tunnel_Num Where the Tunnel_ID needs to be globally unique, this is accomplished Bocci & Swallow Expires January 13, 2011 [Page 7] Internet-Draft MPLS-TP Identifiers July 2010 by using globally unique Node_IDs as defined above. Thus a globally unique Tunnel_ID becomes: Src-Global_Node_ID::Src-Tunnel_Num::Dst-Global_Node_ID:: Dst-Tunnel_Num When an MPLS-TP Tunnel is configured, it MUST be assigned a unique IF_ID at both the source and destination endpoints. As usual, the IF_ID is composed of the local NODE_ID concatenated with a 32-bit IF_Num. It is RECOMMENDED that the IF_Num be auto-generated by adding 2^31 to the local Tunnel_Num. 5.2. MPLS-TP LSP Identifiers Within the scope of an MPLS-TP Tunnel_ID an LSP can be uniquely identified by a single LSP number. Specifically an LSP_Num is a 16- bit unsigned integer unique within the Tunnel_ID. Thus the format of a LSP_ID is: Src-Node_ID::Src-Tunnel_Num::Dst-Node_ID::Dst-Tunnel_Num::LSP_Num Where the LSP_ID needs to be globally unique, this is accomplished by using globally unique Node_IDs as defined above. Thus a globally unique Tunnel_ID becomes: Src-Global_Node_ID::Src-Tunnel_Num::Dst-Global_Node_ID:: Dst-Tunnel_Num::LSP_Num 5.3. Mapping to GMPLS Signalling This section defines the mapping from an MPLS-TP LSP_ID to GMPLS. At this time, GMPLS has yet to be extended to accommodate Global_IDs. Thus a mapping is only made for the network unique form of the LSP_ID. GMPLS signaling [5] uses a 5-tuple to uniquely identify an LSP within a operator's network. This tuple is composed of a Tunnel Endpoint Address, Tunnel_ID, Extended Tunnel ID, and Tunnel Sender Address and (GMPLS) LSP_ID. In situations where a mapping to the GMPLS 5-tuple is required, the following mapping is used. o Tunnel Endpoint Address = Dst-Node_ID o Tunnel_ID = Src-Tunnel_Num Bocci & Swallow Expires January 13, 2011 [Page 8] Internet-Draft MPLS-TP Identifiers July 2010 o Extended Tunnel_ID = Src-Node_ID o Tunnel Sender Address = Src-Node_ID o LSP_ID = LSP_Num 6. Pseudowire Path Identifiers Pseudowire signaling (RFC 4447 [6]) defines two FECs used to signal pseudowires. Of these, FEC Type 129 along with AII Type 2 as defined in RFC 5003 [3] fits the identification requirements of MPLS-TP. In an MPLS-TP environment, a PW is identified by a set of identifiers which can be mapped directly to the elements required by FEC 129 and AII Type 2. To distinguish this identifier from other Pseudowire Identifiers, we call this a Pseudowire Path Identifier or PW_Path_Id. The AII Type 2 is composed of three fields. These are the Global_ID, the Prefix, and the AC_ID. The Global_ID used in this document is identical to the Global_ID defined in RFC 5003. The Node_ID is used as the Prefix. The AC_ID is as defined in RFC 5003. To complete the FEC 129, all that is required is a Attachment Group Identifier (AGI). That field is exactly as specified in RFC 4447. FEC 129 has a notion of Source AII (SAII) and Target AII (TAII). These terms are used relative to the direction of the signaling. In a purely configured environment when referring to the entire PW, this distinction is not critical. That is a FEC 129 of AGIa::AIIb::AIIc is equivalent to AGIa::AIIc::AIIb. We note that in a signaled environment, the required convention in RFC 4447 is that at a particular endpoint, the AII associated with that endpoint comes first. The complete PW_Path_Id is: AGI:Src-Global_ID::Src-Node_ID::Src-AC_ID::Dst-Global_ID:: Dst-Node_ID::Dst-AC_ID. 7. Maintenance Identifiers In MPLS-TP a Maintenance Entity Group (MEG) represents an Entity that requires management and defines a relationship between a set of maintenance points. A maintenance point is either Maintenance Entity Group End-point (MEP) or a Maintenance Entity Group Intermediate Point (MIP). Maintenance points are uniquely associated with a MEG. Within the context of a MEG, MEPs and MIPs must be uniquely identified. This section defines a means of uniquely identifying Maintenance Entity Groups, Maintenance Entities and uniquely defining Bocci & Swallow Expires January 13, 2011 [Page 9] Internet-Draft MPLS-TP Identifiers July 2010 MEPs and MIPs within the context of a Maintenance Entity Group. Note that depending on the requirements of a particular OAM interaction, the MPLS-TP maintenance entity context may be provided either explicitly using the MEG_IDs described above or implicitly by the label of the received OAM message. 7.1. Maintenance Entity Group Identifiers Maintenance Entity Group Identifiers (MEG_IDs) are required for MPLS-TP LSPs and Pseudowires. Two classes of MEG_IDs are defined, one that follows the IP compatible identifier defined above as well as the ICC-format. 7.1.1. ICC based MEG_IDs MEG_ID for MPLS-TP LSPs and Pseudowires MAY use the globally unique ICC-based format. In this case, the MEG_ID is a string of up to thirteen characters, each character being either alphabetic (i.e. A-Z) or numeric (i.e. 0-9) characters. It consists of two subfields: the ICC (as defined in section 3) followed by a unique MEG code (UMC). The UMC MUST be unique within the organization identified by the ICC. The ICC MEG_ID may be applied equally to a single MPLS-TP LSP or Pseudowires. Note that when encoded in a protocol such as in a TLV, a different type needs to be defined for LSP and PWs as the OAM capabilities may be different. 7.1.2. IP Compatible MEG_IDs 7.1.2.1. MPLS-TP LSP MEG_IDs Since a MEG pertains to a single MPLS-TP LSP, IP compatible MEG_IDs for MPLS-TP LSPs are simply the corresponding LSP_IDs. We note that while the two identifiers are syntactically identical, they have different semantics. This semantic difference needs to be made clear. For instance if both a MPLS-TP LSP_ID and MPLS-TP LSP MEG_IDs are to be encoded in TLVs different types need to be assigned for these two identifiers. 7.1.2.2. Pseudowire MEG_IDs For Pseudowires a MEG pertains to a single PW. The IP compatible MEG_ID for a PW is simply the corresponding PW_Path_ID. We note that while the two identifiers are syntactically identical, they have different semantics. This semantic difference needs to be made Bocci & Swallow Expires January 13, 2011 [Page 10] Internet-Draft MPLS-TP Identifiers July 2010 clear. For instance if both a PW_Path_ID and a PW_MEG_ID is to be encoded in TLVs different types need to be assigned for these two identifiers. 7.2. MEP_IDs 7.2.1. ICC based MEP_IDs ICC-based MEP_IDs for MPLS-TP LSPs and Pseudowires are formed by appending a unique number to the MEG_ID defined in section Section 7.1.1 above. Within the context of a particular MEG, we call the identifier associated with a MEP the MEP Index (MEP_Index). The MEP_Index is administratively assigned. It is encoded as a 16-bit unsigned integer and MUST be unique within the MEG. An ICC-based MEP_ID is: MEG_ID::MEP_Index An ICC-based MEP ID is globally unique by construction given the ICC- based MEG_ID global uniqueness. 7.2.2. IP based MEP_IDs 7.2.2.1. MPLS-TP LSP_MEP_ID In order to automatically generate MEP_IDs for MPLS-TP LSPs, we use the elements of identification that are unique to an endpoint. This ensures that MEP_IDs are unique for all LSPs within a operator. When Tunnels or LSPs cross operator boundaries, these are made unique by pre-pending them with the operator's Global_ID. The MPLS-TP LSP_MEP_ID is Node_ID::Tunnel_Num::LSP_Num, where the Node_ID is the node in which the MEP is located and Tunnel_Num is the tunnel number unique to that node. In situations where global uniqueness is required this becomes: Src-Global_ID::Src-Node_ID::Src-Tunnel_Num::LSP_Num 7.2.2.2. MEP_IDs for Pseudowires Like MPLS-TP LSPs, Pseudowire endpoints (T-PEs) require MEP_IDs. In order to automatically generate MEP_IDs for PWs, we simply use the AGI plus the AII associated with that end of the PW. Thus a MEP_ID used in end-to-end for an Pseudowire T-PE takes the form Bocci & Swallow Expires January 13, 2011 [Page 11] Internet-Draft MPLS-TP Identifiers July 2010 AGI:Src-Global_ID::Src-Node_ID::Src-AC_ID, where the Node_ID is the node in which the MEP is located and Tunnel_Num is the tunnel number unique to that node. 7.2.2.3. Endpoint IDs for Pseudowire Segments In some OAM communications, messages are originated by the node at one end of a PW segment and relayed to the other end by setting the TTL of the PW label to one. The MEP_ID Is Formed by a combination of a PW MEP_ID and the identification of the local node. At an S-PE, there are two PW segments. We distinguish the segments by using the MEP_ID which is upstream of the PW segment in question. To complete the identification we suffix this with the identification of the local node. +-------+ +-------+ +-------+ +-------+ | | | | | | | | | A|---------|B C|---------|D E|---------|F | | | | | | | | | +-------+ +-------+ +-------+ +-------+ T-PE1 S-PE2 S-PE3 T-PE4 Pseudowire Maintenance Points For example, suppose that in the above figure all of the nodes have Global_ID GID1; the node are represented as named in the figure; and The identification for the Pseudowire is: AGI = AGI1 Src-Global_ID = GID1 Src-Node_ID = T-PE1 Src-AC_ID = AII1 Dst-Global_ID = GID1 Dst-Node_ID = T-PE1 Dst-AC_ID = AII4 The PW segment endpoint at point A would be AGI1::GID1:T-PE1::AII1. The MP_ID at point C would be AGI1::GID1:T-PE1::AII1::GID1:S-PE2. 7.3. MIP_IDs At a cross connect point, in order to automatically generate MIP_IDs for MPLS-TP, we simply use the IF_IDs of the two interfaces which are Bocci & Swallow Expires January 13, 2011 [Page 12] Internet-Draft MPLS-TP Identifiers July 2010 cross connected via the label bindings of the MPLS-TP LSP. If only one MIP is configured, then the MIP_ID is formed using the Node_ID and an IF_Num of 0. In some contexts, such as LSP Ping[13], the Node_ID alone may be used as the MIP_ID. 8. IANA Considerations 9. Security Considerations 10. References 10.1. Normative References [1] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, March 1997. [2] Awduche, D., Berger, L., Gan, D., Li, T., Srinivasan, V., and G. Swallow, "RSVP-TE: Extensions to RSVP for LSP Tunnels", RFC 3209, December 2001. [3] Metz, C., Martini, L., Balus, F., and J. Sugimoto, "Attachment Individual Identifier (AII) Types for Aggregation", RFC 5003, September 2007. [4] Berger, L., "Generalized Multi-Protocol Label Switching (GMPLS) Signaling Functional Description", RFC 3471, January 2003. [5] Berger, L., "Generalized Multi-Protocol Label Switching (GMPLS) Signaling Resource ReserVation Protocol-Traffic Engineering (RSVP-TE) Extensions", RFC 3473, January 2003. [6] Martini, L., Rosen, E., El-Aawar, N., Smith, T., and G. Heron, "Pseudowire Setup and Maintenance Using the Label Distribution Protocol (LDP)", RFC 4447, April 2006. [7] Kompella, K., Rekhter, Y., and A. Kullberg, "Signalling Unnumbered Links in CR-LDP (Constraint-Routing Label Distribution Protocol)", RFC 3480, February 2003. [8] Kompella, K., Rekhter, Y., and L. Berger, "Link Bundling in MPLS Traffic Engineering (TE)", RFC 4201, October 2005. [9] Lang, J., Rekhter, Y., and D. Papadimitriou, "RSVP-TE Extensions in Support of End-to-End Generalized Multi-Protocol Label Switching (GMPLS) Recovery", RFC 4872, May 2007. Bocci & Swallow Expires January 13, 2011 [Page 13] Internet-Draft MPLS-TP Identifiers July 2010 [10] Aggarwal, R., Kompella, K., Nadeau, T., and G. Swallow, "BFD For MPLS LSPs", draft-ietf-bfd-mpls-07 (work in progress), June 2008. [11] Nadeau, T. and C. Pignataro, "Bidirectional Forwarding Detection (BFD) for the Pseudowire Virtual Circuit Connectivity Verification (VCCV)", draft-ietf-pwe3-vccv-bfd-07 (work in progress), July 2009. 10.2. Informative References [12] Vigoureux, M. and D. Ward, "Requirements for OAM in MPLS Transport Networks", draft-ietf-mpls-tp-oam-requirements-06 (work in progress), March 2010. [13] Kompella, K. and G. Swallow, "Detecting Multi-Protocol Label Switched (MPLS) Data Plane Failures", RFC 4379, February 2006. [14] Ohta, H., "Assignment of the 'OAM Alert Label' for Multiprotocol Label Switching Architecture (MPLS) Operation and Maintenance (OAM) Functions", RFC 3429, November 2002. [15] Niven-Jenkins, B., Brungard, D., Betts, M., Sprecher, N., and S. Ueno, "MPLS-TP Requirements", draft-ietf-mpls-tp-requirements-10 (work in progress), August 2009. [16] Bocci, M., Bryant, S., Frost, D., Levrau, L., and L. Berger, "A Framework for MPLS in Transport Networks", draft-ietf-mpls-tp-framework-12 (work in progress), May 2010. Authors' Addresses Matthew Bocci Alcatel-Lucent Voyager Place, Shoppenhangers Road Maidenhead, Berks SL6 2PJ UK Email: matthew.bocci@alcatel-lucent.com George Swallow Cisco Email: swallow@cisco.com Bocci & Swallow Expires January 13, 2011 [Page 14]