GENWiki

Premier IT Outsourcing and Support Services within the UK

User Tools

Site Tools


rfc:rfc7439

Internet Engineering Task Force (IETF) W. George, Ed. Request for Comments: 7439 Time Warner Cable Category: Informational C. Pignataro, Ed. ISSN: 2070-1721 Cisco

                                                          January 2015
         Gap Analysis for Operating IPv6-Only MPLS Networks

Abstract

 This document reviews the Multiprotocol Label Switching (MPLS)
 protocol suite in the context of IPv6 and identifies gaps that must
 be addressed in order to allow MPLS-related protocols and
 applications to be used with IPv6-only networks.  This document is
 intended to focus on gaps in the standards defining the MPLS suite,
 and is not intended to highlight particular vendor implementations
 (or lack thereof) in the context of IPv6-only MPLS functionality.
 In the data plane, MPLS fully supports IPv6, and MPLS labeled packets
 can be carried over IPv6 packets in a variety of encapsulations.
 However, support for IPv6 among MPLS control-plane protocols, MPLS
 applications, MPLS Operations, Administration, and Maintenance (OAM),
 and MIB modules is mixed, with some protocols having major gaps.  For
 most major gaps, work is in progress to upgrade the relevant
 protocols.

Status of This Memo

 This document is not an Internet Standards Track specification; it is
 published for informational purposes.
 This document is a product of the Internet Engineering Task Force
 (IETF).  It represents the consensus of the IETF community.  It has
 received public review and has been approved for publication by the
 Internet Engineering Steering Group (IESG).  Not all documents
 approved by the IESG are a candidate for any level of Internet
 Standard; see Section 2 of RFC 5741.
 Information about the current status of this document, any errata,
 and how to provide feedback on it may be obtained at
 http://www.rfc-editor.org/info/rfc7439.

George & Pignataro Informational [Page 1] RFC 7439 IPv6-Only MPLS January 2015

Copyright Notice

 Copyright (c) 2015 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.

George & Pignataro Informational [Page 2] RFC 7439 IPv6-Only MPLS January 2015

Table of Contents

 1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   4
 2.  Use Case  . . . . . . . . . . . . . . . . . . . . . . . . . .   4
 3.  Gap Analysis  . . . . . . . . . . . . . . . . . . . . . . . .   5
   3.1.  MPLS Data Plane . . . . . . . . . . . . . . . . . . . . .   6
   3.2.  MPLS Control Plane  . . . . . . . . . . . . . . . . . . .   6
     3.2.1.  Label Distribution Protocol (LDP) . . . . . . . . . .   6
     3.2.2.  Multipoint LDP (mLDP) . . . . . . . . . . . . . . . .   6
     3.2.3.  RSVP - Traffic Engineering (RSVP-TE)  . . . . . . . .   7
       3.2.3.1.  Interior Gateway Protocol (IGP) . . . . . . . . .   8
       3.2.3.2.  RSVP-TE Point-to-Multipoint (P2MP)  . . . . . . .   8
       3.2.3.3.  RSVP-TE Fast Reroute (FRR)  . . . . . . . . . . .   8
     3.2.4.  Path Computation Element (PCE)  . . . . . . . . . . .   8
     3.2.5.  Border Gateway Protocol (BGP) . . . . . . . . . . . .   9
     3.2.6.  Generalized Multi-Protocol Label Switching (GMPLS)  .   9
   3.3.  MPLS Applications . . . . . . . . . . . . . . . . . . . .   9
     3.3.1.  Layer 2 Virtual Private Network (L2VPN) . . . . . . .   9
       3.3.1.1.  Ethernet VPN (EVPN) . . . . . . . . . . . . . . .  10
     3.3.2.  Layer 3 Virtual Private Network (L3VPN) . . . . . . .  10
       3.3.2.1.  IPv6 Provider Edge/IPv4 Provider Edge (6PE/4PE) .  11
       3.3.2.2.  IPv6 Virtual Private Extension/IPv4 Virtual
                 Private Extension (6VPE/4VPE) . . . . . . . . . .  11
       3.3.2.3.  BGP Encapsulation Subsequent Address Family
                 Identifier (SAFI) . . . . . . . . . . . . . . . .  12
       3.3.2.4.  Multicast in MPLS/BGP IP VPN (MVPN) . . . . . . .  12
     3.3.3.  MPLS Transport Profile (MPLS-TP)  . . . . . . . . . .  13
   3.4.  MPLS Operations, Administration, and Maintenance (MPLS
         OAM)  . . . . . . . . . . . . . . . . . . . . . . . . . .  13
     3.4.1.  Extended ICMP . . . . . . . . . . . . . . . . . . . .  14
     3.4.2.  Label Switched Path Ping (LSP Ping) . . . . . . . . .  15
     3.4.3.  Bidirectional Forwarding Detection (BFD)  . . . . . .  16
     3.4.4.  Pseudowire OAM  . . . . . . . . . . . . . . . . . . .  16
     3.4.5.  MPLS Transport Profile (MPLS-TP) OAM  . . . . . . . .  16
   3.5.  MIB Modules . . . . . . . . . . . . . . . . . . . . . . .  17
 4.  Gap Summary . . . . . . . . . . . . . . . . . . . . . . . . .  17
 5.  Security Considerations . . . . . . . . . . . . . . . . . . .  18
 6.  References  . . . . . . . . . . . . . . . . . . . . . . . . .  19
   6.1.  Normative References  . . . . . . . . . . . . . . . . . .  19
   6.2.  Informative References  . . . . . . . . . . . . . . . . .  20
 Acknowledgements  . . . . . . . . . . . . . . . . . . . . . . . .  26
 Contributors  . . . . . . . . . . . . . . . . . . . . . . . . . .  26
 Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .  28

George & Pignataro Informational [Page 3] RFC 7439 IPv6-Only MPLS January 2015

1. Introduction

 IPv6 [RFC2460] is an integral part of modern network deployments.  At
 the time when this document was written, the majority of these IPv6
 deployments were using dual-stack implementations, where IPv4 and
 IPv6 are supported equally on many or all of the network nodes, and
 single-stack primarily referred to IPv4-only devices.  Dual-stack
 deployments provide a useful margin for protocols and features that
 are not currently capable of operating solely over IPv6, because they
 can continue using IPv4 as necessary.  However, as IPv6 deployment
 and usage becomes more pervasive, and IPv4 exhaustion begins driving
 changes in address consumption behaviors, there is an increasing
 likelihood that many networks will need to start operating some or
 all of their network nodes either as primarily IPv6 (most functions
 use IPv6, a few legacy features use IPv4), or as IPv6-only (no IPv4
 provisioned on the device).  This transition toward IPv6-only
 operation exposes any gaps where features, protocols, or
 implementations are still reliant on IPv4 for proper function.  To
 that end, and in the spirit of the recommendation in RFC 6540
 [RFC6540] that implementations need to stop requiring IPv4 for proper
 and complete function, this document reviews the MPLS protocol suite
 in the context of IPv6 and identifies gaps that must be addressed in
 order to allow MPLS-related protocols and applications to be used
 with IPv6-only networks and networks that are primarily IPv6
 (hereafter referred to as IPv6-primary).  This document is intended
 to focus on gaps in the standards defining the MPLS suite, and not to
 highlight particular vendor implementations (or lack thereof) in the
 context of IPv6-only MPLS functionality.

2. Use Case

 This section discusses some drivers for ensuring that MPLS completely
 supports IPv6-only operation.  It is not intended to be a
 comprehensive discussion of all potential use cases, but rather a
 discussion of one use case to provide context and justification to
 undertake such a gap analysis.
 IP convergence is continuing to drive new classes of devices to begin
 communicating via IP.  Examples of such devices could include set-top
 boxes for IP video distribution, cell tower electronics (macro or
 micro cells), infrastructure Wi-Fi access points, and devices for
 machine-to-machine (M2M) or Internet of Things (IoT) applications.
 In some cases, these classes of devices represent a very large
 deployment base, on the order of thousands or even millions of
 devices network-wide.  The scale of these networks, coupled with the
 increasingly overlapping use of RFC 1918 [RFC1918] address space
 within the average network and the lack of globally routable IPv4
 space available for long-term growth, begins to drive the need for

George & Pignataro Informational [Page 4] RFC 7439 IPv6-Only MPLS January 2015

 many of the endpoints in this network to be managed solely via IPv6.
 Even if these devices are carrying some IPv4 user data, it is often
 encapsulated in another protocol such that the communication between
 the endpoint and its upstream devices can be IPv6-only without
 impacting support for IPv4 on user data.  As the number of devices to
 manage increases, the operator is compelled to move to IPv6.
 Depending on the MPLS features required, it is plausible to assume
 that the (existing) MPLS network will need to be extended to these
 IPv6-only devices.
 Additionally, as the impact of IPv4 exhaustion becomes more acute,
 more and more aggressive IPv4 address reclamation measures will be
 justified.  Many networks are likely to focus on preserving their
 remaining IPv4 addresses for revenue-generating customers so that
 legacy support for IPv4 can be maintained as long as necessary.  As a
 result, it may be appropriate for some or all of the network
 infrastructure, including MPLS Label Switching Routers (LSRs) and
 Label Edge Routers (LERs), to have its IPv4 addresses reclaimed and
 transition toward IPv6-only operation.

3. Gap Analysis

 This gap analysis aims to answer the question of what fails when one
 attempts to use MPLS features on a network of IPv6-only devices.  The
 baseline assumption for this analysis is that some endpoints, as well
 as Label Switching Routers (Provider Edge (PE) and Provider (P)
 routers), only have IPv6 transport available and need to support the
 full suite of MPLS features defined as of the time of this document's
 writing at parity with the support on an IPv4 network.  This is
 necessary whether they are enabled via the Label Distribution
 Protocol (LDP) [RFC5036], RSVP - Traffic Engineering (RSVP-TE)
 [RFC3209], or Border Gateway Protocol (BGP) [RFC3107], and whether
 they are encapsulated in MPLS [RFC3032], IP [RFC4023], Generic
 Routing Encapsulation (GRE) [RFC4023], or Layer 2 Tunneling Protocol
 Version 3 (L2TPv3) [RFC4817].  It is important when evaluating these
 gaps to distinguish between user data and control-plane data, because
 while this document is focused on IPv6-only operation, it is quite
 likely that some amount of the user payload data being carried in the
 IPv6-only MPLS network will still be IPv4.
 A note about terminology: Gaps identified by this document are
 characterized as "Major" or "Minor".  Major gaps refer to significant
 changes necessary in one or more standards to address the gap due to
 existing standards language having either missing functionality for
 IPv6-only operation or explicit language requiring the use of IPv4
 with no IPv6 alternatives defined.  Minor gaps refer to changes
 necessary primarily to clarify existing standards language.  Usually

George & Pignataro Informational [Page 5] RFC 7439 IPv6-Only MPLS January 2015

 these changes are needed in order to explicitly codify IPv6 support
 in places where it is either implicit or omitted today, but the
 omission is unlikely to prevent IPv6-only operation.

3.1. MPLS Data Plane

 MPLS labeled packets can be transmitted over a variety of data links
 [RFC3032], and MPLS labeled packets can also be encapsulated over IP.
 The encapsulations of MPLS in IP and GRE, as well as MPLS over
 L2TPv3, support IPv6.  See Section 3 of RFC 4023 [RFC4023] and
 Section 2 of RFC 4817 [RFC4817], respectively.
 Gap: None.

3.2. MPLS Control Plane

3.2.1. Label Distribution Protocol (LDP)

 The Label Distribution Protocol (LDP) [RFC5036] defines a set of
 procedures for distribution of labels between Label Switching Routers
 that can use the labels for forwarding traffic.  While LDP was
 designed to use an IPv4 or dual-stack IP network, it has a number of
 deficiencies that prevent it from working in an IPv6-only network.
 LDP-IPv6 [LDP-IPv6] highlights some of the deficiencies when LDP is
 enabled in IPv6-only or dual-stack networks and specifies appropriate
 protocol changes.  These deficiencies are related to Label Switched
 Path (LSP) mapping, LDP identifiers, LDP discovery, LDP session
 establishment, next-hop address, and LDP Time To Live (TTL) security
 [RFC5082] [RFC6720].
 Gap: Major; update to RFC 5036 in progress via [LDP-IPv6], which
 should close this gap.

3.2.2. Multipoint LDP (mLDP)

 Multipoint LDP (mLDP) is a set of extensions to LDP for setting up
 Point-to-Multipoint (P2MP) and Multipoint-to-Multipoint (MP2MP) LSPs.
 These extensions are specified in RFC 6388 [RFC6388].  In terms of
 IPv6-only gap analysis, mLDP has two identified areas of interest:
 1.  LDP Control Plane: Since mLDP uses the LDP control plane to
     discover and establish sessions with the peer, it shares the same
     gaps as LDP (Section 3.2.1) with regards to control plane
     (discovery, transport, and session establishment) in an IPv6-only
     network.

George & Pignataro Informational [Page 6] RFC 7439 IPv6-Only MPLS January 2015

 2.  Multipoint (MP) Forwarding Equivalence Class (FEC) Root Address:
     mLDP defines its own MP FECs and rules, different from LDP, to
     map MP LSPs.  An mLDP MP FEC contains a Root Address field that
     is an IP address in IP networks.  The current specification
     allows specifying the root address according to the Address
     Family Identifier (AFI), and hence covers both IPv4 or IPv6 root
     addresses, requiring no extension to support IPv6-only MP LSPs.
     The root address is used by each LSR participating in an MP LSP
     setup such that root address reachability is resolved by doing a
     table lookup against the root address to find corresponding
     upstream neighbor(s).  This will pose a problem if an MP LSP
     traverses IPv4-only and IPv6-only nodes in a dual-stack network
     on the way to the root node.
 For example, consider following setup, where R1/R6 are IPv4-only, R3/
 R4 are IPv6-only, and R2/R5 are dual-stack LSRs:
 ( IPv4-only )  (  IPv6-only   )  ( IPv4-only )
        R1 -- R2 -- R3 -- R4 -- R5 -- R6
        Leaf                          Root
 Assume R1 to be a leaf node for a P2MP LSP rooted at R6 (root node).
 R1 uses R6's IPv4 address as the root address in MP FEC.  As the MP
 LSP signaling proceeds from R1 to R6, the MP LSP setup will fail on
 the first IPv6-only transit/branch LSRs (R3) when trying to find IPv4
 root address reachability.  RFC 6512 [RFC6512] defines a recursive-
 FEC solution and procedures for mLDP when the backbone (transit/
 branch) LSRs have no route to the root.  The proposed solution is
 defined for a BGP-free core in a VPN environment, but a similar
 concept can be used/extended to solve the above issue of the
 IPv6-only backbone receiving an MP FEC element with an IPv4 address.
 The solution will require a border LSR (the one that is sitting on
 the border of an IPv4/IPv6 island (namely, R2 and R5 in this
 example)) to translate an IPv4 root address to an equivalent IPv6
 address (and vice versa) through procedures similar to RFC 6512.
 Gap: Major; update in progress for LDP via [LDP-IPv6], may need
 additional updates to RFC 6512.

3.2.3. RSVP - Traffic Engineering (RSVP-TE)

 RSVP-TE [RFC3209] defines a set of procedures and enhancements to
 establish LSP tunnels that can be automatically routed away from
 network failures, congestion, and bottlenecks.  RSVP-TE allows
 establishing an LSP for an IPv4 or IPv6 prefix, thanks to its
 LSP_TUNNEL_IPv6 object and subobjects.
 Gap: None.

George & Pignataro Informational [Page 7] RFC 7439 IPv6-Only MPLS January 2015

3.2.3.1. Interior Gateway Protocol (IGP)

 RFC 3630 [RFC3630] specifies a method of adding traffic engineering
 capabilities to OSPF Version 2.  New TLVs and sub-TLVs were added in
 RFC 5329 [RFC5329] to extend TE capabilities to IPv6 networks in OSPF
 Version 3.
 RFC 5305 [RFC5305] specifies a method of adding traffic engineering
 capabilities to IS-IS.  New TLVs and sub-TLVs were added in RFC 6119
 [RFC6119] to extend TE capabilities to IPv6 networks.
 Gap: None.

3.2.3.2. RSVP-TE Point-to-Multipoint (P2MP)

 RFC 4875 [RFC4875] describes extensions to RSVP-TE for the setup of
 Point-to-Multipoint (P2MP) LSPs in MPLS and Generalized MPLS (GMPLS)
 with support for both IPv4 and IPv6.
 Gap: None.

3.2.3.3. RSVP-TE Fast Reroute (FRR)

 RFC 4090 [RFC4090] specifies Fast Reroute (FRR) mechanisms to
 establish backup LSP tunnels for local repair supporting both IPv4
 and IPv6 networks.  Further, [RFC5286] describes the use of loop-free
 alternates to provide local protection for unicast traffic in pure IP
 and MPLS networks in the event of a single failure, whether link,
 node, or shared risk link group (SRLG) for both IPv4 and IPv6.
 Gap: None.

3.2.4. Path Computation Element (PCE)

 The Path Computation Element (PCE) defined in RFC 4655 [RFC4655] is
 an entity that is capable of computing a network path or route based
 on a network graph and applying computational constraints.  A Path
 Computation Client (PCC) may make requests to a PCE for paths to be
 computed.  The PCE Communication Protocol (PCEP) is designed as a
 communication protocol between PCCs and PCEs for path computations
 and is defined in RFC 5440 [RFC5440].
 The PCEP specification [RFC5440] is defined for both IPv4 and IPv6
 with support for PCE discovery via an IGP (OSPF [RFC5088] or IS-IS
 [RFC5089]) using both IPv4 and IPv6 addresses.  Note that PCEP uses
 identical encoding of subobjects, as in RSVP-TE defined in RFC 3209
 [RFC3209] that supports both IPv4 and IPv6.

George & Pignataro Informational [Page 8] RFC 7439 IPv6-Only MPLS January 2015

 The extensions to PCEP to support confidentiality [RFC5520], route
 exclusions [RFC5521], monitoring [RFC5886], and P2MP TE LSPs
 [RFC6006] have support for both IPv4 and IPv6.
 Gap: None.

3.2.5. Border Gateway Protocol (BGP)

 RFC 3107 [RFC3107] specifies a set of BGP protocol procedures for
 distributing the labels (for prefixes corresponding to any address
 family) between label switch routers so that they can use the labels
 for forwarding the traffic.  RFC 3107 allows BGP to distribute the
 label for IPv4 or IPv6 prefix in an IPv6-only network.
 Gap: None.

3.2.6. Generalized Multi-Protocol Label Switching (GMPLS)

 The Generalized Multi-Protocol Label Switching (GMPLS) specification
 includes signaling functional extensions [RFC3471] and RSVP-TE
 extensions [RFC3473].  The gap analysis in Section 3.2.3 applies to
 these.
 RFC 4558 [RFC4558] specifies Node-ID Based RSVP Hello Messages with
 capability for both IPv4 and IPv6.  RFC 4990 [RFC4990] clarifies the
 use of IPv6 addresses in GMPLS networks including handling in the MIB
 modules.
 The second paragraph of Section 5.3 of RFC 6370 [RFC6370] describes
 the mapping from an MPLS Transport Profile (MPLS-TP) LSP_ID to RSVP-
 TE with an assumption that Node_IDs are derived from valid IPv4
 addresses.  This assumption fails in an IPv6-only network, given that
 there would not be any IPv4 addresses.
 Gap: Minor; Section 5.3 of RFC 6370 [RFC6370] needs to be updated.

3.3. MPLS Applications

3.3.1. Layer 2 Virtual Private Network (L2VPN)

 L2VPN [RFC4664] specifies two fundamentally different kinds of Layer
 2 VPN services that a service provider could offer to a customer:
 Virtual Private Wire Service (VPWS) and Virtual Private LAN Service
 (VPLS).  RFC 4447 [RFC4447] and RFC 4762 [RFC4762] specify the LDP
 protocol changes to instantiate VPWS and VPLS services, respectively,
 in an MPLS network using LDP as the signaling protocol.  This is
 complemented by RFC 6074 [RFC6074], which specifies a set of
 procedures for instantiating L2VPNs (e.g., VPWS, VPLS) using BGP as a

George & Pignataro Informational [Page 9] RFC 7439 IPv6-Only MPLS January 2015

 discovery protocol and LDP, as well as L2TPv3, as a signaling
 protocol.  RFC 4761 [RFC4761] and RFC 6624 [RFC6624] specify BGP
 protocol changes to instantiate VPLS and VPWS services in an MPLS
 network, using BGP for both discovery and signaling.
 In an IPv6-only MPLS network, use of L2VPN represents a connection of
 Layer 2 islands over an IPv6 MPLS core, and very few changes are
 necessary to support operation over an IPv6-only network.  The L2VPN
 signaling protocol is either BGP or LDP in an MPLS network, and both
 can run directly over IPv6 core infrastructure as well as IPv6 edge
 devices.  RFC 6074 [RFC6074] is the only RFC that appears to have a
 gap for IPv6-only operation.  In its discovery procedures (Sections
 3.2.2 and 6 of RFC 6074 [RFC6074]), it suggests encoding PE IP
 addresses in the Virtual Switching Instance ID (VSI-ID), which is
 encoded in Network Layer Reachability Information (NLRI) and should
 not exceed 12 bytes (to differentiate its AFI/SAFI (Subsequent
 Address Family Identifier) encoding from RFC 4761).  This means that
 a PE IP address cannot be an IPv6 address.  Also, in its signaling
 procedures (Section 3.2.3 of RFC 6074 [RFC6074]), it suggests
 encoding PE_addr in the Source Attachment Individual Identifier
 (SAII) and the Target Attachment Individual Identifier (TAII), which
 are limited to 32 bits (AII Type=1) at the moment.
 RFC 6073 [RFC6073] defines the new LDP Pseudowire (PW) Switching
 Point PE TLV, which supports IPv4 and IPv6.
 Gap: Minor; RFC 6074 needs to be updated.

3.3.1.1. Ethernet VPN (EVPN)

 Ethernet VPN [EVPN] defines a method for using BGP MPLS-based
 Ethernet VPNs.  Because it can use functions in LDP and mLDP, as well
 as Multicast VPLS [RFC7117], it inherits LDP gaps previously
 identified in Section 3.2.1.  Once those gaps are resolved, it should
 function properly on IPv6-only networks as defined.
 Gap: Major for LDP; update to RFC 5036 in progress via [LDP-IPv6]
 that should close this gap (see Section 3.2.1).

3.3.2. Layer 3 Virtual Private Network (L3VPN)

 RFC 4364 [RFC4364] defines a method by which a Service Provider may
 use an IP backbone to provide IP VPNs for its customers.  The
 following use cases arise in the context of this gap analysis:
 1.  Connecting IPv6 islands over IPv6-only MPLS network
 2.  Connecting IPv4 islands over IPv6-only MPLS network

George & Pignataro Informational [Page 10] RFC 7439 IPv6-Only MPLS January 2015

 Both use cases require mapping an IP packet to an IPv6-signaled LSP.
 RFC 4364 defines Layer 3 Virtual Private Networks (L3VPNs) for
 IPv4-only and has references to 32-bit BGP next-hop addresses.  RFC
 4659 [RFC4659] adds support for IPv6 on L3VPNs, including 128-bit BGP
 next-hop addresses, and discusses operation whether IPv6 is the
 payload or the underlying transport address family.  However, RFC
 4659 does not formally update RFC 4364, and thus an implementer may
 miss this additional set of standards unless it is explicitly
 identified independently of the base functionality defined in RFC
 4364.  Further, Section 1 of RFC 4659 explicitly identifies use case
 2 as out of scope for the document.
 The authors do not believe that there are any additional issues
 encountered when using L2TPv3, RSVP, or GRE (instead of MPLS) as
 transport on an IPv6-only network.
 Gap: Major; RFC 4659 needs to be updated to explicitly cover use case
 2 (discussed in further detail below)

3.3.2.1. IPv6 Provider Edge/IPv4 Provider Edge (6PE/4PE)

 RFC 4798 [RFC4798] defines IPv6 Provider Edge (6PE), which defines
 how to interconnect IPv6 islands over a MPLS-enabled IPv4 cloud.
 However, use case 2 is doing the opposite, and thus could also be
 referred to as IPv4 Provider Edge (4PE).  The method to support this
 use case is not defined explicitly.  To support it, IPv4 edge devices
 need to be able to map IPv4 traffic to MPLS IPv6 core LSPs.  Also,
 the core switches may not understand IPv4 at all, but in some cases
 they may need to be able to exchange Labeled IPv4 routes from one
 Autonomous System (AS) to a neighboring AS.
 Gap: Major; RFC 4798 covers only the "6PE" case.  Use case 2 is
 currently not specified in an RFC.

3.3.2.2. IPv6 Virtual Private Extension/IPv4 Virtual Private Extension

        (6VPE/4VPE)
 RFC 4659 [RFC4659] defines IPv6 Virtual Private Network Extension
 (6VPE), a method by which a Service Provider may use its packet-
 switched backbone to provide Virtual Private Network (VPN) services
 for its IPv6 customers.  It allows the core network to be MPLS IPv4
 or MPLS IPv6, thus addressing use case 1 above.  RFC 4364 should work
 as defined for use case 2 above, which could also be referred to as
 IPv4 Virtual Private Extension (4VPE), but the RFC explicitly does
 not discuss this use and defines it as out of scope.
 Gap: Minor; RFC 4659 needs to be updated to explicitly cover use case
 2.

George & Pignataro Informational [Page 11] RFC 7439 IPv6-Only MPLS January 2015

3.3.2.3. BGP Encapsulation Subsequent Address Family Identifier (SAFI)

 RFC 5512 [RFC5512] defines the BGP Encapsulation SAFI and the BGP
 Tunnel Encapsulation Attribute, which can be used to signal tunneling
 over an IP Core that is using a single address family.  This
 mechanism supports transport of MPLS (and other protocols) over
 Tunnels in an IP core (including an IPv6-only core).  In this
 context, load balancing can be provided as specified in RFC 5640
 [RFC5640].
 Gap: None.

3.3.2.4. Multicast in MPLS/BGP IP VPN (MVPN)

 RFC 6513 [RFC6513] defines the procedure to provide multicast service
 over an MPLS VPN backbone for downstream customers.  It is sometimes
 referred to as Next Generation Multicast VPN (NG-MVPN) The procedure
 involves the below set of protocols.

3.3.2.4.1. PE-CE Multicast Routing Protocol

 RFC 6513 [RFC6513] explains the use of Protocol Independent Multicast
 (PIM) as a Provider Edge - Customer Edge (PE-CE) protocol, while
 Section 11.1.2 of RFC 6514 [RFC6514] explains the use of mLDP as a
 PE-CE protocol.
 The MCAST-VPN NLRI route-type format defined in RFC 6514 [RFC6514] is
 not sufficiently covering all scenarios when mLDP is used as a PE-CE
 protocol.  The issue is explained in Section 2 of [mLDP-NLRI] along
 with a new route type that encodes the mLDP FEC in NLRI.
 Further, [PE-CE] defines the use of BGP as a PE-CE protocol.
 Gap: None.

3.3.2.4.2. P-Tunnel Instantiation

 [RFC6513] explains the use of the below tunnels:
 o  RSVP-TE P2MP LSP
 o  PIM Tree
 o  mLDP P2MP LSP
 o  mLDP MP2MP LSP
 o  Ingress Replication

George & Pignataro Informational [Page 12] RFC 7439 IPv6-Only MPLS January 2015

 Gap: Gaps in RSVP-TE P2MP LSP (Section 3.2.3.2) and mLDP
 (Section 3.2.2) P2MP and MP2MP LSP are covered in previous sections.
 There are no MPLS-specific gaps for PIM Tree or Ingress Replication,
 and any protocol-specific gaps not related to MPLS are outside the
 scope of this document.

3.3.2.4.3. PE-PE Multicast Routing Protocol

 Section 3.1 of RFC 6513 [RFC6513] explains the use of PIM as a PE-PE
 protocol, while RFC 6514 [RFC6514] explains the use of BGP as a PE-PE
 protocol.
 PE-PE multicast routing is not specific to P-tunnels or to MPLS.  It
 can be PIM or BGP with P-tunnels that are label based or PIM tree
 based.  Enabling PIM as a PE-PE multicast protocol is equivalent to
 running it on a non-MPLS IPv6 network, so there are not any MPLS-
 specific considerations and any gaps are applicable for non-MPLS
 networks as well.  Similarly, BGP only includes the P-Multicast
 Service Interface (PMSI) tunnel attribute as a part of the NLRI,
 which is inherited from P-tunnel instantiation and considered to be
 an opaque value.  Any gaps in the control plane (PIM or BGP) will not
 be specific to MPLS.
 Gap: Any gaps in PIM or BGP as a PE-PE multicast routing protocol are
 not unique to MPLS, and therefore are outside the scope of this
 document.  It is included for completeness.

3.3.3. MPLS Transport Profile (MPLS-TP)

 MPLS-TP does not require IP (see Section 2 of RFC 5921 [RFC5921]) and
 should not be affected by operation on an IPv6-only network.
 Therefore, this is considered out of scope for this document but is
 included for completeness.
 Although not required, MPLS-TP can use IP.  One such example is
 included in Section 3.2.6, where MPLS-TP identifiers can be derived
 from valid IPv4 addresses.
 Gap: None.  MPLS-TP does not require IP.

3.4. MPLS Operations, Administration, and Maintenance (MPLS OAM)

 For MPLS LSPs, there are primarily three OAM mechanisms: Extended
 ICMP [RFC4884] [RFC4950], LSP Ping [RFC4379], and Bidirectional
 Forwarding Detection (BFD) for MPLS LSPs [RFC5884].  For MPLS
 Pseudowires, there is also Virtual Circuit Connectivity Verification
 (VCCV) [RFC5085] [RFC5885].  Most of these mechanisms work in pure

George & Pignataro Informational [Page 13] RFC 7439 IPv6-Only MPLS January 2015

 IPv6 environments, but there are some problems encountered in mixed
 environments due to address-family mismatches.  The next subsections
 cover these gaps in detail.
 Gap: Major; RFC 4379 needs to be updated to better support multipath
 IPv6.  Additionally, there is potential for dropped messages in
 Extended ICMP and LSP Ping due to IP version mismatches.  It is
 important to note that this is a more generic problem with tunneling
 when address-family mismatches exist and is not specific to MPLS.
 While MPLS will be affected, it will be difficult to fix this problem
 specifically for MPLS, rather than fixing the more generic problem.

3.4.1. Extended ICMP

 Extended ICMP to support Multi-part messages is defined in RFC 4884
 [RFC4884].  This extensibility is defined generally for both ICMPv4
 and ICMPv6.  The specific ICMP extensions for MPLS are defined in RFC
 4950 [RFC4950].  ICMP Multi-part with MPLS extensions works for IPv4
 and IPv6.  However, the mechanisms described in RFC 4884 and 4950 may
 fail when tunneling IPv4 traffic over an LSP that is supported by an
 IPv6-only infrastructure.
 Assume the following:
 o  The path between two IPv4-only hosts contains an MPLS LSP.
 o  The two routers that terminate the LSP run dual stack.
 o  The LSP interior routers run IPv6 only.
 o  The LSP is signaled over IPv6.
 Now assume that one of the hosts sends an IPv4 packet to the other.
 However, the packet's TTL expires on an LSP interior router.
 According to RFC 3032 [RFC3032], the interior router should examine
 the IPv4 payload, format an ICMPv4 message, and send it (over the
 tunnel upon which the original packet arrived) to the egress LSP.  In
 this case, however, the LSP interior router is not IPv4-aware.  It
 cannot parse the original IPv4 datagram, nor can it send an IPv4
 message.  So, no ICMP message is delivered to the source.  Some
 specific ICMP extensions, in particular, ICMP extensions for
 interface and next-hop identification [RFC5837], restrict the address
 family of address information included in an Interface Information
 Object to the same one as the ICMP (see Section 4.5 of RFC 5837).
 While these extensions are not MPLS specific, they can be used with
 MPLS packets carrying IP datagrams.  This has no implications for
 IPv6-only environments.

George & Pignataro Informational [Page 14] RFC 7439 IPv6-Only MPLS January 2015

 Gap: Major; IP version mismatches may cause dropped messages.
 However, as noted in the previous section, this problem is not
 specific to MPLS.

3.4.2. Label Switched Path Ping (LSP Ping)

 The LSP Ping mechanism defined in RFC 4379 [RFC4379] is specified to
 work with IPv6.  Specifically, the Target FEC Stacks include both
 IPv4 and IPv6 versions of all FECs (see Section 3.2 of RFC 4379).
 The only exceptions are the Pseudowire FECs, which are later
 specified for IPv6 in RFC 6829 [RFC6829].  The multipath information
 also includes IPv6 encodings (see Section 3.3.1 of RFC 4379).
 LSP Ping packets are UDP packets over either IPv4 or IPv6 (see
 Section 4.3 of RFC 4379).  However, for IPv6 the destination IP
 address is a (randomly chosen) IPv6 address from the range
 0:0:0:0:0:FFFF:127/104; that is, using an IPv4-mapped IPv6 address.
 This is a transitional mechanism that should not bleed into IPv6-only
 networks, as [IPv4-MAPPED] explains.  The issue is that the MPLS LSP
 Ping mechanism needs a range of loopback IP addresses to be used as
 destination addresses to exercise Equal Cost Multiple Path (ECMP),
 but the IPv6 address architecture specifies a single address
 (::1/128) for loopback.  A mechanism to achieve this was proposed in
 [LOOPBACK-PREFIX].
 Additionally, RFC 4379 does not define the value to be used in the
 IPv6 Router Alert option (RAO).  For IPv4 RAO, a value of zero is
 used.  However, there is no equivalent value for IPv6 RAO.  This gap
 needs to be fixed to be able to use LSP Ping in IPv6 networks.
 Further details on this gap are captured, along with a proposed
 solution, in [IPv6-RAO].
 Another gap is that the mechanisms described in RFC 4379 may fail
 when tunneling IPv4 traffic over an LSP that is supported by
 IPv6-only infrastructure.
 Assume the following:
 o  LSP Ping is operating in traceroute mode over an MPLS LSP.
 o  The two routers that terminate the LSP run dual stack.
 o  The LSP interior routers run IPv6 only.
 o  The LSP is signaled over IPv6.

George & Pignataro Informational [Page 15] RFC 7439 IPv6-Only MPLS January 2015

 Packets will expire at LSP interior routers.  According to RFC 4379,
 the interior router must parse the IPv4 Echo Request and then send an
 IPv4 Echo Reply.  However, the LSP interior router is not IPv4-aware.
 It cannot parse the IPv4 Echo Request, nor can it send an IPv4 Echo
 Reply.  So, no reply is sent.
 The mechanism described in RFC 4379 also does not sufficiently
 explain the behavior in certain IPv6-specific scenarios.  For
 example, RFC 4379 defines the K value as 28 octets when the Address
 Family is set to IPv6 Unnumbered, but it doesn't describe how to
 carry a 32-bit LSR Router ID in the 128-bit Downstream IP Address
 field.
 Gap: Major; LSP Ping uses IPv4-mapped IPv6 addresses.  IP version
 mismatches may cause dropped messages and unclear mapping from the
 LSR Router ID to Downstream IP Address.

3.4.3. Bidirectional Forwarding Detection (BFD)

 The BFD specification for MPLS LSPs [RFC5884] is defined for IPv4, as
 well as IPv6, versions of MPLS FECs (see Section 3.1 of RFC 5884).
 Additionally, the BFD packet is encapsulated over UDP and specified
 to run over both IPv4 and IPv6 (see Section 7 of RFC 5884).
 Gap: None.

3.4.4. Pseudowire OAM

 The OAM specifications for MPLS Pseudowires define usage for both
 IPv4 and IPv6.  Specifically, VCCV [RFC5085] can carry IPv4 or IPv6
 OAM packets (see Sections 5.1.1 and 5.2.1 of RFC 5085), and VCCV for
 BFD [RFC5885] also defines an IPv6 encapsulation (see Section 3.2 of
 RFC 5885).
 Additionally, for LSP Ping for pseudowires, the Pseudowire FECs are
 specified for IPv6 in RFC 6829 [RFC6829].
 Gap: None.

3.4.5. MPLS Transport Profile (MPLS-TP) OAM

 As with MPLS-TP, MPLS-TP OAM [RFC6371] does not require IP or
 existing MPLS OAM functions and should not be affected by operation
 on an IPv6-only network.  Therefore, this is out of scope for this
 document but is included for completeness.  Although not required,
 MPLS-TP can use IP.
 Gap: None.  MPLS-TP OAM does not require IP.

George & Pignataro Informational [Page 16] RFC 7439 IPv6-Only MPLS January 2015

3.5. MIB Modules

 RFC 3811 [RFC3811] defines the textual conventions for MPLS.  These
 lack support for IPv6 in defining MplsExtendedTunnelId and
 MplsLsrIdentifier.  These textual conventions are used in the MPLS-TE
 MIB specification [RFC3812], the GMPLS-TE MIB specification [RFC4802]
 and the FRR extension [RFC6445].  "Definitions of Textual Conventions
 (TCs) for Multiprotocol Label Switching (MPLS) Management" [MPLS-TC]
 tries to resolve this gap by marking this textual convention as
 obsolete.
 The other MIB specifications for LSR [RFC3813], LDP [RFC3815], and TE
 [RFC4220] have support for both IPv4 and IPv6.
 Lastly, RFC 4990 [RFC4990] discusses how to handle IPv6 sources and
 destinations in the MPLS and GMPLS-TE MIB modules.  In particular,
 Section 8 of RFC 4990 [RFC4990] describes a method of defining or
 monitoring an LSP tunnel using the MPLS-TE and GMPLS-TE MIB modules,
 working around some of the limitations in RFC 3811 [RFC3811].
 Gap: Minor; Section 8 of RFC 4990 [RFC4990] describes a method to
 handle IPv6 addresses in the MPLS-TE [RFC3812] and GMPLS-TE [RFC4802]
 MIB modules.  Work underway to update RFC 3811 via [MPLS-TC], may
 also need to update RFC 3812, RFC 4802, and RFC 6445, which depend on
 it.

4. Gap Summary

 This document has reviewed a wide variety of MPLS features and
 protocols to determine their suitability for use on IPv6-only or
 IPv6-primary networks.  While some parts of the MPLS suite will
 function properly without additional changes, gaps have been
 identified in others that will need to be addressed with follow-on
 work.  This section will summarize those gaps, along with pointers to
 any work in progress to address them.  Note that because the
 referenced documents are works in progress and do not have consensus
 at the time of this document's publication, there could be other
 solutions proposed at a future time, and the pointers in this
 document should not be considered normative in any way.
 Additionally, work in progress on new features that use MPLS
 protocols will need to ensure that those protocols support operation
 on IPv6-only or IPv6-primary networks, or explicitly identify any
 dependencies on existing gaps that, once resolved, will allow proper
 IPv6-only operation.

George & Pignataro Informational [Page 17] RFC 7439 IPv6-Only MPLS January 2015

            Identified Gaps in MPLS for IPv6-Only Networks
 +---------+---------------------------------------+-----------------+
 |   Item  |                  Gap                  |   Addressed in  |
 +---------+---------------------------------------+-----------------+
 |   LDP   |   LSP mapping, LDP identifiers, LDP   |    [LDP-IPv6]   |
 | S.3.2.1 | discovery, LDP session establishment, |                 |
 |         |     next-hop address, and LDP TTL     |                 |
 |         |                security               |                 |
 +---------+---------------------------------------+-----------------+
 |   mLDP  |    Inherits gaps from LDP, RFC 6512   |     Inherits    |
 | S.3.2.2 |               [RFC6512]               |   [LDP-IPv6],   |
 |         |                                       |    additional   |
 |         |                                       |    fixes TBD    |
 +---------+---------------------------------------+-----------------+
 |  GMPLS  | RFC 6370 [RFC6370] Node ID derivation |       TBD       |
 | S.3.2.6 |                                       |                 |
 +---------+---------------------------------------+-----------------+
 |  L2VPN  |     RFC 6074 [RFC6074] discovery,     |       TBD       |
 | S.3.3.1 |               signaling               |                 |
 +---------+---------------------------------------+-----------------+
 |  L3VPN  |  RFC 4659 [RFC4659] does not define a |       TBD       |
 | S.3.3.2 |          method for 4PE/4VPE          |                 |
 +---------+---------------------------------------+-----------------+
 |   OAM   |  RFC 4379 [RFC4379] No IPv6 multipath |    [IPv6-RAO]   |
 |  S.3.4  |     support, no IPv6 RAO, possible    |                 |
 |         |     dropped messages in IP version    |                 |
 |         |                mismatch               |                 |
 +---------+---------------------------------------+-----------------+
 |   MIB   |   RFC 3811 [RFC3811] no IPv6 textual  |    [MPLS-TC]    |
 | Modules |               convention              |                 |
 |  S.3.5  |                                       |                 |
 +---------+---------------------------------------+-----------------+
                     Table 1: IPv6-Only MPLS Gaps

5. Security Considerations

 Changing the address family used for MPLS network operation does not
 fundamentally alter the security considerations currently extant in
 any of the specifics of the protocol or its features.  However,
 follow-on work recommended by this gap analysis will need to address
 any effects that the use of IPv6 in their modifications may have on
 security.

George & Pignataro Informational [Page 18] RFC 7439 IPv6-Only MPLS January 2015

6. References

6.1. Normative References

 [RFC2460]  Deering, S. and R. Hinden, "Internet Protocol, Version 6
            (IPv6) Specification", RFC 2460, December 1998,
            <http://www.rfc-editor.org/info/rfc2460>.
 [RFC3032]  Rosen, E., Tappan, D., Fedorkow, G., Rekhter, Y.,
            Farinacci, D., Li, T., and A. Conta, "MPLS Label Stack
            Encoding", RFC 3032, January 2001,
            <http://www.rfc-editor.org/info/rfc3032>.
 [RFC3107]  Rekhter, Y. and E. Rosen, "Carrying Label Information in
            BGP-4", RFC 3107, May 2001,
            <http://www.rfc-editor.org/info/rfc3107>.
 [RFC3209]  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,
            <http://www.rfc-editor.org/info/rfc3209>.
 [RFC3471]  Berger, L., "Generalized Multi-Protocol Label Switching
            (GMPLS) Signaling Functional Description", RFC 3471,
            January 2003, <http://www.rfc-editor.org/info/rfc3471>.
 [RFC3473]  Berger, L., "Generalized Multi-Protocol Label Switching
            (GMPLS) Signaling Resource ReserVation Protocol-Traffic
            Engineering (RSVP-TE) Extensions", RFC 3473, January 2003,
            <http://www.rfc-editor.org/info/rfc3473>.
 [RFC3811]  Nadeau, T. and J. Cucchiara, "Definitions of Textual
            Conventions (TCs) for Multiprotocol Label Switching (MPLS)
            Management", RFC 3811, June 2004,
            <http://www.rfc-editor.org/info/rfc3811>.
 [RFC4023]  Worster, T., Rekhter, Y., and E. Rosen, "Encapsulating
            MPLS in IP or Generic Routing Encapsulation (GRE)", RFC
            4023, March 2005,
            <http://www.rfc-editor.org/info/rfc4023>.
 [RFC4379]  Kompella, K. and G. Swallow, "Detecting Multi-Protocol
            Label Switched (MPLS) Data Plane Failures", RFC 4379,
            February 2006, <http://www.rfc-editor.org/info/rfc4379>.

George & Pignataro Informational [Page 19] RFC 7439 IPv6-Only MPLS January 2015

 [RFC4659]  De Clercq, J., Ooms, D., Carugi, M., and F. Le Faucheur,
            "BGP-MPLS IP Virtual Private Network (VPN) Extension for
            IPv6 VPN", RFC 4659, September 2006,
            <http://www.rfc-editor.org/info/4659>.
 [RFC4817]  Townsley, M., Pignataro, C., Wainner, S., Seely, T., and
            J. Young, "Encapsulation of MPLS over Layer 2 Tunneling
            Protocol Version 3", RFC 4817, March 2007,
            <http://www.rfc-editor.org/info/rfc4817>.
 [RFC5036]  Andersson, L., Minei, I., and B. Thomas, "LDP
            Specification", RFC 5036, October 2007,
            <http://www.rfc-editor.org/info/rfc5036>.
 [RFC6074]  Rosen, E., Davie, B., Radoaca, V., and W. Luo,
            "Provisioning, Auto-Discovery, and Signaling in Layer 2
            Virtual Private Networks (L2VPNs)", RFC 6074, January
            2011, <http://www.rfc-editor.org/info/rfc6074>.
 [RFC6370]  Bocci, M., Swallow, G., and E. Gray, "MPLS Transport
            Profile (MPLS-TP) Identifiers", RFC 6370, September 2011,
            <http://www.rfc-editor.org/info/rfc6370>.
 [RFC6512]  Wijnands, IJ., Rosen, E., Napierala, M., and N. Leymann,
            "Using Multipoint LDP When the Backbone Has No Route to
            the Root", RFC 6512, February 2012,
            <http://www.rfc-editor.org/info/rfc6512>.

6.2. Informative References

 [EVPN]     Sajassi, A., Aggarwal, R., Bitar, N., Isaac, A., and J.
            Uttaro, "BGP MPLS Based Ethernet VPN", Work in Progress,
            draft-ietf-l2vpn-evpn-11, October 2014.
 [IPv4-MAPPED]
            Metz, C. and J. Hagino, "IPv4-Mapped Addresses on the Wire
            Considered Harmful", Work in Progress, draft-itojun-v6ops-
            v4mapped-harmful-02, October 2003.
 [IPv6-RAO]
            Raza, K., Akiya, N., and C. Pignataro, "IPv6 Router Alert
            Option for MPLS OAM", Work in Progress, draft-raza-mpls-
            oam-ipv6-rao-02, September 2014.
 [LDP-IPv6]
            Asati, R., Manral, V., Papneja, R., and C. Pignataro,
            "Updates to LDP for IPv6", Work in Progress, draft-ietf-
            mpls-ldp-ipv6-14, October 2014.

George & Pignataro Informational [Page 20] RFC 7439 IPv6-Only MPLS January 2015

 [LOOPBACK-PREFIX]
            Smith, M., "A Larger Loopback Prefix for IPv6", Work in
            Progress, draft-smith-v6ops-larger-ipv6-loopback-prefix-
            04, February 2013.
 [mLDP-NLRI]
            Wijnands, I., Rosen, E., and U. Joorde, "Encoding mLDP
            FECs in the NLRI of BGP MCAST-VPN Routes", Work in
            Progress, draft-ietf-l3vpn-mvpn-mldp-nlri-10, November
            2014.
 [MPLS-TC]  Manral, V., Tsou, T., Will, W., and F. Fondelli,
            "Definitions of Textual Conventions (TCs) for
            Multiprotocol Label Switching (MPLS) Management", Work in
            Progress, draft-manral-mpls-rfc3811bis-04, September 2014.
 [PE-CE]    Patel, K., Rekhter, Y., and E. Rosen, "BGP as an MVPN
            PE-CE Protocol", Work in Progress,
            draft-ietf-l3vpn-mvpn-pe- ce-02, October 2014.
 [RFC1918]  Rekhter, Y., Moskowitz, R., Karrenberg, D., Groot, G., and
            E. Lear, "Address Allocation for Private Internets",
            BCP 5, RFC 1918, February 1996,
            <http://www.rfc-editor.org/info/rfc1918>.
 [RFC3630]  Katz, D., Kompella, K., and D. Yeung, "Traffic Engineering
            (TE) Extensions to OSPF Version 2", RFC 3630, September
            2003, <http://www.rfc-editor.org/info/rfc3630>.
 [RFC3812]  Srinivasan, C., Viswanathan, A., and T. Nadeau,
            "Multiprotocol Label Switching (MPLS) Traffic Engineering
            (TE) Management Information Base (MIB)", RFC 3812, June
            2004, <http://www.rfc-editor.org/info/rfc3812>.
 [RFC3813]  Srinivasan, C., Viswanathan, A., and T. Nadeau,
            "Multiprotocol Label Switching (MPLS) Label Switching
            Router (LSR) Management Information Base (MIB)", RFC 3813,
            June 2004, <http://www.rfc-editor.org/info/rfc3813>.
 [RFC3815]  Cucchiara, J., Sjostrand, H., and J. Luciani, "Definitions
            of Managed Objects for the Multiprotocol Label Switching
            (MPLS), Label Distribution Protocol (LDP)", RFC 3815, June
            2004, <http://www.rfc-editor.org/info/rfc3815>.
 [RFC4090]  Pan, P., Swallow, G., and A. Atlas, "Fast Reroute
            Extensions to RSVP-TE for LSP Tunnels", RFC 4090, May
            2005, <http://www.rfc-editor.org/info/rfc4090>.

George & Pignataro Informational [Page 21] RFC 7439 IPv6-Only MPLS January 2015

 [RFC4220]  Dubuc, M., Nadeau, T., and J. Lang, "Traffic Engineering
            Link Management Information Base", RFC 4220, November
            2005, <http://www.rfc-editor.org/info/rfc4220>.
 [RFC4364]  Rosen, E. and Y. Rekhter, "BGP/MPLS IP Virtual Private
            Networks (VPNs)", RFC 4364, February 2006,
            <http://www.rfc-editor.org/info/rfc4364>.
 [RFC4447]  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,
            <http://www.rfc-editor.org/info/rfc4447>.
 [RFC4558]  Ali, Z., Rahman, R., Prairie, D., and D. Papadimitriou,
            "Node-ID Based Resource Reservation Protocol (RSVP) Hello:
            A Clarification Statement", RFC 4558, June 2006,
            <http://www.rfc-editor.org/info/rfc4558>.
 [RFC4655]  Farrel, A., Vasseur, J., and J. Ash, "A Path Computation
            Element (PCE)-Based Architecture", RFC 4655, August 2006,
            <http://www.rfc-editor.org/info/rfc4655>.
 [RFC4664]  Andersson, L. and E. Rosen, "Framework for Layer 2 Virtual
            Private Networks (L2VPNs)", RFC 4664, September 2006,
            <http://www.rfc-editor.org/info/rfc4664>.
 [RFC4761]  Kompella, K. and Y. Rekhter, "Virtual Private LAN Service
            (VPLS) Using BGP for Auto-Discovery and Signaling", RFC
            4761, January 2007,
            <http://www.rfc-editor.org/info/rfc4761>.
 [RFC4762]  Lasserre, M. and V. Kompella, "Virtual Private LAN Service
            (VPLS) Using Label Distribution Protocol (LDP) Signaling",
            RFC 4762, January 2007,
            <http://www.rfc-editor.org/info/rfc4762>.
 [RFC4798]  De Clercq, J., Ooms, D., Prevost, S., and F. Le Faucheur,
            "Connecting IPv6 Islands over IPv4 MPLS Using IPv6
            Provider Edge Routers (6PE)", RFC 4798, February 2007,
            <http://www.rfc-editor.org/info/rfc4798>.
 [RFC4802]  Nadeau, T. and A. Farrel, "Generalized Multiprotocol Label
            Switching (GMPLS) Traffic Engineering Management
            Information Base", RFC 4802, February 2007,
            <http://www.rfc-editor.org/info/rfc4802>.

George & Pignataro Informational [Page 22] RFC 7439 IPv6-Only MPLS January 2015

 [RFC4875]  Aggarwal, R., Papadimitriou, D., and S. Yasukawa,
            "Extensions to Resource Reservation Protocol - Traffic
            Engineering (RSVP-TE) for Point-to-Multipoint TE Label
            Switched Paths (LSPs)", RFC 4875, May 2007,
            <http://www.rfc-editor.org/info/rfc4875>.
 [RFC4884]  Bonica, R., Gan, D., Tappan, D., and C. Pignataro,
            "Extended ICMP to Support Multi-Part Messages", RFC 4884,
            April 2007, <http://www.rfc-editor.org/info/rfc4884>.
 [RFC4950]  Bonica, R., Gan, D., Tappan, D., and C. Pignataro, "ICMP
            Extensions for Multiprotocol Label Switching", RFC 4950,
            August 2007, <http://www.rfc-editor.org/info/rfc4950>.
 [RFC4990]  Shiomoto, K., Papneja, R., and R. Rabbat, "Use of
            Addresses in Generalized Multiprotocol Label Switching
            (GMPLS) Networks", RFC 4990, September 2007,
            <http://www.rfc-editor.org/info/rfc4990>.
 [RFC5082]  Gill, V., Heasley, J., Meyer, D., Savola, P., and C.
            Pignataro, "The Generalized TTL Security Mechanism
            (GTSM)", RFC 5082, October 2007,
            <http://www.rfc-editor.org/info/rfc5082>.
 [RFC5085]  Nadeau, T. and C. Pignataro, "Pseudowire Virtual Circuit
            Connectivity Verification (VCCV): A Control Channel for
            Pseudowires", RFC 5085, December 2007,
            <http://www.rfc-editor.org/info/rfc5085>.
 [RFC5088]  Le Roux, JL., Vasseur, JP., Ikejiri, Y., and R. Zhang,
            "OSPF Protocol Extensions for Path Computation Element
            (PCE) Discovery", RFC 5088, January 2008,
            <http://www.rfc-editor.org/info/rfc5088>.
 [RFC5089]  Le Roux, JL., Vasseur, JP., Ikejiri, Y., and R. Zhang,
            "IS-IS Protocol Extensions for Path Computation Element
            (PCE) Discovery", RFC 5089, January 2008,
            <http://www.rfc-editor.org/info/rfc5089>.
 [RFC5286]  Atlas, A. and A. Zinin, "Basic Specification for IP Fast
            Reroute: Loop-Free Alternates", RFC 5286, September 2008,
            <http://www.rfc-editor.org/info/rfc5286>.
 [RFC5305]  Li, T. and H. Smit, "IS-IS Extensions for Traffic
            Engineering", RFC 5305, October 2008,
            <http://www.rfc-editor.org/info/rfc5305>.

George & Pignataro Informational [Page 23] RFC 7439 IPv6-Only MPLS January 2015

 [RFC5329]  Ishiguro, K., Manral, V., Davey, A., and A. Lindem,
            "Traffic Engineering Extensions to OSPF Version 3", RFC
            5329, September 2008,
            <http://www.rfc-editor.org/info/rfc5329>.
 [RFC5440]  Vasseur, JP. and JL. Le Roux, "Path Computation Element
            (PCE) Communication Protocol (PCEP)", RFC 5440, March
            2009, <http://www.rfc-editor.org/info/rfc5440>.
 [RFC5512]  Mohapatra, P. and E. Rosen, "The BGP Encapsulation
            Subsequent Address Family Identifier (SAFI) and the BGP
            Tunnel Encapsulation Attribute", RFC 5512, April 2009,
            <http://www.rfc-editor.org/info/rfc5512>.
 [RFC5520]  Bradford, R., Vasseur, JP., and A. Farrel, "Preserving
            Topology Confidentiality in Inter-Domain Path Computation
            Using a Path-Key-Based Mechanism", RFC 5520, April 2009,
            <http://www.rfc-editor.org/info/rfc5520>.
 [RFC5521]  Oki, E., Takeda, T., and A. Farrel, "Extensions to the
            Path Computation Element Communication Protocol (PCEP) for
            Route Exclusions", RFC 5521, April 2009,
            <http://www.rfc-editor.org/info/rfc5521>.
 [RFC5640]  Filsfils, C., Mohapatra, P., and C. Pignataro, "Load-
            Balancing for Mesh Softwires", RFC 5640, August 2009,
            <http://www.rfc-editor.org/info/rfc5640>.
 [RFC5837]  Atlas, A., Bonica, R., Pignataro, C., Shen, N., and JR.
            Rivers, "Extending ICMP for Interface and Next-Hop
            Identification", RFC 5837, April 2010,
            <http://www.rfc-editor.org/info/rfc5837>.
 [RFC5884]  Aggarwal, R., Kompella, K., Nadeau, T., and G. Swallow,
            "Bidirectional Forwarding Detection (BFD) for MPLS Label
            Switched Paths (LSPs)", RFC 5884, June 2010,
            <http://www.rfc-editor.org/info/rfc5884>.
 [RFC5885]  Nadeau, T. and C. Pignataro, "Bidirectional Forwarding
            Detection (BFD) for the Pseudowire Virtual Circuit
            Connectivity Verification (VCCV)", RFC 5885, June 2010,
            <http://www.rfc-editor.org/info/rfc5885>.
 [RFC5886]  Vasseur, JP., Le Roux, JL., and Y. Ikejiri, "A Set of
            Monitoring Tools for Path Computation Element (PCE)-Based
            Architecture", RFC 5886, June 2010,
            <http://www.rfc-editor.org/info/rfc5886>.

George & Pignataro Informational [Page 24] RFC 7439 IPv6-Only MPLS January 2015

 [RFC5921]  Bocci, M., Bryant, S., Frost, D., Levrau, L., and L.
            Berger, "A Framework for MPLS in Transport Networks",
            RFC 5921, July 2010,
            <http://www.rfc-editor.org/info/rfc5921>.
 [RFC6006]  Zhao, Q., King, D., Verhaeghe, F., Takeda, T., Ali, Z.,
            and J. Meuric, "Extensions to the Path Computation Element
            Communication Protocol (PCEP) for Point-to-Multipoint
            Traffic Engineering Label Switched Paths", RFC 6006,
            September 2010, <http://www.rfc-editor.org/info/rfc6006>.
 [RFC6073]  Martini, L., Metz, C., Nadeau, T., Bocci, M., and M.
            Aissaoui, "Segmented Pseudowire", RFC 6073, January 2011,
            <http://www.rfc-editor.org/info/rfc6073>.
 [RFC6119]  Harrison, J., Berger, J., and M. Bartlett, "IPv6 Traffic
            Engineering in IS-IS", RFC 6119, February 2011,
            <http://www.rfc-editor.org/info/rfc6119>.
 [RFC6371]  Busi, I. and D. Allan, "Operations, Administration, and
            Maintenance Framework for MPLS-Based Transport Networks",
            RFC 6371, September 2011,
            <http://www.rfc-editor.org/info/rfc6371>.
 [RFC6388]  Wijnands, IJ., Minei, I., Kompella, K., and B. Thomas,
            "Label Distribution Protocol Extensions for Point-to-
            Multipoint and Multipoint-to-Multipoint Label Switched
            Paths", RFC 6388, November 2011,
            <http://www.rfc-editor.org/info/rfc6388>.
 [RFC6445]  Nadeau, T., Koushik, A., and R. Cetin, "Multiprotocol
            Label Switching (MPLS) Traffic Engineering Management
            Information Base for Fast Reroute", RFC 6445, November
            2011, <http://www.rfc-editor.org/info/rfc6445>.
 [RFC6513]  Rosen, E. and R. Aggarwal, "Multicast in MPLS/BGP IP
            VPNs", RFC 6513, February 2012,
            <http://www.rfc-editor.org/info/rfc6513>.
 [RFC6514]  Aggarwal, R., Rosen, E., Morin, T., and Y. Rekhter, "BGP
            Encodings and Procedures for Multicast in MPLS/BGP IP
            VPNs", RFC 6514, February 2012,
            <http://rfc-editor.org/info/rfc6514>.
 [RFC6540]  George, W., Donley, C., Liljenstolpe, C., and L. Howard,
            "IPv6 Support Required for All IP-Capable Nodes", BCP 177,
            RFC 6540, April 2012,
            <http://www.rfc-editor.org/info/rfc6540>.

George & Pignataro Informational [Page 25] RFC 7439 IPv6-Only MPLS January 2015

 [RFC6624]  Kompella, K., Kothari, B., and R. Cherukuri, "Layer 2
            Virtual Private Networks Using BGP for Auto-Discovery and
            Signaling", RFC 6624, May 2012,
            <http://www.rfc-editor.org/info/rfc6624>.
 [RFC6720]  Pignataro, C. and R. Asati, "The Generalized TTL Security
            Mechanism (GTSM) for the Label Distribution Protocol
            (LDP)", RFC 6720, August 2012,
            <http://www.rfc-editor.org/info/rfc6720>.
 [RFC6829]  Chen, M., Pan, P., Pignataro, C., and R. Asati, "Label
            Switched Path (LSP) Ping for Pseudowire Forwarding
            Equivalence Classes (FECs) Advertised over IPv6", RFC
            6829, January 2013,
            <http://www.rfc-editor.org/info/rfc6829>.
 [RFC7117]  Aggarwal, R., Kamite, Y., Fang, L., Rekhter, Y., and C.
            Kodeboniya, "Multicast in Virtual Private LAN Service
            (VPLS)", RFC 7117, February 2014,
            <http://www.rfc-editor.org/info/rfc7117>.

Acknowledgements

 The authors wish to thank Alvaro Retana, Andrew Yourtchenko, Loa
 Andersson, David Allan, Mach Chen, Mustapha Aissaoui, and Mark Tinka
 for their detailed reviews, as well as Brian Haberman, Joel Jaeggli,
 Adrian Farrel, Nobo Akiya, Francis Dupont, and Tobias Gondrom for
 their comments.

Contributors

 The following people have contributed text to this document:
    Rajiv Asati
    Cisco Systems
    7025 Kit Creek Road
    Research Triangle Park, NC 27709
    United States
    EMail: rajiva@cisco.com

George & Pignataro Informational [Page 26] RFC 7439 IPv6-Only MPLS January 2015

    Kamran Raza
    Cisco Systems
    2000 Innovation Drive
    Ottawa, ON K2K-3E8
    Canada
    EMail: skraza@cisco.com
    Ronald Bonica
    Juniper Networks
    2251 Corporate Park Drive
    Herndon, VA 20171
    United States
    EMail: rbonica@juniper.net
    Rajiv Papneja
    Huawei Technologies
    2330 Central Expressway
    Santa Clara, CA 95050
    United States
    EMail: rajiv.papneja@huawei.com
    Dhruv Dhody
    Huawei Technologies
    Leela Palace
    Bangalore, Karnataka 560008
    India
    EMail: dhruv.ietf@gmail.com
    Vishwas Manral
    Ionos Networks
    Sunnyvale, CA 94089
    United States
    EMail: vishwas@ionosnetworks.com

George & Pignataro Informational [Page 27] RFC 7439 IPv6-Only MPLS January 2015

    Nagendra Kumar
    Cisco Systems, Inc.
    7200 Kit Creek Road
    Research Triangle Park, NC 27709
    United States
    EMail: naikumar@cisco.com

Authors' Addresses

 Wesley George (editor)
 Time Warner Cable
 13820 Sunrise Valley Drive
 Herndon, VA  20111
 United States
 Phone: +1-703-561-2540
 EMail: wesley.george@twcable.com
 Carlos Pignataro (editor)
 Cisco Systems, Inc.
 7200-12 Kit Creek Road
 Research Triangle Park, NC  27709
 United States
 Phone: +1-919-392-7428
 EMail: cpignata@cisco.com

George & Pignataro Informational [Page 28]

/data/webs/external/dokuwiki/data/pages/rfc/rfc7439.txt · Last modified: 2015/01/07 22:44 by 127.0.0.1

Donate Powered by PHP Valid HTML5 Valid CSS Driven by DokuWiki