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Versions: 00 01 02 03 04 05 06 07 RFC 4798

Internet Engineering Task Force                             J. De Clercq
Internet-Draft                                            Alcatel-Lucent
Intended status: Standards Track                                 D. Ooms
Expires: June 15, 2007                                        OneSparrow
                                                              S. Prevost
                                                    BTexact Technologies
                                                          F. Le Faucheur
                                                                   Cisco
                                                       December 12, 2006


Connecting IPv6 Islands over IPv4 MPLS using IPv6 Provider Edge Routers
                                 (6PE)
                   draft-ooms-v6ops-bgp-tunnel-07.txt

Status of this Memo

   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 becomes
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   Internet-Drafts are working documents of the Internet Engineering
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   This Internet-Draft will expire on June 15, 2007.

Copyright Notice

   Copyright (C) The IETF Trust (2006).

Abstract

   This document explains how to interconnect IPv6 islands over a Multi-
   Protocol Label Switching (MPLS)-enabled IPv4 cloud.  This approach



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   relies on IPv6 Provider Edge routers (6PE) which are Dual Stack in
   order to connect to IPv6 islands and to the MPLS core which is only
   required to run IPv4 MPLS.  The 6PE routers exchange the IPv6
   reachability information transparently over the core using the Multi-
   Protocol Border Gateway Protocol (MP-BGP) over IPv4.  In doing so,
   the BGP Next Hop field is used to convey the IPv4 address of the 6PE
   router so that dynamically established IPv4-signaled MPLS Label
   Switched Paths (LSPs) can be used without explicit tunnel
   configuration.

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 [RFC2119].


Table of Contents

   1.  Introduction . . . . . . . . . . . . . . . . . . . . . . . . .  3
   2.  Protocol Overview  . . . . . . . . . . . . . . . . . . . . . .  5
   3.  Transport over IPv4-signaled LSPs and IPv6 label binding . . .  6
   4.  Crossing Multiple IPv4 Autonomous Systems  . . . . . . . . . .  8
   5.  Security Considerations  . . . . . . . . . . . . . . . . . . . 10
   6.  IANA Considerations  . . . . . . . . . . . . . . . . . . . . . 11
   7.  Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 11
   8.  References . . . . . . . . . . . . . . . . . . . . . . . . . . 11
     8.1.  Normative References . . . . . . . . . . . . . . . . . . . 11
     8.2.  Informative References . . . . . . . . . . . . . . . . . . 12
   Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 13
   Intellectual Property and Copyright Statements . . . . . . . . . . 14




















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1.  Introduction

   There are several approaches for providing IPv6 connectivity over an
   MPLS core network [RFC4029] including (i) requiring that MPLS
   networks support setting up IPv6-signaled Label Switched Paths (LSPs)
   and establish IPv6 connectivity by using those LSPs, (ii) use
   configured tunneling over IPv4-signaled LSPs, or (iii) use the IPv6
   Provider Edge (6PE) approach defined in this document.

   The 6PE approach is required as an alternative to the use of standard
   tunnels, because it provides a solution for an MPLS environment where
   all tunnels are established dynamically, thereby addressing
   environments where the effort to configure and maintain explicitly
   configured tunnels is not acceptable.

   This document specifies operations of the 6PE approach for
   interconnection of IPv6 islands over an IPv4 MPLS cloud.  The
   approach requires the edge routers that are connected to IPv6 islands
   to be Dual Stack Multi-Protocol-BGP-speaking routers [RFC2858bis]
   while the core routers are only required to run IPv4 MPLS.  The
   approach uses MP-BGP over IPv4, relies on identification of the 6PE
   routers by their IPv4 address and uses IPv4-signaled MPLS LSPs that
   don't require any explicit tunnel configuration.

   Throughout this document, the terminology of [RFC2460] and [RFC4364]
   is used.

   In this document an 'IPv6 island' is a network running native IPv6 as
   per [RFC2460].  A typical example of an IPv6 island would be a
   customer's IPv6 site connected via its IPv6 Customer Edge (CE) router
   to one (or more) Dual Stack Provider Edge router(s) of a Service
   Provider.  These IPv6 Provider Edge routers (6PE) are connected to an
   IPv4 MPLS core network.


       +--------+
       |site A  CE---+  +-----------------+
       +--------+    |  |                 |       +--------+
                    6PE-+  IPv4 MPLS core +-6PE--CE site C |
       +--------+    |  |                 |       +--------+
       |site B  CE---+  +-----------------+
       +--------+

        IPv6 islands          IPv4 cloud       IPv6 island
       <-------------><---------------------><-------------->


                                 Figure 1



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   The interconnection method described in this document typically
   applies to an Internet Service Provider (ISP) that has an IPv4 MPLS
   network and is familiar with BGP (possibly already offering BGP/MPLS
   VPN services) and that wants to offer IPv6 services to some of its
   customers.  However, the ISP may not (yet) want to upgrade its
   network core to IPv6 nor use only IPv6-over-IPv4 tunneling.  With the
   6PE approach described here, the provider only has to upgrade some
   Provider Edge (PE) routers to Dual Stack operations so they behave as
   6PE routers (and route reflectors if those are used for exchange of
   IPv6 reachability among 6PE routers) while leaving the IPv4 MPLS core
   routers untouched.  These 6PE routers provide connectivity to IPv6
   islands.  They may also provide other services simultaneously (IPv4
   connectivity, IPv4 L3VPN services, L2VPN services, etc.).  Also with
   the 6PE approach, no tunnels need to be explicitly configured, and no
   IPv4 headers need to be inserted in front of the IPv6 packets between
   the customer and provider edge.

   The ISP obtains IPv6 connectivity to its peers and upstreams using
   means outside of the scope of this memo, and its 6PE routers
   readvertise it over the IPv4 MPLS core with MP-BGP.

   The interface between the edge router of the IPv6 island (Customer
   Edge (CE) router) and the 6PE router is a native IPv6 interface which
   can be physical or logical.  A routing protocol (IGP or EGP) may run
   between the CE router and the 6PE router for the distribution of IPv6
   reachability information.  Alternatively, static routes and/or a
   default route may be used on the 6PE router and the CE router to
   control reachability.  An IPv6 island may connect to the provider
   network over more than one interface.

   The 6PE approach described in this document can be used for customers
   that already have an IPv4 service from the network provider and
   additionally require an IPv6 service, as well as for customers that
   require only IPv6 connectivity.

   The scenario is also described in [RFC4029].

   Note that the 6PE approach specified in this document provides global
   IPv6 reachability.  Support of IPv6 VPNs is not within the scope of
   this document and is addressed in [RFC4659].

   Deployment of the 6PE approach over an existing IPv4 MPLS cloud does
   not require introduction of new mechanisms in the core (other than
   potentially those described at the end of section 3 for dealing with
   dynamic MTU discovery).  Configuration and operations of the 6PE
   approach has a lot of similarities with the configuration and
   operations of an IPv4 VPN service ([RFC4364]) or IPv6 VPN service
   ([RFC4659]) over an IPv4 MPLS core since they all use MP-BGP to



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   distribute non-IPv4 reachability information for transport over an
   IPv4 MPLS Core.  However, the configuration and operations of the 6PE
   approach is somewhat simpler, since it does not involve all the VPN
   concepts such as VRFs.


2.  Protocol Overview

   Each IPv6 site is connected to at least one Provider Edge router that
   is located on the border of the IPv4 MPLS cloud.  We call such a
   router a 6PE router.  The 6PE router MUST be dual stack IPv4 and
   IPv6.  The 6PE router MUST be configured with at least one IPv4
   address on the IPv4 side and at least one IPv6 address on the IPv6
   side.  The configured IPv4 address needs to be routable in the IPv4
   cloud, and there needs to be a label bound via an IPv4 label
   distribution protocol to this IPv4 route.

   As a result of this, every considered 6PE router knows which MPLS
   label to use to send packets to any other 6PE router.  Note that an
   MPLS network offering BGP/MPLS IP VPN services already fulfills these
   requirements.

   No extra routes need to be injected in the IPv4 cloud.

   We call the 6PE router receiving IPv6 packets from an IPv6 site an
   Ingress 6PE router (relative to these IPv6 packets).  We call a 6PE
   router forwarding IPv6 packets to an IPv6 site an Egress 6PE router
   (relative to these IPv6 packets).

   Interconnecting IPv6 islands over an IPv4 MPLS cloud takes place
   through the following steps:

   1.  Exchange IPv6 reachability information among 6PE routers with MP-
       BGP [RFC2545]:

       The 6PE routers MUST exchange the IPv6 prefixes over MP-BGP
       sessions as per [RFC2545] running over IPv4.  The MP-BGP Address
       Family Identifier (AFI) used MUST be IPv6 (value 2).  In doing
       so, the 6PE routers convey their IPv4 address as the BGP Next Hop
       for the advertised IPv6 prefixes.  The IPv4 address of the egress
       6PE router MUST be encoded as an IPv4-mapped IPv6 address in the
       BGP Next Hop field.  This encoding is consistent with the
       definition of an IPv4-mapped IPv6 address in [RFC3513] as an
       "address type used to represent the address of IPv4 nodes as IPv6
       addresses".  In addition, the 6PE MUST bind a label to the IPv6
       prefix as per [RFC3107].  The Subsequence Address Family
       Identifier (SAFI) used in MP-BGP MUST be the "label" SAFI (value
       4) as defined in [RFC3107].  Rationale for this and label



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       allocation policies are discussed in section 3.

   2.  Transport IPv6 packets from Ingress 6PE router to Egress 6PE
       router over IPv4-signaled LSPs:

       The Ingress 6PE router MUST forward IPv6 data over the IPv4-
       signaled LSP towards the Egress 6PE router identified by the IPv4
       address advertised in the IPv4-mapped IPv6 address of the BGP
       Next Hop for the corresponding IPv6 prefix.

   As required by the BGP specification [RFC4271], PE routers form a
   full peering mesh unless Route Reflectors are used.


3.  Transport over IPv4-signaled LSPs and IPv6 label binding

   In this approach, the IPv4-mapped IPv6 addresses allow a 6PE router
   that has to forward an IPv6 packet to automatically determine the
   IPv4-signaled LSP to use for a particular IPv6 destination by looking
   at the MP-BGP routing information.

   The IPv4-signaled LSPs can be established using any existing
   technique for label setup [RFC3031] (LDP, RSVP-TE, ...).

   To ensure interoperability among systems that implement the 6PE
   approach described in this document, all such systems MUST support
   tunneling using IPv4-signaled MPLS LSPs established by LDP [RFC3036].

   When tunneling IPv6 packets over the IPv4 MPLS backbone, rather than
   successively prepend an IPv4 header and then perform label imposition
   based on the IPv4 header, the ingress 6PE Router MUST directly
   perform label imposition of the IPv6 header without prepending any
   IPv4 header.  The (outer) label imposed MUST correspond to the IPv4-
   signaled LSP starting on the ingress 6PE Router and ending on the
   egress 6PE Router.

   While this approach could theoretically operate in some situations
   using a single level of labels, there are significant advantages in
   using a second level of labels which are bound to IPv6 prefixes via
   MP-BGP advertisements in accordance with [RFC3107].

   For instance, use of a second level label allows Penultimate Hop
   Popping (PHP) on the IPv4 Label Switch Router (LSR) upstream of the
   egress 6PE router without any IPv6 capabilities/upgrade on the
   penultimate router; this is because it still transmits MPLS packets
   even after the PHP (instead of having to transmit IPv6 packets and
   encapsulate them appropriately).




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   Also, an existing IPv4-signaled LSP which is using "IPv4 Explicit
   NULL label" over the last hop (say because that LSP is already used
   to transport IPv4 traffic with the Pipe Diff-Serv Tunneling Model as
   defined in [RFC3270]) could not be used to carry IPv6 with a single
   label since the "IPv4 Explicit NULL label" can not be used to carry
   native IPv6 traffic (see [RFC3032]), while it could be used to carry
   labeled IPv6 traffic (see [RFC4182]).

   This is why a second label MUST be used with the 6PE approach.

   The label bound by MP-BGP to the IPv6 prefix indicates to the Egress
   6PE Router that the packet is an IPv6 packet.  This label advertised
   by the Egress 6PE Router with MP-BGP MAY be an arbitrary label value
   which identifies an IPv6 routing context or outgoing interface to
   send the packet to, or MAY be the IPv6 Explicit Null Label.  An
   Ingress 6PE Router MUST be able to accept any such advertised label.

   [RFC2460] requires that every link in the IPv6 Internet have an MTU
   of 1280 octets or larger.  Therefore, on MPLS links that are used for
   transport of IPv6 as per the 6PE approach and that do not support
   link-specific fragmentation and reassembly, the MTU must be
   configured to at least 1280 octets plus the encapsulation overhead.

   Some IPv6 hosts might be sending packets larger than the MTU
   available in the IPv4 MPLS core and rely on Path MTU discovery to
   learn about those links.  To simplify MTU discovery operations, one
   option is for the network administrator to engineer the MTU on the
   core facing interfaces of the ingress 6PE, consistent with the core
   MTU, so that ICMP 'Packet Too Big' messages can be sent back by the
   ingress 6PE without the corresponding packets ever entering the MPLS
   core.  Otherwise, routers in the IPv4 MPLS network have the option to
   generate an ICMP "Packet Too Big" message using mechanisms as
   described in section 2.3.2 "Tunneling Private Addresses through a
   Public Backbone" of [RFC3032].

   In that case, note that, should a core router with an outgoing link
   with a MTU smaller than 1280 receive an encapsulated IPv6 packet
   larger than 1280, then the mechanisms of [RFC3032] may result in the
   "Packet Too Big" message never reaching the sender.  This is because,
   according to [RFC2463], the core router will build an ICMP "Packet
   Too Big" message filled with the invoking packet up to 1280 bytes and
   when forwarding downstream towards the egress PE as per [RFC3032],
   the MTU of the outgoing link will cause the packet to be dropped.
   This may cause significant operational problems; the originator of
   the packets will notice that his data is not getting through, without
   knowing why and where they are discarded.  This issue would only
   occur if the above recommendation (to configure MTU on MPLS links of
   at least 1280 octets plus encapsulation overhead) is not adhered to



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   (perhaps by misconfiguration).


4.  Crossing Multiple IPv4 Autonomous Systems

   This section discusses the case where two IPv6 islands are connected
   to different Autonomous Systems.

   Like in the case of multi-AS backbone operations for IPv4 VPNs
   described in section 10 of [RFC4364], three main approaches can be
   distinguished:

   a.  EBGP redistribution of IPv6 routes from AS to neighboring AS

       This approach is the equivalent for exchange of IPv6 routes to
       procedure (a) described in section 10 of [RFC4364] for the
       exchange of VPN-IPv4 routes.

       In this approach, the 6PE routers use IBGP (according to
       [RFC2545] and [RFC3107] and as described in this document for the
       single-AS situation) to redistribute labeled IPv6 routes either
       to an Autonomous System Border Router (ASBR) 6PE router, or to a
       route reflector of which an ASBR 6PE router is a client.  The
       ASBR then uses EBGP to redistribute the (non-labeled) IPv6 routes
       to an ASBR in another AS, which in turn distributes them to the
       6PE routers in that AS as described earlier in this
       specification, or perhaps to another ASBR which in turn
       distributes them etc.

       There may be one, or multiple, ASBR interconnection(s) across any
       two ASes.  IPv6 needs to be activated on the inter-ASBR links and
       each ASBR 6PE router has at least one IPv6 address on the
       interface to that link.

       No inter-AS LSPs are used.  There is effectively a separate mesh
       of LSPs across the 6PE routers within each AS.

       In this approach, the ASBR exchanging IPv6 routes may peer over
       IPv6 or over IPv4.  The exchange of IPv6 routes MUST be carried
       out as per [RFC2545].

       Note that the peering ASBR in the neighboring AS to which the
       IPv6 routes were distributed with EBGP, should in its turn
       redistribute these routes to the 6PEs in its AS using IBGP and
       encoding its own IPv4 address as the IPv4-mapped IPv6 BGP Next
       Hop.





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   b.  EBGP redistribution of labeled IPv6 routes from AS to neighboring
       AS

       This approach is the equivalent for exchange of IPv6 routes to
       procedure (b) described in section 10 of [RFC4364] for the
       exchange of VPN-IPv4 routes.

       In this approach, the 6PE routers use IBGP (as described earlier
       in this document for the single-AS situation) to redistribute
       labeled IPv6 routes either to an Autonomous System Border Router
       (ASBR) 6PE router, or to a route reflector of which an ASBR 6PE
       router is a client.  The ASBR then uses EBGP to redistribute the
       labeled IPv6 routes to an ASBR in another AS, which in turn
       distributes them to the 6PE routers in that AS as described
       earlier in this specification, or perhaps to another ASBR which
       in turn distributes them etc.

       There may be one, or multiple, ASBR interconnection(s) across any
       two ASes.  IPv6 may or may not be activated on the inter-ASBR
       links.

       This approach requires that there be label switched paths
       established across ASes.  Hence the corresponding considerations
       described for procedure (b) in section 10 of [RFC4364] apply
       equally to this approach for IPv6.

       In this approach, the ASBR exchanging IPv6 routes may peer over
       IPv4 or IPv6 (in which case, IPv6 obviously needs to be activated
       on the inter-ASBR link).  When peering over IPv6, the exchange of
       labeled IPv6 routes MUST be carried out as per [RFC2545] and
       [RFC3107].  When peering over IPv4, the exchange of labeled IPv6
       routes MUST be carried out as per [RFC2545] and [RFC3107] with
       encoding of the IPv4 address of the ASBR as an IPv4-mapped IPv6
       address in the BGP Next Hop field.


   c.  Multihop EBGP redistribution of labeled IPv6 routes between
       source and destination ASes, with EBGP redistribution of labeled
       IPv4 routes from AS to neighboring AS.

       This approach is the equivalent for exchange of IPv6 routes to
       procedure (c) described in section 10 of [RFC4364] for exchange
       of VPN- IPv4 routes.

       In this approach, IPv6 routes are neither maintained nor
       distributed by the ASBR routers.  The ASBR routers need not be
       dual stack and may be IPv4/MPLS-only routers.  An ASBR needs to
       maintain labeled IPv4 /32 routes to the 6PE routers within its



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       AS.  It uses EBGP to distribute these routes to other ASes.
       ASBRs in any transit ASes will also have to use EBGP to pass
       along the labeled IPv4 /32 routes.  This results in the creation
       of an IPv4 label switched path from the ingress 6PE router to the
       egress 6PE router.  Now 6PE routers in different ASes can
       establish multi-hop EBGP connections to each other over IPv4, and
       can exchange labeled IPv6 routes (with an IPv4-mapped IPv6 BGP
       Next Hop) over those connections.

       IPv6 need not be activated on the inter-ASBR links.

       The considerations described for procedure (c) in section 10 of
       [RFC4364] with respect to possible use of multi-hop EBGP
       connections via route-reflectors in different ASes, as well as
       with respect to the use of a third label in case the IPv4 /32
       routes for the PE routers are NOT made known to the P routers,
       apply equally to this approach for IPv6.

       This approach requires that there be IPv4 label switched paths
       established across the ASes leading form a packet's ingress 6PE
       router to its egress 6PE router.  Hence, the considerations
       described for procedure (c) in section 10 of [RFC4364] with
       respect to LSPs spanning multiple ASes apply equally to this
       approach for IPv6.

       Note also that the exchange of IPv6 routes can only start after
       BGP has created IPv4 connectivity between the ASes.


5.  Security Considerations

   The extensions defined in this document allow BGP to propagate
   reachability information about IPv6 routes over an MPLS IPv4 core
   network.  As such, no new security issues are raised beyond those
   that already exist in BGP-4 and use of MP-BGP for IPv6.

   The security features of BGP and corresponding security policy
   defined in the ISP domain are applicable.

   For the inter-AS distribution of IPv6 routes according to case (a) of
   section 4 of this document, no new security issues are raised beyond
   those that already exist in the use of EBGP for IPv6 [RFC2545].

   For the inter-AS distribution of IPv6 routes according to case (b)
   and (c) of section 4 of this document, the procedures require that
   there be label switched paths established across the AS boundaries.
   Hence the appropriate trust relationships must exist between and
   among the set of ASes along the path.  Care must be taken to avoid



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   "label spoofing".  To this end an ASBR 6PE SHOULD only accept labeled
   packets from its peer ASBR 6PE if the topmost label is a label that
   it has explicitly signaled to that peer ASBR 6PE.

   Note that for the inter-AS distribution of IPv6 routes according to
   case (c) of section 4 of this document, label spoofing may be more
   difficult to prevent.  Indeed, the MPLS label distributed with the
   IPv6 routes via multi-hop EBGP is directly sent from the egress 6PE
   to ingress 6PEs in an other AS (or through route reflectors).  This
   label is advertised transparently through the AS boundaries.  When
   the egress 6PE that sent the labeled IPv6 routes receives a data
   packet that has this particular label on top of its stack, it may not
   be able to verify whether the label was pushed on the stack by an
   ingress 6PE that is allowed to do so.  As such one AS may be
   vulnerable to label spoofing in a different AS.  The same issue
   equally applies to the option (c) of section 10 of [RFC4364].  Just
   like it is the case for [RFC4364], addressing this particular
   security issue is for further study.


6.  IANA Considerations

   This document has no actions for IANA.


7.  Acknowledgements

   We wish to thank Gerard Gastaud and Eric Levy-Abegnoli who
   contributed to this document, and we wish to thank Tri T. Nguyen who
   initiated this document, but who unfortunately passed away much too
   soon.  We also thank Pekka Savola for his valuable comments and
   suggestions.


8.  References

8.1.  Normative References

   [RFC2119]  Bradner, S., "Key words for use in RFCs to Indicate
              Requirement Levels", BCP 14, RFC 2119, March 1997.

   [RFC2460]  Deering, S. and R. Hinden, "Internet Protocol, Version 6
              (IPv6) Specification", RFC 2460, December 1998.

   [RFC2545]  Marques, P. and F. Dupont, "Use of BGP-4 Multiprotocol
              Extensions for IPv6 Inter-Domain Routing", RFC 2545,
              March 1999.




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   [RFC2858bis]
              Bates, T., Rekhter, Y., Chandra, R., and D. Katz,
              "Multiprotocol Extensions for BGP-4",
               draft-ietf-idr-rfc2858bis-10.txt, work in progress.

   [RFC3032]  Rosen, E., Tappan, D., Fedorkow, G., Rekhter, Y.,
              Farinacci, D., Li, T., and A. Conta, "MPLS Label Stack
              Encoding", RFC 3032, January 2001.

   [RFC3036]  Andersson, L., Doolan, P., Feldman, N., Fredette, A., and
              B. Thomas, "LDP Specification", RFC 3036, January 2001.

   [RFC3107]  Rekhter, Y. and E. Rosen, "Carrying Label Information in
              BGP-4", RFC 3107, May 2001.

   [RFC3513]  Hinden, R. and S. Deering, "Internet Protocol Version 6
              (IPv6) Addressing Architecture", RFC 3513, April 2003.

8.2.  Informative References

   [RFC2463]  Conta, A. and S. Deering, "Internet Control Message
              Protocol (ICMPv6) for the Internet Protocol Version 6
              (IPv6) Specification", RFC 2463, December 1998.

   [RFC3031]  Rosen, E., Viswanathan, A., and R. Callon, "Multiprotocol
              Label Switching Architecture", RFC 3031, January 2001.

   [RFC3270]  Le Faucheur, F., Wu, L., Davie, B., Davari, S., Vaananen,
              P., Krishnan, R., Cheval, P., and J. Heinanen, "Multi-
              Protocol Label Switching (MPLS) Support of Differentiated
              Services", RFC 3270, May 2002.

   [RFC4029]  Lind, M., Ksinant, V., Park, S., Baudot, A., and P.
              Savola, "Scenarios and Analysis for Introducing IPv6 into
              ISP Networks", RFC 4029, March 2005.

   [RFC4182]  Rosen, E., "Removing a Restriction on the use of MPLS
              Explicit NULL", RFC 4182, September 2005.

   [RFC4271]  Rekhter, Y., Li, T., and S. Hares, "A Border Gateway
              Protocol 4 (BGP-4)", RFC 4271, January 2006.

   [RFC4364]  Rosen, E. and Y. Rekhter, "BGP/MPLS IP Virtual Private
              Networks (VPNs)", RFC 4364, February 2006.

   [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.



De Clercq, et al.         Expires June 15, 2007                [Page 12]

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Authors' Addresses

   Jeremy De Clercq
   Alcatel-Lucent
   Copernicuslaan 50
   Antwerpen  2018
   Belgium

   Email: jeremy.de_clercq@alcatel-lucent.be


   Dirk Ooms
   OneSparrow
   Belegstraat 13
   Antwerpen  2018
   Belgium

   Email: dirk@onesparrow.com


   Stuart Prevost
   BTexact Technologies
   Room 136 Polaris House, Adastral Park, Martlesham Heath
   Ipswich  Suffolk IP5 3RE
   England

   Email: stuart.prevost@bt.com


   Francois Le Faucheur
   Cisco
   Domaine Green Side 400, Avenue de Roumanille, Batiment T3
   Biot, Sophia Antipolis  06410
   France

   Email: flefauch@cisco.com















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