[Docs] [txt|pdf] [Tracker] [Email] [Diff1] [Diff2] [Nits]

Versions: (draft-abhattacharya-l2vpn-signaling-ipv6-remotepe) 00 01 02 03

INTERNET-DRAFT                                         Avik Bhattacharya
Updates: 6074 (if approved)                            Apratim Mukherjee
Intended Status: Standards Track                                    Ixia
Expires: August 23, 2015                               February 19, 2015


Provisioning, Auto-Discovery, and Signaling in L2VPNs for IPv6 Remote PE
            draft-abhattacharya-bess-l2vpn-ipv6-remotepe-03


Abstract

   L2VPN Signaling specification defines the semantic structure of the
   endpoint identifiers required by each model.  It discusses the
   distribution of these identifiers by the discovery process,
   especially when such discovery is based on the Border Gateway
   Protocol (BGP).  This document updates the end point encoding for
   BGP-Based Auto-Discovery and specifies a format for NLRI encoding for
   IPv6 PE Address. This document also specifies a new type of
   attachment identifier to carry IPv6 address as AII in LDP FEC 0x81.
   This document updates RFC6074.

Status of this Memo

   This Internet-Draft is submitted in full conformance with the
   provisions of BCP 78 and BCP 79.

   This document may contain material from IETF Documents or IETF
   Contributions published or made publicly available before November
   10, 2008. The person(s) controlling the copyright in some of this
   material may not have granted the IETF Trust the right to allow
   modifications of such material outside the IETF Standards Process.
   Without obtaining an adequate license from the person(s) controlling
   the copyright in such materials, this document may not be modified
   outside the IETF Standards Process, and derivative works of it may
   not be created outside the IETF Standards Process, except to format
   it for publication as an RFC or to translate it into languages other
   than English.

   Internet-Drafts are working documents of the Internet Engineering
   Task Force (IETF), its areas, and its working groups.  Note that
   other groups may also distribute working documents as Internet-
   Drafts.

   Internet-Drafts are draft documents valid for a maximum of six months
   and may be updated, replaced, or obsoleted by other documents at any
   time.  It is inappropriate to use Internet-Drafts as reference
   material or to cite them other than as "work in progress."



Bhattacharya, et al.    Expires August 23, 2015                 [Page 1]


INTERNET DRAFT     L2VPN signaling for IPv6 Remote PE  February 19, 2015


   The list of current Internet-Drafts can be accessed at
   http://www.ietf.org/ietf/1id-abstracts.txt

   The list of Internet-Draft Shadow Directories can be accessed at
   http://www.ietf.org/shadow.html


   This Internet-Draft will expire on August 23, 2015.






Copyright and License 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. This document may contain
   material from IETF Documents or IETF Contributions published or made
   publicly available before November 10, 2008.  The person(s)
   controlling the copyright in some of this material may not have
   granted the IETF Trust the right to allow modifications of such
   material outside the IETF Standards Process. Without obtaining an
   adequate license from the person(s) controlling the copyright in such
   materials, this document may not be modified outside the IETF
   Standards Process, and derivative works of it may not be created
   outside the IETF Standards Process, except to format it for
   publication as an RFC or to translate it into languages other than
   English.














Bhattacharya, et al.    Expires August 23, 2015                 [Page 2]


INTERNET DRAFT     L2VPN signaling for IPv6 Remote PE  February 19, 2015


Table of Contents

   1  Introduction  . . . . . . . . . . . . . . . . . . . . . . . . .  4
     1.1  Terminology . . . . . . . . . . . . . . . . . . . . . . . .  4
   2  BGP NLRI Format for the IPv6 PE Address . . . . . . . . . . . .  4
   3  Discussion on Route Distinguisher (RD) and Route Target (RT)  .  5
   4  Using IPv6 Remote PE address for signaling using LDP  . . . . .  5
   5  Interoperability in a mixed IPv4/IPv6 Network . . . . . . . . .  6
   6  Security Considerations . . . . . . . . . . . . . . . . . . . .  6
   7  IANA Considerations . . . . . . . . . . . . . . . . . . . . . .  7
   8. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . .  7
   9  References  . . . . . . . . . . . . . . . . . . . . . . . . . .  7
     9.1  Normative References  . . . . . . . . . . . . . . . . . . .  7
     9.2  Informative References  . . . . . . . . . . . . . . . . . .  8
   Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . .  8




































Bhattacharya, et al.    Expires August 23, 2015                 [Page 3]


INTERNET DRAFT     L2VPN signaling for IPv6 Remote PE  February 19, 2015


1  Introduction

   [RFC6074] specifies a number of L2VPN provisioning models, and
   further specifies the semantic structure of the endpoint identifiers
   required by each model. It discusses the distribution of these
   identifiers by the discovery process, especially when discovery is
   based on the Border Gateway Protocol (BGP).  It then specifies how
   the endpoint identifiers are carried in the two signaling protocols
   that are used to set up PWs, the Label Distribution Protocol (LDP),
   and the Layer 2 Tunneling Protocol version 3 (L2TPv3) [RFC6074].
   This document updates Section 3.2.2.1 of RFC 6074 (BGP-Based Auto-
   Discovery) and specifies a format for NLRI encoding that allows to
   carry also an IPv6 PE Address.This document also specifies a new type
   of attachment identifier to carry IPv6 address as AII in LDP FEC
   0x81. This gap in the specification of L2VPN in IPv6 only MPLS
   Network is also recognized in section 3.3.1 of [RFC7439].

1.1  Terminology

   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].

2  BGP NLRI Format for the IPv6 PE Address

   Section 3.2.2.1 of [RFC6074] specifies the BGP advertisement for a
   particular VSI at a given PE will contain:

      o  an NLRI of AFI = L2VPN, SAFI = VPLS, encoded as RD:PE_addr

      o  a BGP next hop equal to the loopback address of the PE

      o  an Extended Community Attribute containing the VPLS-id

      o  an Extended Community Attribute containing one or more RTs.

   The format for the NLRI encoding defined in Section 3.2.2.1 of
   [RFC6074] is:

           +------------------------------------+
           |  Length (2 octets)                 |
           +------------------------------------+
           |  Route Distinguisher (8 octets)    |
           +------------------------------------+
           |  PE_addr (4 octets)                |
           +------------------------------------+

           Figure 1: NLRI encoding in [RFC6074]



Bhattacharya, et al.    Expires August 23, 2015                 [Page 4]


INTERNET DRAFT     L2VPN signaling for IPv6 Remote PE  February 19, 2015


   In this format the size of the PE_addr is defined as 4 octets which
   can carry only IPv4 addresses. In a situation where the route is
   originating from a BGP end point running on an IPv6 address, the
   PE_addr in the NLRI needs to carry that IPv6 address. The updated
   format for the NLRI encoding is depicted in Figure 2.


           +------------------------------------+
           |  Length (2 octets)                 |
           +------------------------------------+
           |  Route Distinguisher (8 octets)    |
           +------------------------------------+
           |  PE_addr (4 or 16 octets)          |
           +------------------------------------+

           Figure 2: Updated NLRI encoding

   The length field MUST contain the sum of the length of the Length
   field(2), the length of the Route Distinguisher (8) and the length of
   the 4 or 16 octet PE_addr field.

   The type of the PE_addr can be derived by the receiving node by
   subtracting the fixed length of the Route Distinguisher and the
   Length field from the value of the received Length. An IPv4 PE_addr
   should be used to initiate adjacency of the underlying signaling
   protocol if it supports IPv4. An IPv6 PE_addr should be used to
   initiate adjacency of the underlying signaling protocol if it
   supports IPv6. (such as LDPv6)

3  Discussion on Route Distinguisher (RD) and Route Target (RT)

   Note that RD and RT can be in format AS 2byte + 4 byte Assigned
   Number or IP 4 byte + 2 byte Assigned Number [RFC4364]. Just like RD
   or RT cannot carry 4 byte AS numbers , they also cannot utilize 16
   byte IPv6 Address. Updates to RD and RT to operate in a pure IPv6
   environment is outside the scope of this document.

4  Using IPv6 Remote PE address for signaling using LDP

   Section 5.3.2 of [RFC4447] specifies the format of encoding for
   Generalized ID FEC Element (FEC 0x81)which is used for signaling in
   LDP. This document specifies a new type for AII carrying IPv6 address
   as TAII or SAII. (See Section 7)


   An FEC 0x81 TLV MUST contain SAII and TAII of the same type i.e.
   either type 1 or type 2.




Bhattacharya, et al.    Expires August 23, 2015                 [Page 5]


INTERNET DRAFT     L2VPN signaling for IPv6 Remote PE  February 19, 2015


5  Interoperability in a mixed IPv4/IPv6 Network

   If a VPLS instance is reachable though both IPv4 and IPv6 loopback in
   a PE node then the BGP instance(s) of that PE node MUST advertise the
   VPLS route using both NLRIs - one with IPv4 PE_addr and another with
   IPv6 PE_addr.

   While signaling a TAII in type 2 format, the LDP implementation MUST
   use SAII also in type 2 format. The value of the SAII MAY be set from
   the IPv6 loopback address on which the BGP session is established.

   While signaling a TAII type over an LDP session, on which it has
   already signaled with the other TAII type but with the same AGI, it
   SHOULD use the same label value in the Label Mapping for both TAII
   types.

   On receiving an FEC 0x81 TLV in a Label Advertisement with a TAII
   type, the LDP implementation MAY lookup if on the same LDP session it
   has received a Label Mapping with the other TAII type but for the
   same AGI. If yes then it MUST store the Label Mapping but MAY choose
   not to install the label. If it chooses not to do the lookup stated
   above then it MUST install the received label.

   If the LDP implementation chooses to do the lookup stated above
   during receipt of the Label Mapping, on receiving an FEC 0x81 TLV in
   a Label Withdraw with a TAII type, the LDP implementation MUST lookup
   if on the same LDP session it has received another Label Mapping with
   other TAII type but same AGI. If yes then it MUST install the stored
   Label Mapping and keep using that thereafter. ( Along with taking
   necessary actions for processing the Label Withdraw as specified in
   [RFC5036])


6  Security Considerations

   There is no additional security impact in addition to what is
   mentioned in [RFC6074].














Bhattacharya, et al.    Expires August 23, 2015                 [Page 6]


INTERNET DRAFT     L2VPN signaling for IPv6 Remote PE  February 19, 2015


7  IANA Considerations

   This document requires a new AII type to be used in Generalized ID
   FEC (0x81). IANA already maintains a registry of name "Attachment
   Individual Identifier(AII) Type" specified by [RFC4446].


   The following value is suggested for assignment:

   AII Type   Length       Description
   ===================================================================

   0x02         16         A 128 bit unsigned number local identifier.


8. Acknowledgments

   Thanks to Mohamed Boucadair for his valuable suggestions.




9  References

9.1  Normative References

   [RFC2119]  S. Bradner,"Key words for use in RFCs to Indicate
              Requirement Levels", BCP 14, RFC 2119, March 1997,
              <http://www.rfc-editor.org/info/rfc2119>.

   [RFC6074]  E. Rosen, B. Davie, "Provisioning, Auto-Discovery, and
              Signaling in Layer 2 Virtual Private Networks (L2VPNs)",
              BCP 74, RFC 6074, January 2011,
              <http://www.rfc-editor.org/info/rfc6074>.


   [RFC4446]  Martini, L., "IANA Allocations for Pseudowire Edge to Edge
              Emulation (PWE3)", BCP 116, RFC 4446, April 2006,
              <http://www.rfc-editor.org/info/rfc4446>.

   [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>.

   [RFC5036]  Andersson, L., Minei, I., and B. Thomas, "LDP
              Specification", RFC 5036, October
              2007,<http://www.rfc-editor.org/info/rfc5036>.



Bhattacharya, et al.    Expires August 23, 2015                 [Page 7]


INTERNET DRAFT     L2VPN signaling for IPv6 Remote PE  February 19, 2015


   [RFC7439]  W. George, C. Pignataro,, "Gap Analysis for Operating
              IPv6-Only MPLS Networks", RFC 7439, January
              2015,<http://www.rfc-editor.org/info/rfc7439>.

9.2  Informative References

   [RFC4364]  E. Rosen, "BGP/MPLS IP Virtual Private Networks (VPNs)",
              BCP 78, RFC 4364, February 2006,
              <http://www.rfc-editor.org/info/rfc4364>.







Authors' Addresses


              Avik Bhattacharya
              Ixia
              Infinity Building, Tower 2, Floor -4
              Sector 5, Saltlake,
              Kolkata, West Bengal, India - 700091.

              EMail: abhattacharya@ixiacom.com

              Apratim Mukherjee
              Ixia
              Infinity Building, Tower 2, Floor -4
              Sector 5, Saltlake,
              Kolkata, West Bengal, India - 700091.

              EMail: amukherjee@ixiacom.com

















Bhattacharya, et al.    Expires August 23, 2015                 [Page 8]


Html markup produced by rfcmarkup 1.123, available from https://tools.ietf.org/tools/rfcmarkup/