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

Versions: 00 01 02 03

Network Working Group                                          M. Smith
Internet Draft                                                  D. Dutt
Intended status: Experimental                             Cisco Systems
Expires: September 11, 2011                              March 11, 2011




                  Layer 2 (L2) LISP Encapsulation Format
                      draft-smith-lisp-layer2-00.txt


Abstract

   This memo describes an encapsulation method for carrying Ethernet
   and IEEE 802 media access control (MAC) frames within the Locator/ID
   Separation Protocol (LISP).

Status of this Memo

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

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

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

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

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

   This Internet-Draft will expire on September 11, 2011.

Copyright Notice

   Copyright (c) 2011 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



Smith, et al.         Expires September 11, 2011               [Page 1]

Internet-Draft  Layer 2 (L2) LISP Encapsulation Format       March 2011


   (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.

Table of Contents


   1. Introduction...................................................2
   2. Conventions used in this document..............................2
   3. Basic Overview.................................................3
   4. L2 LISP Encapsulation Details..................................4
      4.1. L2 LISP Header Format.....................................4
      4.2. Header Field Descriptions.................................4
   5. MTU Considerations.............................................5
   6. Security Considerations........................................5
   7. IANA Considerations............................................5
   8. References.....................................................6
      8.1. Normative References......................................6
      8.2. Informative References....................................6
   9. Acknowledgments................................................6

1. Introduction

   LISP [LISP] specifies an architecture and method for separating the
   location of an endpoint from its network identifier.  It does this
   by using two separate name spaces: EIDs representing the network
   identifier of the endpoint and RLOCs representing the network
   location of the endpoint.  This document extends the LISP
   specifications to allow Ethernet/IEEE 802 MAC frames to be carried
   within the LISP frame.  The MAC addresses of the encapsulated
   Ethernet/IEEE 802 MAC frames will be used as EIDs.

2. Conventions used in this document

   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
   "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
   document are to be interpreted as described in RFC-2119 [RFC2119].

   In this document, these words will appear with that interpretation
   only when in ALL CAPS. Lower case uses of these words are not to be
   interpreted as carrying RFC-2119 significance.




Smith, et al.         Expires September 11, 2011               [Page 2]

Internet-Draft  Layer 2 (L2) LISP Encapsulation Format       March 2011


3. Basic Overview

   L2 LISP specifies the mechanism on which to carry L2 traffic over a
   LISP network.  Within an L2 LISP environment, the source and
   destination MAC addresses of the Ethernet/IEEE 802.3 packet are used
   as the source and destination EIDs.  The RLOCs can use IPv4 or IPv6
   addressing.  The entire MAC frame is encapsulated with the exception
   of the preamble and trailing FCS. It should be noted that L2 LISP
   introduces the possibility of packet reordering during route
   topology changes due to the usage of IP as the network substrate.

   This memo addresses the data plane and frame format details of L2
   LISP.  The control plane details are outside the scope of this memo.




































Smith, et al.         Expires September 11, 2011               [Page 3]

Internet-Draft  Layer 2 (L2) LISP Encapsulation Format       March 2011


4. L2 LISP Encapsulation Details

  The L2 LISP encapsulation is based on the LISP header defined in the
  LISP specification [LISP].  The UDP and LISP headers are shown below
  for reference.

       0                   1                   2                   3
       0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
    / |       Source Port = xxxx      |       Dest Port = 4341        |
  UDP +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
    \ |           UDP Length          |        UDP Checksum           |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  L   |N|L|E|V|I|flags|            Nonce/Map-Version                  |
  I \ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  S / |                 Instance ID/Locator Status Bits               |
  P   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+


  When the headers are used for encapsulating L2 frames, the following
  settings are required:

       0                   1                   2                   3
       0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
    / |       Source Port = xxxx      |       Dest Port = 8472        |
  UDP +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
    \ |           UDP Length          |        UDP Checksum           |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  L   |0 0 0 0|I|0 0 0|                 Not Used                      |
  I \ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  S / |                 Instance ID                   |   Not Used    |
  P   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+


  The "Not Used" fields may be enabled in the future for usage in L2
  LISP by allocating an unused bit in the flags field.  This will be
  defined within the main LISP specification [LISP].

4.1. Header Field Descriptions

   UDP Header:  The UDP header contains a ITR selected source port when
      encapsulating a L2 LISP packet.  The source port allows routers
      and bridges in the network to load-split the traffic across the
      equal cost paths available.  The choice of the source port SHOULD
      be made based on a hash of some combination of the inner frame
      header fields such as but not limited to the source MAC address,


Smith, et al.         Expires September 11, 2011               [Page 4]

Internet-Draft  Layer 2 (L2) LISP Encapsulation Format       March 2011


      destination MAC address, Length/Ethertype, and IP header fields
      if present.  The destination port MUST be set to the well-known
      IANA assigned port value 8472.

   UDP Length:  The UDP length field is for an IPv4 encapsulated
      packet, the length of the inner L2 frame plus the UDP and LISP
      header lengths are used.  For an IPv6 encapsulated packet, the
      length of the inner L2 frame plus the size of the IPv6 header (40
      bytes) plus the size of the UDP and LISP headers are used.  The
      UDP header length is 8 bytes.

   UDP Checksum:  The UDP checksum field is used in accordance with the
      LISP specification [LISP].

   I: The I bit is the Instance ID bit.  When this bit is set to 1, it
      indicates that the Instance ID field carried the LISP header is
      valid.  In L2 LISP, this bit MUST be set to 1.

   Instance ID: An EID is scoped within the virtual L2 network which is
      specified through the usage of the Instance ID field.  The
      Instance ID namespace is contained within a single administrative
      domain.  The 24-bit Instance ID field is used in accordance with
      the LISP specification [LISP].

5. MTU Considerations

   Since additional tunnel headers are prepended, the packet becomes
   larger and can exceed the MTU of any link traversed from the ITR to
   the ETR.  It is recommended in IPv4 that packets do not get
   fragmented as they are encapsulated by the ITR.

6. Security Considerations

   Security in a network carrying L2 LISP should be similar to security
   in a normal IPv4 network.  Packet filtering on the L2 LISP inner
   frames will require that a firewall look inside the L2 LISP packet
   or that filtering is done at the ITR/ETR.

7. IANA Considerations

   The IANA registry has allocated UDP port number 8472 for the L2 LISP
   data packets.







Smith, et al.         Expires September 11, 2011               [Page 5]

Internet-Draft  Layer 2 (L2) LISP Encapsulation Format       March 2011


8. References

8.1. Normative References

   [802.1Q]  ANSI/IEEE Standard 802.1Q-2005, "IEEE Standards for Local
             and Metropolitan Area Networks: Virtual Bridged Local Area
             Networks", 2005.

   [LISP]    Farinacci, D., Fuller, V., Meyer, D., Lewis, D., draft-
             ietf-lisp-10.txt (work in progress), March 2011.

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

8.2. Informative References

9. Acknowledgments

   The authors would like to thank Dino Farinacci, Sumeet Singh, Ajit
   Sanzgiri, and Larry Kreeger for their technical and editorial
   commentary.

   This document was prepared using 2-Word-v2.0.template.dot.


























Smith, et al.         Expires September 11, 2011               [Page 6]

Internet-Draft  Layer 2 (L2) LISP Encapsulation Format       March 2011


Authors' Addresses

   Michael Smith
   Cisco Systems
   Tasman Drive
   San Jose, CA 95134

   Email: michsmit@cisco.com


   Dinesh Dutt
   Cisco Systems
   Tasman Drive
   San Jose, CA 95134

   Email: ddutt@cisco.com

































Smith, et al.         Expires September 11, 2011               [Page 7]


Html markup produced by rfcmarkup 1.107, available from http://tools.ietf.org/tools/rfcmarkup/