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Network Working Group                                           M. Smith
Internet-Draft                                          Insieme Networks
Intended status: Experimental                                    D. Dutt
Expires: January 14, 2013                               Cumulus Networks
                                                            D. Farinacci
                                                                F. Maino
                                                           Cisco Systems
                                                           July 13, 2012


                 Layer 2 (L2) LISP Encapsulation Format
                       draft-smith-lisp-layer2-01

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).

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 [RFC2119].

Status of this Memo

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

   Internet-Drafts are working documents of the Internet Engineering
   Task Force (IETF).  Note that other groups may also distribute
   working documents as Internet-Drafts.  The list of current Internet-
   Drafts is at http://datatracker.ietf.org/drafts/current/.

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

   This Internet-Draft will expire on January 14, 2013.

Copyright Notice

   Copyright (c) 2012 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



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   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
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   described in the Simplified BSD License.


Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . . . 3
   2.  Basic Overview  . . . . . . . . . . . . . . . . . . . . . . . . 3
   3.  Layer 2 LISP Encapsulation  . . . . . . . . . . . . . . . . . . 3
     3.1.  VXLAN . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
     3.2.  L2 LISP . . . . . . . . . . . . . . . . . . . . . . . . . . 5
   4.  MTU Considerations  . . . . . . . . . . . . . . . . . . . . . . 5
   5.  Overlays for Network Virtualization . . . . . . . . . . . . . . 6
   6.  LISP Mapping System . . . . . . . . . . . . . . . . . . . . . . 6
   7.  Security Considerations . . . . . . . . . . . . . . . . . . . . 7
   8.  IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 7
   9.  Acknowledgements  . . . . . . . . . . . . . . . . . . . . . . . 8
   10. References  . . . . . . . . . . . . . . . . . . . . . . . . . . 8
     10.1. Normative References  . . . . . . . . . . . . . . . . . . . 8
     10.2. Informative References  . . . . . . . . . . . . . . . . . . 8
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . . . 9
























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1.  Introduction

   LISP [I-D.ietf-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.  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.


3.  Layer 2 LISP Encapsulation

   The layer 2 LISP encapsulation is based on the LISP header defined in
   the LISP specification [I-D.ietf-lisp].  The UDP and LISP headers are
   shown below for reference.  For header fields description see section
   5.3 of [I-D.ietf-lisp].

        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
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |            IPv4 or IPv6 Header  (with RLOC addresses)         |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     / |       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   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+




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   When the headers are used for encapsulating L2 frames, the UDP
   Destination Port is set to 8472.

3.1.  VXLAN

   The VXLAN [I-D.mahalingam-dutt-dcops-vxlan] header is achieved by
   setting the L2 LISP header bits as shown in the figure below.
   According to [I-D.mahalingam-dutt-dcops-vxlan] the I flag MUST be set
   to 1 for a valid VXLAN Network ID (VNI).  The figure shows the whole
   VXLAN frame, including the original inner L2 frame.


        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
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |            IPv4 or IPv6 Header  (with RLOC addresses)         |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     / |       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   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     / |             Inner Destination MAC Address                     |
    I  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
    n  | Inner Destination MAC Address | Inner Source MAC Address      |
    n  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
    e  |                Inner Source MAC Address                       |
    r  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       | Opt. Eth.type = C-Tag [802.1Q]| Inner.VLAN Tag Information    |
    L  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
    2  | Ethertype of Original Payload |                               |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+                               |
    F  |                                                               |
    r  |                                                               |
    a  |                   Original Ethernet Payload                   |
    m  |                                                               |
    e  |                                                               |
     \ | (Note that the original Ethernet Frame's FCS is not included) |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |     FCS (Frame Check Sequence) for Outer Ethernet Frame       |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+







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3.2.  L2 LISP

   An L2 LISP frame may optionally use the entire set of fields in the
   LISP header to support all of the features of the LISP protocol.

   The figure below shows the whole L2 LISP frame, including the
   original inner L2 frame.


        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
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |            IPv4 or IPv6 Header  (with RLOC addresses)         |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     / |       Source Port = xxxx      |       Dest Port = 8472        |
   UDP +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     \ |           UDP Length          |        UDP Checksum           |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   L   |N|L|E|V|I|flags|            Nonce/Map-Version                  |
   I \ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   S / |                 Instance ID/Locator Status Bits               |
   P   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     / |             Inner Destination MAC Address                     |
    I  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
    n  | Inner Destination MAC Address | Inner Source MAC Address      |
    n  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
    e  |                Inner Source MAC Address                       |
    r  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       | Opt. Eth.type = C-Tag [802.1Q]| Inner.VLAN Tag Information    |
    L  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
    2  | Ethertype of Original Payload |                               |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+                               |
    F  |                                                               |
    r  |                                                               |
    a  |                   Original Ethernet Payload                   |
    m  |                                                               |
    e  |                                                               |
     \ | (Note that the original Ethernet Frame's FCS is not included) |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |     FCS (Frame Check Sequence) for Outer Ethernet Frame       |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+


4.  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.  [I-D.ietf-lisp] recommends in IPv4 that packets do not get



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   fragmented as they are encapsulated by the ITR.  Instead, the packet
   is dropped and an ICMP Too Big message is returned to the source.
   Section 5.4 of [I-D.ietf-lisp] recommends procedure to mitigate MTU
   issues for IPv4 or IPv6 packets.


5.  Overlays for Network Virtualization

   A notable use case for layer 2 LISP encapsulation is the use as an
   overlay-based network virtualization architecture to support multi-
   tenancy in large data center networks, as stated in
   [I-D.narten-nvo3-overlay-problem-statement].  In this use case, the
   24-bit Instance ID serves as virtual network instance ID (VNID) that
   is typically used to identify the tenants in large multi-tenant data
   centers.

   Packet replication in the underlay network to support broadcast,
   unknown unicast and multicast overlay services can be done by:

   o  Ingress replication

   o  Use of underlay multicast trees

   [I-D.ietf-lisp-multicast] and [I-D.farinacci-lisp-mr-signaling]
   specify how to map a multicast flow in the EID space during
   distribution tree setup and packet delivery in the underlay network.


6.  LISP Mapping System

   When the LISP mapping database system is used with L2 LISP, it must
   support the LISP Canonical Address Format (LCAF) specified in
   [I-D.farinacci-lisp-lcaf].  More specifically the mapping database
   system must support the use of MAC Addresses as LISP EIDs, and the
   use of Instance IDs as part of the lookup key.

   According to [I-D.farinacci-lisp-lcaf] the encoding format for the
   2-tuple <Instance-ID, MAC-address> is:













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        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
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |           AFI = 16387         |    Rsvd1     |     Flags      |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |    Type = 2   | IID mask-len  |            Length             |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |                         Instance ID                           |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |             AFI = 6           |    Layer-2 MAC Address  ...   |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |                    ... Layer-2 MAC Address                    |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

   In the case of a single instance of mapping database, no Instance ID
   is necessary, and the encoding format for the MAC address is shown
   below.  In this case an Ethernet IEEE 802.1Q VLAN tag may be part of
   the lookup key (encoded in an Instance ID field).


        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
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |             AFI = 6           |    Layer-2 MAC Address  ...   |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |                    ... Layer-2 MAC Address                    |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

   A mapping database system that supports both the LISP Canonical
   Address Format, and Instance ID is the LISP Delegated Database Tree
   [I-D.fuller-lisp-ddt].


7.  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.


8.  IANA Considerations

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






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9.  Acknowledgements

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


10.  References

10.1.  Normative References

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

10.2.  Informative References

   [I-D.farinacci-lisp-lcaf]
              Farinacci, D., Meyer, D., and J. Snijders, "LISP Canonical
              Address Format (LCAF)", draft-farinacci-lisp-lcaf-07 (work
              in progress), March 2012.

   [I-D.farinacci-lisp-mr-signaling]
              Farinacci, D. and M. Napierala, "LISP Control-Plane
              Multicast Signaling", draft-farinacci-lisp-mr-signaling-00
              (work in progress), July 2012.

   [I-D.fuller-lisp-ddt]
              Fuller, V. and D. Lewis, "LISP Delegated Database Tree",
              draft-fuller-lisp-ddt-01 (work in progress), March 2012.

   [I-D.ietf-lisp]
              Farinacci, D., Fuller, V., Meyer, D., and D. Lewis,
              "Locator/ID Separation Protocol (LISP)",
              draft-ietf-lisp-23 (work in progress), May 2012.

   [I-D.ietf-lisp-multicast]
              Farinacci, D., Meyer, D., Zwiebel, J., and S. Venaas,
              "LISP for Multicast Environments",
              draft-ietf-lisp-multicast-14 (work in progress),
              February 2012.

   [I-D.mahalingam-dutt-dcops-vxlan]
              Sridhar, T., Bursell, M., Kreeger, L., Dutt, D., Wright,
              C., Mahalingam, M., Duda, K., and P. Agarwal, "VXLAN: A
              Framework for Overlaying Virtualized Layer 2 Networks over
              Layer 3 Networks", draft-mahalingam-dutt-dcops-vxlan-01
              (work in progress), February 2012.

   [I-D.narten-nvo3-overlay-problem-statement]



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              Narten, T., Sridhavan, M., Dutt, D., Black, D., and L.
              Kreeger, "Problem Statement: Overlays for Network
              Virtualization",
              draft-narten-nvo3-overlay-problem-statement-02 (work in
              progress), June 2012.


Authors' Addresses

   Michael Smith
   Insieme Networks
   California
   USA

   Email: michsmit@insiemenetworks.com


   Dinesh Dutt
   Cumulus Networks
   California
   USA

   Email: ddutt@cumulusnetworks.com


   Dino Farinacci
   Cisco Systems
   170 Tasman Drive
   San Jose, California  95134
   USA

   Email: dino@cisco.com


   Fabio Maino
   Cisco Systems
   170 Tasman Drive
   San Jose, California  95134
   USA

   Email: fmaino@cisco.com










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