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

Versions: 00 01 02 03 04 05

Network Working Group                                       M. Boucadair
Internet-Draft                                              C. Jacquenet
Intended status: Experimental                                     Orange
Expires: June 16, 2017                                 December 13, 2016


 A Compact LISP Encapsulation Scheme to Transport IPv4 Packets over an
                              IPv6 Network
               draft-boucadair-lisp-v6-compact-header-04

Abstract

   The encapsulation scheme used by the Locator/ID Separation Protocol
   (LISP) may sometimes raise MTU issues at the cost of possibly
   degrading the overall performance of the LISP network, especially in
   IPv6 migration contexts.  This document proposes a new, more compact,
   encapsulation scheme that aims to accommodate such issues and
   facilitate LISP deployment for IPv6 migration purposes, in
   particular.  This compact header may be considered to provide IPv4
   over IPv6 connectivity for mobile LISP-capable devices.

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].

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 June 16, 2017.








Boucadair & Jacquenet     Expires June 16, 2017                 [Page 1]


Internet-Draft         Compact LISP Encapsulation          December 2016


Copyright Notice

   Copyright (c) 2016 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.

Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   3
   2.  A Compact LISP Header . . . . . . . . . . . . . . . . . . . .   6
     2.1.  C Flag  . . . . . . . . . . . . . . . . . . . . . . . . .   6
     2.2.  On the Use of IPv4-Embedded IPv6 RLOCs  . . . . . . . . .   7
     2.3.  Truncated TCP Header  . . . . . . . . . . . . . . . . . .   8
     2.4.  Compact LISP Header Format  . . . . . . . . . . . . . . .   8
   3.  LISP Encapsulation with the Compact Header Form . . . . . . .  10
     3.1.  UDP Packets . . . . . . . . . . . . . . . . . . . . . . .  10
     3.2.  TCP Packets . . . . . . . . . . . . . . . . . . . . . . .  11
     3.3.  Fragments . . . . . . . . . . . . . . . . . . . . . . . .  11
   4.  LISP Decapsulation with the Compact LISP Header . . . . . . .  12
     4.1.  Build an IPv4/UDP Header  . . . . . . . . . . . . . . . .  12
     4.2.  Build an IPv4/TCP Header  . . . . . . . . . . . . . . . .  12
   5.  A More Compact LISP Encapsulation Flavor  . . . . . . . . . .  13
     5.1.  LISP Encapsulation with the More Compact Header Form  . .  15
       5.1.1.  UDP Packets . . . . . . . . . . . . . . . . . . . . .  15
       5.1.2.  TCP Packets . . . . . . . . . . . . . . . . . . . . .  16
       5.1.3.  Fragments . . . . . . . . . . . . . . . . . . . . . .  16
     5.2.  LISP Decapsulation with the More Compact LISP Header  . .  16
       5.2.1.  Build an IPv4/UDP Header  . . . . . . . . . . . . . .  17
       5.2.2.  Build an IPv4/TCP Header  . . . . . . . . . . . . . .  17
   6.  Discussion  . . . . . . . . . . . . . . . . . . . . . . . . .  18
   7.  Security Considerations . . . . . . . . . . . . . . . . . . .  18
   8.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .  18
   9.  Acknowledgments . . . . . . . . . . . . . . . . . . . . . . .  19
   10. Normative references  . . . . . . . . . . . . . . . . . . . .  19
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .  19







Boucadair & Jacquenet     Expires June 16, 2017                 [Page 2]


Internet-Draft         Compact LISP Encapsulation          December 2016


1.  Introduction

   The base specification of the Locator/ID Separation Protocol (LISP,
   [RFC6830]) defines an encapsulation scheme for transporting packets
   between xTR routers.  When applied at the scale of the Internet, this
   encapsulation scheme may raise MTU issues because of the LISP
   overhead.  This overhead may be aggravated when IPv6 transfer
   capabilities are used to interconnect LISP sites.

   As a reminder, Figure 1 shows the format of an encapsulated TCP
   ([RFC0793]) packet over IPv6, while Figure 2 covers UDP ([RFC0768]).

        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
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     / |Version| Traffic Class |           Flow Label                  |
    /  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |   |         Payload Length        | Next Header=17|   Hop Limit   |
   v   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |                                                               |
   O   +                                                               +
   u   |                                                               |
   t   +                     Source Routing Locator                    +
   e   |                                                               |
   r   +                                                               +
       |                                                               |
   H   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   d   |                                                               |
   r   +                                                               +
       |                                                               |
   ^   +                  Destination Routing Locator                  +
   |   |                                                               |
    \  +                                                               +
     \ |                                                               |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     / |       Source Port = xxxx      |       Dest Port = 4341        |
   UDP +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     \ |           UDP Length          |        UDP Checksum           |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   L   |N|L|E|V|I|R|K|K|            Nonce/Map-Version                  |
   I \ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   S / |                 Instance ID/Locator-Status-Bits               |
   P   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     / |Version|  IHL  |Type of Service|          Total Length         |
    /  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |   |         Identification        |Flags|      Fragment Offset    |
   |   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   IH  |  Time to Live |    Protocol   |         Header Checksum       |



Boucadair & Jacquenet     Expires June 16, 2017                 [Page 3]


Internet-Draft         Compact LISP Encapsulation          December 2016


   |   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |   |                           Source EID                          |
    \  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     \ |                         Destination EID                       |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     / |          Source Port          |       Destination Port        |
    /  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |   |                        Sequence Number                        |
   |   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |   |                    Acknowledgment Number                      |
   |   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  TCP  |  Data |           |U|A|P|R|S|F|                               |
   |   | Offset| Reserved  |R|C|S|S|Y|I|            Window             |
   |   |       |           |G|K|H|T|N|N|                               |
   |   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |   |           Checksum            |         Urgent Pointer        |
   |   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
    \  |                      (Optional) Options                       |
     \ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

              Figure 1: LISP IPv4-in-IPv6 Header Format (TCP)






























Boucadair & Jacquenet     Expires June 16, 2017                 [Page 4]


Internet-Draft         Compact LISP Encapsulation          December 2016


        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
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     / |Version| Traffic Class |           Flow Label                  |
    /  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |   |         Payload Length        | Next Header=17|   Hop Limit   |
   v   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |                                                               |
   O   +                                                               +
   u   |                                                               |
   t   +                     Source Routing Locator                    +
   e   |                                                               |
   r   +                                                               +
       |                                                               |
   H   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   d   |                                                               |
   r   +                                                               +
       |                                                               |
   ^   +                  Destination Routing Locator                  +
   |   |                                                               |
    \  +                                                               +
     \ |                                                               |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     / |       Source Port = xxxx      |       Dest Port = 4341        |
   UDP +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     \ |           UDP Length          |        UDP Checksum           |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   L   |N|L|E|V|I|R|K|K|            Nonce/Map-Version                  |
   I \ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   S / |                 Instance ID/Locator-Status-Bits               |
   P   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     / |Version|  IHL  |Type of Service|          Total Length         |
    /  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |   |         Identification        |Flags|      Fragment Offset    |
   |   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   IH  |  Time to Live |    Protocol   |         Header Checksum       |
   |   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |   |                           Source EID                          |
    \  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     \ |                         Destination EID                       |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     / |           Source Port         |       Destination Port        |
   UDP +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     \ |           UDP Length          |        UDP Checksum           |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

              Figure 2: LISP IPv4-in-IPv6 Header Format (UDP)




Boucadair & Jacquenet     Expires June 16, 2017                 [Page 5]


Internet-Draft         Compact LISP Encapsulation          December 2016


   This document proposes a new LISP encapsulation scheme that aims to
   reduce the overhead induced by LISP encapsulation (i.e., the one
   defined in [RFC6830]) to transport IPv4 packets over an IPv6
   infrastructure.

   This proposal does not suggest to obsolete the current LISP base
   encapsulation mode as defined in [RFC6830].  Rather, this document
   proposes to associate a meaning with one of the reserved flag bits
   (see Section 5.3 of [RFC6830]) to explicitly indicate that, when the
   bit is set, compact LISP encapsulation is in use.  This bit is called
   the C-bit ("Compact" flag bit).  Defining this capability in the base
   LISP header will help experimenting this compact header and assess
   its efficiency.

   This document does not introduce an overhead compared to the
   encapsulation scheme in [RFC6830] given that the solution relies on a
   compact encoding.  Some examples to illustrate the compression ratio
   achieved with the proposed compact header are shown below.

                     +----------+--------------+-----------+-----------+
                     | Origin   | RFC6830      | Compact   | Compact   |
                     | Size     | IPv4-in-IPv6 | Header 1  | Header 2  |
      +--------------+----------+--------------+-----------+-----------+
      | TCP ACK      | 40 bytes | 96 bytes     | 68 bytes  | 64 bytes  |
      |              |          |              | Gain: 29% | Gain: 33% |
      +--------------+----------+--------------+-----------+-- --------+
      | RTP          | 60 bytes | 116 bytes    | 80 bytes  | 76 bytes  |
      |              |          |              | Gain: 31% | Gain: 34% |
      +--------------+----------+--------------+-----------+-----------+

   This document assumes that RLOCs can be encoded as prefixes.  One of
   the bits of "Unused Flags" in a Map-Register and Map-Reply can be
   used to explicitly indicate the enclosed locator is an IPv6 prefix.
   The length of the prefix can be 32, 40, 48, 56, 64, or 96 [RFC6052].
   The RLOC address will be built using the algorithm in [RFC6052].

2.  A Compact LISP Header

2.1.  C Flag

   In order to allow for the co-existence of both legacy LISP header and
   this compact new header, this document associates a meaning with one
   of the reserved flag bits in [RFC6830].  Concretely, Figure 3 shows
   the required change to the LISP header to support the new compact
   LISP header.






Boucadair & Jacquenet     Expires June 16, 2017                 [Page 6]


Internet-Draft         Compact LISP Encapsulation          December 2016


OLD:
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   L   |N|L|E|V|I|R|K|K|            Nonce/Map-Version                  |
   I \ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   S / |                 Instance ID/Locator-Status-Bits               |
   P   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

NEW:
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   L   |N|L|E|V|I|C|K|K|            Nonce/Map-Version                  |
   I \ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   S / |                 Instance ID/Locator-Status-Bits               |
   P   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

                    Figure 3: C-bit in the LISP Header

   The description of the remaining fields is the same as in [RFC6830]
   and [I-D.ietf-lisp-crypto].  Note, the definition of the C-bit does
   not interfere with the functionality provided by other flag bits.

   The use of the C-bit as defined in this document is encouraged in
   IPv6 migration contexts that rely upon IPv4-embedded IPv6 addresses,
   as defined in [RFC6052].  Concretely, IPv4-embedded IPv6 addresses
   are used to convey Source/Destination IPv4 EIDs in Source/Destination
   Routing Locators.

2.2.  On the Use of IPv4-Embedded IPv6 RLOCs

   Figure 4 summarizes how the IPv4-embedded IPv6 RLOCs are synthesized
   from IPv4 EIDs.  As discussed in [RFC6052], the "u" byte is set to
   zero.

    +---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+
    |     RLOC Prefix (64 bits)     | u |   EID(32)     | suffix    |
    +---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+

Where "suffix" is :

 * the concatenation of "Protocol" field of the Internet header
   as conveyed in the original packet and "source port" of the transport
   header of the original packet (Source IPv4-embedded IPv6 address).

 * the concatenation of a null octet and  "source port" of transport
   header of the original packet (Source IPv4-embedded IPv6 address).

                       Figure 4: IPv4-embedded RLOCs





Boucadair & Jacquenet     Expires June 16, 2017                 [Page 7]


Internet-Draft         Compact LISP Encapsulation          December 2016


2.3.  Truncated TCP Header

   In addition to the use of IPv4-embedded IPv6 addresses, this document
   proposes the use of a truncated TCP header as shown in Figure 5 to
   reduce the size of the LISP header.

TCP Header:
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |          Source Port          |       Destination Port        |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |                        Sequence Number                        |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |                    Acknowledgment Number                      |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |  Data |           |U|A|P|R|S|F|                               |
       | Offset| Reserved  |R|C|S|S|Y|I|            Window             |
       |       |           |G|K|H|T|N|N|                               |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |           Checksum            |         Urgent Pointer        |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |                      (Optional) Options                       |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

Truncated TCP Header:
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |                        Sequence Number                        |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |                    Acknowledgment Number                      |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |  Data |           |U|A|P|R|S|F|                               |
       | Offset| Reserved  |R|C|S|S|Y|I|            Window             |
       |       |           |G|K|H|T|N|N|                               |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |                      (Optional) Options                       |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

                      Figure 5: Truncated TCP Header

2.4.  Compact LISP Header Format

   The compact LISP header for a TCP packet is shown in Figure 6, while
   the compact LISP header for UDP is depicted in Figure 7.









Boucadair & Jacquenet     Expires June 16, 2017                 [Page 8]


Internet-Draft         Compact LISP Encapsulation          December 2016


      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
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   / |Version| Traffic Class |           Flow Label                  |
  /  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |   |         Payload Length        | Next Header=17|   Hop Limit   |
 |   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ =
 |   |                                                               | |
 I   +                Source Routing Locator (64 bits)               + |
 P   |                                                               | S
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ R
 H   |     u byte    |         Source EID ...                        | C
 E   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
 A   |     ....      |    Protocol   |  (Inner) Source Port          | |
 D   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ =
 E   |                                                               | |
 R   +            Destination Routing Locator (64 bits)              + |
 |   |                                                               | D
 |   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ S
 |   |     u byte    |          Destination EID ...                  | T
  \  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
   \ |     ....      |    00000000   |(Inner)Destination Port        | |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ =
   / |       Source Port = xxxx      |       Dest Port = 4341        |
 UDP +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   \ |           UDP Length          |        UDP Checksum           |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 L   |N|L|E|V|I|C|K|K|            Nonce/Map-Version                  |
 I \ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 S / |                 Instance ID/Locator-Status-Bits               |
 P   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |                        Sequence Number                        |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |                    Acknowledgment Number                      |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |  Data |           |U|A|P|R|S|F|                               |
     | Offset| Reserved  |R|C|S|S|Y|I|            Window             |
     |       |           |G|K|H|T|N|N|                               |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |                      (Optional) Options                       |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

              Figure 6: Compact LISP Header Format (TCP Case)








Boucadair & Jacquenet     Expires June 16, 2017                 [Page 9]


Internet-Draft         Compact LISP Encapsulation          December 2016


      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
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   / |Version| Traffic Class |           Flow Label                  |
  /  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |   |         Payload Length        | Next Header=17|   Hop Limit   |
 |   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ =
 |   |                                                               | |
 I   +                Source Routing Locator (64 bits)               + |
 P   |                                                               | S
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ R
 H   |     u byte    |         Source EID ...                        | C
 E   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
 A   |     ....      |    Protocol   |  (Inner) Source Port          | |
 D   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ =
 E   |                                                               | |
 R   +            Destination Routing Locator (64 bits)              + |
 |   |                                                               | D
 |   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ S
 |   |     u byte    |          Destination EID ...                  | T
  \  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
   \ |     ....      |    00000000   |(Inner)Destination Port        | |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ =
   / |       Source Port = xxxx      |       Dest Port = 4341        |
 UDP +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   \ |           UDP Length          |        UDP Checksum           |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 L   |N|L|E|V|I|C|K|K|            Nonce/Map-Version                  |
 I \ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 S / |                 Instance ID/Locator-Status-Bits               |
 P   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

              Figure 7: Compact LISP Header Format (UDP Case)

3.  LISP Encapsulation with the Compact Header Form

   Upon receipt of an IPv4 packet that needs to be forwarded over a
   LISP-enabled IPv6 infrastructure, the ITR proceeds as described in
   Section 3.1 for UDP packets and in Section 3.2 for TCP packets.
   Section 3.3 specifies how fragments are handled.

3.1.  UDP Packets

   o  Retrieve the destination/source RLOC IPv6 prefix.
   o  Concatenate the source RLOC IPv6 prefix, the u byte, the source
      IPv4 address, the "Protocol" as indicated in the IP header, and
      the source port number to form the source IPv6 address as




Boucadair & Jacquenet     Expires June 16, 2017                [Page 10]


Internet-Draft         Compact LISP Encapsulation          December 2016


      specified in Section 2.2 for non-fragmented packets and fragments
      that convey a transport header.
   o  Concatenate the destination RLOC IPv6 prefix, the u byte, the
      destination IPv4 address, a null octet, and the destination port
      number to form the destination IPv6 address as specified in
      Section 2.2 for non-fragmented packets and fragments that convey a
      transport header.
   o  Remove both the IP and UDP headers of the original packet.
   o  Prepend the LISP header with the C-flag set (Section 2.1).
   o  Prepend the UDP header.
   o  Prepend the IPv6 header.

3.2.  TCP Packets

   o  Retrieve the destination/source RLOC IPv6 prefix.
   o  Concatenate the source RLOC IPv6 prefix, the u byte, the source
      IPv4 address, the "Protocol" as indicated in the IP header, and
      the source port number to form the source IPv6 address as
      specified in Section 2.2 for non-fragmented packets and fragments
      that convey a transport header.
   o  Concatenate the destination RLOC IPv6 prefix, the u byte, the
      destination IPv4 address, a null octet, and the destination port
      number to form the destination IPv6 address as specified in
      Section 2.2 for non-fragmented packets and fragments that convey a
      transport header.
   o  Remove the IP header, the first 4 bytes of the TCP header, and the
      4 bytes right after the "window" field from the original TCP
      header (Section 2.3).
   o  Prepend the LISP header with the C-flag set (Section 2.1).
   o  Prepend the UDP header.
   o  Prepend the IPv6 header.

3.3.  Fragments

   o  Retrieve the destination/source RLOC IPv6 prefix.
   o  Concatenate the source RLOC IPv6 prefix, the u byte, the source
      IPv4 address, and 3 bytes the "Protocol" as indicated in the IP
      header, and 2 bytes paddings of "1".
   o  Concatenate the destination RLOC IPv6 prefix, the u byte, the
      destination IPv4 address, and 3 bytes paddings of "1".
   o  Remove both the IP header of the original packet.
   o  Prepend the LISP header with the C-flag set (Section 2.1).
   o  Prepend the UDP header.
   o  Prepend the IPv6 header.







Boucadair & Jacquenet     Expires June 16, 2017                [Page 11]


Internet-Draft         Compact LISP Encapsulation          December 2016


4.  LISP Decapsulation with the Compact LISP Header

   Upon receipt of a LISP packet with the C-bit set, the ETR proceeds as
   follows to extract the inner IP packets (Section 4.1 for UDP and
   Section 4.2 for TCP).

   The processing of the other flag bits is not detailed in this
   specification.  Other than encoding RLOCs as prefixes, the behavior
   defined in [RFC6830] is not impacted by this specification.

   Obviously if the C-bit is unset, xTR routers follow the behavior
   defined in [RFC6830].

   The UDP checksum setting and validation of LISP-encapsulated packets
   MUST follow the guidelines documented in Section 5.3 of [RFC6830].

4.1.  Build an IPv4/UDP Header

   o  Check whether the destination IPv6 address matches an RLOC prefix
      owned by the xTR.
   o  Extract the Source EID that is encoded in positions 72 to 103 of
      the Source IPv6 address.
   o  Extract the "Protocol" field that is encoded in positions 104 to
      111 of the Source IPv6 address.  This value is used to set the
      corresponding field in the IPv4 header of the de-capsulated
      packet.
   o  Extract the Source Port that is encoded in positions 112 to 127 of
      the Source IPv6 address, for non-fragmented packets and fragments
      that convey a transport header.
   o  Extract the Destination EID that is encoded in positions 72 to 103
      of the Destination IPv6 address.
   o  Extract the Destination Port that is encoded in positions 112 to
      127 of the Destination IPv6 address, for non-fragmented packets
      and fragments that convey a transport header.
   o  Remove the IPv6 header, the UDP header, and the LISP header.
   o  Use the extracted Source Port and Destination Port to build the
      UDP header.  Prepend the new UDP header.
   o  Use the extracted Source IP address, Destination IP address, and
      Protocol to build the IPv4 header.
   o  Prepend the new IPv4 header.

4.2.  Build an IPv4/TCP Header

   o  Check whether the destination IPv6 address matches an RLOC prefix
      owned by the xTR.
   o  Extract the Source EID that is encoded in positions 72 to 103 of
      the Source IPv6 address.




Boucadair & Jacquenet     Expires June 16, 2017                [Page 12]


Internet-Draft         Compact LISP Encapsulation          December 2016


   o  Extract the "Protocol" field that is encoded in positions 104 to
      111 of the Source IPv6 address.  This value is used to set the
      corresponding field in the IPv4 header of the de-capsulated
      packet.
   o  Extract the Source Port that is encoded in positions 112 to 127 of
      the Source IPv6 address, for non-fragmented packets and fragments
      that convey a transport header.
   o  Extract the Destination EID that is encoded in positions 72 to 103
      of the Destination IPv6 address.
   o  Extract the Destination Port that is encoded in positions 112 to
      127 of the Destination IPv6 address, for non-fragmented packets
      and fragments that convey a transport header.
   o  Remove the IPv6 header, UDP header, and LISP header.
   o  For non-fragmented packets and fragments that convey a transport
      header, prepend 4 bytes with the source/destination port number
      and insert 4 bytes right after the "window" field to build a
      proper TCP header.  The extracted Source Port and Destination Port
      are used in this step.
   o  Prepend an IPv4 header.  Use the extracted Source IP address,
      Destination IP address, and Protocol to build the IPv4 header.

5.  A More Compact LISP Encapsulation Flavor

   A more compact LISP encapsulation scheme can be considered if the
   following conditions are met:

   o  Compatibility with "u" byte is not required.
   o  The origin "Source Port" number is copied into the UDP header of
      the encapsulated packet, and vice versa.
   o  The LISP shim is split into two parts: 4 bytes that are placed
      right after the UDP header while "Instance ID/Locator-Status-Bits"
      are encoded in the last 32 bits of the source IPv4-embedded IPv6
      RLOC.

   This alternate proposal leads to a 4-byte overhead when transporting
   IPv4-over-IPv6 LISP packets for both TCP (Figure 8) and UDP
   (Figure 9).














Boucadair & Jacquenet     Expires June 16, 2017                [Page 13]


Internet-Draft         Compact LISP Encapsulation          December 2016


      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
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   / |Version| Traffic Class |           Flow Label                  |
  /  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |   |         Payload Length        | Next Header=17|   Hop Limit   |
 |   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ =
 |   |                                                               | |
 I   +                Source Routing Locator (64 bits)               + |
 P   |                                                               | S
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ R
 H   |                         Source EID                            | C
 E   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
 A   |                 Instance ID/Locator-Status-Bits               | |
 D   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ =
 E   |                                                               | |
 R   +            Destination Routing Locator (64 bits)              + |
 |   |                                                               | D
 |   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ S
 |   |                     Destination EID                           | T
  \  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
   \ |    00000000   |(Inner)Protocol|(Inner)Destination Port        | |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ =
   / | Source Port = Inner Src Port  |       Dest Port = 4341        |
 UDP +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   \ |           UDP Length          |        UDP Checksum           |
 L \ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 I | |N|L|E|V|I|C|K|K|            Nonce/Map-Version                  |
 S / +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 P   |                        Sequence Number                        |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |                    Acknowledgment Number                      |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |  Data |           |U|A|P|R|S|F|                               |
     | Offset| Reserved  |R|C|S|S|Y|I|            Window             |
     |       |           |G|K|H|T|N|N|                               |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |                      (Optional) Options                       |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

          Figure 8: More Compacted LISP Header Format (TCP Case)










Boucadair & Jacquenet     Expires June 16, 2017                [Page 14]


Internet-Draft         Compact LISP Encapsulation          December 2016


      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
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   / |Version| Traffic Class |           Flow Label                  |
  /  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |   |         Payload Length        | Next Header=17|   Hop Limit   |
 |   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ =
 |   |                                                               | |
 I   +                Source Routing Locator (64 bits)               + |
 P   |                                                               | S
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ R
 H   |                         Source EID                            | C
 E   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
 A   |                 Instance ID/Locator-Status-Bits               | |
 D   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ =
 E   |                                                               | |
 R   +            Destination Routing Locator (64 bits)              + |
 |   |                                                               | D
 |   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ S
 |   |                     Destination EID                           | T
  \  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
   \ |    00000000   |(Inner)Protocol|(Inner)Destination Port        | |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ =
   / | Source Port = Inner Src Port  |       Dest Port = 4341        |
 UDP +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   \ |           UDP Length          |        UDP Checksum           |
 L \ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 I | |N|L|E|V|I|C|K|K|            Nonce/Map-Version                  |
 S / +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 P

          Figure 9: More Compacted LISP Header Format (UDP Case)

5.1.  LISP Encapsulation with the More Compact Header Form

   Upon receipt of an IPv4 packet that needs to be forwarded over a
   LISP-enabled infrastructure, the ITR proceeds as follows:

5.1.1.  UDP Packets

   o  Retrieve the destination/source RLOC IPv6 prefix.
   o  Concatenate the source RLOC IPv6 prefix, the source IPv4 address,
      and the "Instance ID/Locator-Status-Bits" to form the source IPv6
      address as shown in Figure 9.
   o  Concatenate the destination RLOC IPv6 prefix, the destination IPv4
      address, a null octet, the "Protocol" as indicated in the IP
      header, and the destination port number to form the destination




Boucadair & Jacquenet     Expires June 16, 2017                [Page 15]


Internet-Draft         Compact LISP Encapsulation          December 2016


      IPv6 address as shown in Figure 9, for non-fragmented packets and
      fragments that convey a transport header.
   o  Remove the IPv4 header.
   o  Set the destination port number of the UDP header to 4341.
   o  Insert the LISP header right after the UDP header; the C-flag must
      be set (Section 2.1).
   o  Prepend the IPv6 header.

5.1.2.  TCP Packets

   o  Retrieve the destination/source RLOC IPv6 prefix.
   o  Concatenate the source RLOC IPv6 prefix, the source IPv4 address,
      and the "Instance ID/Locator-Status-Bits" to form the source IPv6
      address as shown in Figure 8.
   o  Concatenate the destination RLOC IPv6 prefix, the destination IPv4
      address, a null octet, the "Protocol" as indicated in the IP
      header, and the destination port number to form the destination
      IPv6 address as shown in Figure 8, for non-fragmented packets and
      fragments that convey a transport header.
   o  Remove the IPv4 header.
   o  Remove the first 4 bytes and the 4 bytes right after the "window"
      field of the TCP header (Section 2.3).
   o  Prepend the LISP header; the C-flag must be set (Section 2.1)..
   o  Prepend the UDP header.  Set to the source port number to the same
      port indicated in the original TCP header.  Set the destination
      port number of the UDP header to 4341.
   o  Prepend an IPv6 header.

5.1.3.  Fragments

   o  Retrieve the destination/source RLOC IPv6 prefix.
   o  Concatenate the source RLOC IPv6 prefix, the source IPv4 address,
      and the "Instance ID/Locator-Status-Bits" to form the source IPv6
      address as shown in Figure 9.
   o  Concatenate the destination RLOC IPv6 prefix, the destination IPv4
      address, a non-null octet, the "Protocol" as indicated in the IP
      header, and a null octet padding to form the destination IPv6
      address.
   o  Remove the IPv4 header.
   o  Insert the LISP header.
   o  Insert the UDP header with a destination port number set to 4341.
   o  Prepend the IPv6 header.

5.2.  LISP Decapsulation with the More Compact LISP Header

   Upon receipt of a LISP packet with the C-bit set, the ETR proceeds as
   follows to extract the inner IP packets: (Figure 9 for UDP and
   Figure 8 for TCP).  Like in Section 2, the UDP checksum setting and



Boucadair & Jacquenet     Expires June 16, 2017                [Page 16]


Internet-Draft         Compact LISP Encapsulation          December 2016


   validation of LISP-encapsulated packets MUST follow the guidelines
   documented in Section 5.3 of [RFC6830].

5.2.1.  Build an IPv4/UDP Header

   o  Check whether the destination IPv6 address matches an RLOC prefix
      owned by the xTR.
   o  Extract the Source EID that is encoded in positions 64 to 95 of
      the Source IPv6 address.
   o  Extract the "Instance ID/Locator-Status-Bits" field that is
      encoded in positions 96 to 127 of the Source IPv6 address.
   o  Extract the Destination EID that is encoded in positions 64 to 95
      of the Destination IPv6 address.
   o  Extract the "Protocol" that is encoded in positions 104 to 111 of
      the Destination IPv6 address.
   o  Extract the Destination Port that is encoded in positions 112 to
      127 of the Destination IPv6 address if the octet in positions 96
      to 103 is not null.
   o  Remove the IPv6 header, the UDP header, and the LISP header.
   o  For non-fragmented packets and fragments that convey a transport
      header, use the extracted Source Port and Destination Port to
      build the UDP header.  Prepend the new UDP header.
   o  Use the extracted Source IPv4 address, Destination IPv4 address,
      and Protocol to build the IPv4 header.  Prepend the new IPv4
      header.

5.2.2.  Build an IPv4/TCP Header

   o  Check whether the destination IPv6 address matches an RLOC prefix
      owned by the xTR.
   o  Extract the Source EID that is encoded in positions 64 to 95 of
      the Source IPv6 address.
   o  Extract the "Instance ID/Locator-Status-Bits" field that is
      encoded in positions 96 to 127 of the Source IPv6 address.
   o  Extract the Destination EID that is encoded in positions 64 to 95
      of the Destination IPv6 address.
   o  Extract the "Protocol" that is encoded in positions 104 to 111 of
      the Destination IPv6 address.
   o  Extract the Destination Port that is encoded in positions 112 to
      127 of the Destination IPv6 address if the octet in positions 96
      to 103 is not null.
   o  Check whether the destination IPv6 address matches an RLOC prefix
      owned by the xTR.
   o  Remove the IPv6 header, UDP header, and LISP header.
   o  For non-fragmented packets and fragments that convey a transport
      header, prepend 4 bytes with the source/destination port number
      and insert 4 bytes right after the "window" field to build a




Boucadair & Jacquenet     Expires June 16, 2017                [Page 17]


Internet-Draft         Compact LISP Encapsulation          December 2016


      proper TCP header.  The extracted Source Port and Destination Port
      are used during this step.
   o  Prepend an IPv4 header.  Use the extracted Source IP address,
      Destination IP address, and Protocol to build the IPv4 header.

6.  Discussion

   The proposed compact headers are experimental.  What primarily
   motivates this specification is the need to assess its technical
   feasibility thanks to an existing LISP-enabled platform.  Experiments
   will help evaluate the gain brought by using such compact headers
   compared to base LISP encapsulation scheme in typical IPv6 migration
   scenarios

   The proposed compact encapsulation schemes guarantee a functional
   parity with the base LISP specification, given that the signalling
   carried in a LISP packet remains usable.

   This specification does not include any capability checks to ensure
   that remote xTRs support the proposed header encoding.  Particularly,
   deployability considerations in multi-domain LISP environments are
   not detailed in this document.

   This specification assumes that a configuration parameter should be
   supported by LISP implementations to tweak the encapsulation scheme
   to be used.

   The handling of fragmented packets by an ETR follows the same steps
   as in Section 2 except that, for the fragments that do not carry the
   source/destination port numbers, a non-null octet of the "suffix"
   defined Figure 4 is used to signal that the LISP-encapsulated packet
   is a fragment that does not convey transport-related information.

7.  Security Considerations

   The security considerations discussed in Section 12 of[RFC6830] are
   valid for this document.

   Security considerations related to building an IPv4-embedded IPv6
   address are discussed in [RFC6052].

8.  IANA Considerations

   This document does not make any request to IANA.







Boucadair & Jacquenet     Expires June 16, 2017                [Page 18]


Internet-Draft         Compact LISP Encapsulation          December 2016


9.  Acknowledgments

   This work is partly funded by ANR LISP-Lab project #ANR-13-INFR-
   009-X.

   Many thanks to S.  Secci, L.  Iannone, and J.  Saldana for the review
   and comments.

   The gain ratio table is a courtesy of J.  Saldana.

10.  Normative references

   [I-D.ietf-lisp-crypto]
              Farinacci, D. and B. Weis, "LISP Data-Plane
              Confidentiality", draft-ietf-lisp-crypto-10 (work in
              progress), October 2016.

   [RFC0768]  Postel, J., "User Datagram Protocol", STD 6, RFC 768,
              DOI 10.17487/RFC0768, August 1980,
              <http://www.rfc-editor.org/info/rfc768>.

   [RFC0793]  Postel, J., "Transmission Control Protocol", STD 7,
              RFC 793, DOI 10.17487/RFC0793, September 1981,
              <http://www.rfc-editor.org/info/rfc793>.

   [RFC2119]  Bradner, S., "Key words for use in RFCs to Indicate
              Requirement Levels", BCP 14, RFC 2119,
              DOI 10.17487/RFC2119, March 1997,
              <http://www.rfc-editor.org/info/rfc2119>.

   [RFC6052]  Bao, C., Huitema, C., Bagnulo, M., Boucadair, M., and X.
              Li, "IPv6 Addressing of IPv4/IPv6 Translators", RFC 6052,
              DOI 10.17487/RFC6052, October 2010,
              <http://www.rfc-editor.org/info/rfc6052>.

   [RFC6830]  Farinacci, D., Fuller, V., Meyer, D., and D. Lewis, "The
              Locator/ID Separation Protocol (LISP)", RFC 6830,
              DOI 10.17487/RFC6830, January 2013,
              <http://www.rfc-editor.org/info/rfc6830>.

Authors' Addresses

   Mohamed Boucadair
   Orange
   Rennes  35000
   France

   EMail: mohamed.boucadair@orange.com



Boucadair & Jacquenet     Expires June 16, 2017                [Page 19]


Internet-Draft         Compact LISP Encapsulation          December 2016


   Christian Jacquenet
   Orange
   Rennes  35000
   France

   EMail: christian.jacquenet@orange.com













































Boucadair & Jacquenet     Expires June 16, 2017                [Page 20]


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