Network Working Group                                        J. Laganier
Internet-Draft                                          DoCoMo Euro-Labs
Expires: January 12, 2006                                      L. Eggert
                                                                     NEC
                                                           July 11, 2005


           Host Identity Protocol (HIP) Rendezvous Extension
                         draft-ietf-hip-rvs-03

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   This Internet-Draft will expire on January 12, 2006.

Copyright Notice

   Copyright (C) The Internet Society (2005).

Abstract

   This document defines a rendezvous extension for the Host Identity
   Protocol (HIP).  The rendezvous extension extends HIP and the HIP
   registration extension for initiating communication between HIP nodes
   via HIP rendezvous servers.  Rendezvous servers improve reachability
   and operation when HIP nodes are multi-homed or mobile.





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Table of Contents

   1.  Introduction . . . . . . . . . . . . . . . . . . . . . . . . .  3
   2.  Terminology  . . . . . . . . . . . . . . . . . . . . . . . . .  3
   3.  Overview of Rendezvous Server Operation  . . . . . . . . . . .  4
     3.1   Diagram Notation . . . . . . . . . . . . . . . . . . . . .  5
     3.2   Rendezvous Client Registration . . . . . . . . . . . . . .  5
     3.3   Relaying the Base Exchange . . . . . . . . . . . . . . . .  6
   4.  Rendezvous Server Extensions . . . . . . . . . . . . . . . . .  7
     4.1   RENDEZVOUS Registration Type . . . . . . . . . . . . . . .  7
     4.2   Parameter Formats and Processing . . . . . . . . . . . . .  7
       4.2.1   RVS_HMAC Parameter . . . . . . . . . . . . . . . . . .  7
       4.2.2   FROM Parameter . . . . . . . . . . . . . . . . . . . .  8
       4.2.3   VIA_RVS Parameter  . . . . . . . . . . . . . . . . . .  9
     4.3   Modified Packets Processing  . . . . . . . . . . . . . . .  9
       4.3.1   Processing Outgoing I1 Packets . . . . . . . . . . . .  9
       4.3.2   Processing Incoming I1 packets . . . . . . . . . . . . 10
       4.3.3   Processing Outgoing R1 Packets . . . . . . . . . . . . 10
       4.3.4   Processing Incoming R1 packets . . . . . . . . . . . . 10
   5.  Security Considerations  . . . . . . . . . . . . . . . . . . . 10
   6.  IANA Considerations  . . . . . . . . . . . . . . . . . . . . . 11
   7.  Acknowledgments  . . . . . . . . . . . . . . . . . . . . . . . 11
   8.  References . . . . . . . . . . . . . . . . . . . . . . . . . . 12
     8.1   Normative References . . . . . . . . . . . . . . . . . . . 12
     8.2   Informative References . . . . . . . . . . . . . . . . . . 12
       Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . 13
   A.  Document Revision History  . . . . . . . . . . . . . . . . . . 14
       Intellectual Property and Copyright Statements . . . . . . . . 15























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1.  Introduction

   The Host Identity Protocol architecture [I-D.ietf-hip-arch]
   introduces the rendezvous mechanism to help a HIP node to contact a
   frequently moving HIP node.  The rendezvous mechanism involves a
   third party, the rendezvous server (RVS), which serves as an initial
   contact point ("rendezvous point") for its clients.  The clients of
   an RVS are HIP nodes that use the HIP Registration Protocol
   [I-D.koponen-hip-registration] to register their HIT->IP address
   mappings with the RVS.  After this registration, other HIP nodes can
   initiate a base exchange using the IP address of the RVS instead of
   the current IP address of the node they attempt to contact.
   Essentially, the clients of an RVS become reachable at the RVS' IP
   addresses.  Peers can initiate a HIP base exchange with the IP
   address of the RVS, which will relay this initial communication such
   that the base exchange may successfully complete.

2.  Terminology

   This section defines terms used throughout the remainder of this
   specification.

   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 addition to the terminology defined in [I-D.koponen-hip-
   registration], this document defines and uses the following terms:

   Rendezvous Service
      A HIP service provided by a rendezvous server to its rendezvous
      clients.  The rendezvous server offers to relay some of the
      arriving base exchange packets between the initiator and
      responder.

   Rendezvous Server (RVS)
      A HIP registrar providing rendezvous service.

   Rendezvous Client
      A HIP requester that has registered for rendezvous service at a
      rendezvous server.

   Rendezvous Registration
      A HIP registration for rendezvous service, established between a
      rendezvous server and a rendezvous client.






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3.  Overview of Rendezvous Server Operation

   Figure 1 shows a simple HIP base exchange without a rendezvous
   server, in which the initiator initiates the exchange directly with
   the responder by sending an I1 packet to the responder's IP address,
   as per the HIP base specification [I-D.ietf-hip-base].

                       +-----+                +-----+
                       |     |-------I1------>|     |
                       |  I  |<------R1-------|  R  |
                       |     |-------I2------>|     |
                       |     |<------R2-------|     |
                       +-----+                +-----+

          Figure 1: HIP base exchange without rendezvous server.

   Proposed extensions for mobility and multi-homing [I-D.ietf-hip-mm]
   allow a HIP node to notify its peers about changes in its set of IP
   addresses.  These extensions presumes initial reachability of the two
   nodes with respect to each other.

   However, such a HIP node MAY also want to be reachable to other
   future correspondent peers that are unaware of its location change.
   The HIP architecture [I-D.ietf-hip-arch] introduces rendezvous
   servers with whom a HIP node MAY register its host identity tags
   (HITs) and current IP addresses.  An RVS relays HIP packets arriving
   for these HITs to the node's registered IP addresses.  When a HIP
   node has registered with an RVS, it SHOULD record the IP address of
   its RVS in its DNS record, using the HIPRVS DNS record type defined
   in [I-D.ietf-hip-dns].

                                   +-----+
                          +--I1--->| RVS |---I1--+
                          |        +-----+       |
                          |                      v
                       +-----+                +-----+
                       |     |<------R1-------|     |
                       |  I  |-------I2------>|  R  |
                       |     |<------R2-------|     |
                       +-----+                +-----+

           Figure 2: HIP base exchange with a rendezvous server.

   Figure 2 shows a HIP base exchange involving a rendezvous server.  It
   is assumed that HIP node R previously registered its HITs and current
   IP addresses with the RVS, using the HIP registration protocol
   [I-D.koponen-hip-registration].  When the initiator I tries to
   establish contact with the responder R, it must send the I1 of the



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   base exchange either to one of R's IP addresses (if known via DNS or
   other means) or to one of R's rendezvous servers instead.  Here, I
   obtains the IP address of R's rendezvous server from R's DNS record
   and then sends the I1 packet of the HIP base exchange to RVS.  RVS,
   noticing that the HIT contained in the arriving I1 packet is not one
   of its own, MUST check its current registrations to determine if if
   needs to relay the packets.  Here, it determines that the HIT belongs
   to R and then relays the I1 packet to the registered IP address.  R
   then completes the base exchange without further assistance from RVS
   by sending an R1 directly to the I's IP address, as obtained from the
   I1 packet.  In this specification the client of the RVS is always the
   responder.  However, there might be reasons to allow a client to
   initiate a base exchange through its own RVS, like NAT and firewall
   traversal.  This specification does not address such scenarios which
   should be specified in other documents.

3.1  Diagram Notation

   Notation       Significance
   --------       ------------

   I, R           I and R are the respective source and destination IP
                  addresses in the IP header.

   HIT-I, HIT-R   HIT-I and HIT-R are the initiator's and the
                  responder's HITs in the packet, respectively.

   REG_REQ        A REG_REQUEST parameter is present in the HIP header.

   REG_RES        A REG_RESPONSE parameter is present in the HIP header.

   FROM:I         A FROM parameter containing the IP address I is
                  present in the HIP header.

   RVS_HMAC       A RVS_HMAC parameter containing a HMAC keyed with the
                  appropriate registration key is present in the HIP
                  header.

   VIA:RVS        A VIA_RVS parameter containing the IP address RVS of a
                  rendezvous server is present in the HIP header.


3.2  Rendezvous Client Registration

   Before a rendezvous server starts to relay HIP packets to a
   rendezvous client, the rendezvous client needs to register with it to
   receive rendezvous service by using the HIP registration extension
   [I-D.koponen-hip-registration] as illustrated in the following



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   schema:

                 +-----+                            +-----+
                 |     |            I1              |     |
                 |     |--------------------------->|     |
                 |     |<---------------------------|     |
                 |  I  |         R1(REG_INFO)       | RVS |
                 |     |         I2(REG_REQ)        |     |
                 |     |--------------------------->|     |
                 |     |<---------------------------|     |
                 |     |         R2(REG_RES)        |     |
                 +-----+                            +-----+


3.3  Relaying the Base Exchange

   If a HIP node and one of its rendezvous servers have a rendezvous
   registration, the rendezvous servers relay inbound I1 packets that
   contain one of the client's HITs by rewriting the IP header.  They
   replace the destination IP address of the I1 packet with one of the
   IP addresses of the owner of the HIT, i.e., the rendezvous client.
   They MUST also recompute the IP checksum accordingly.

   Because of egress filtering on the path from the RVS to the client
   [RFC2827][RFC3013], a HIP rendezvous server SHOULD replace the source
   IP address, i.e., the IP address of I, with one of its own IP
   addresses.  The replacement IP address SHOULD be chosen according to
   [RFC1122] and, when IPv6 is used,  to [RFC3484].  Because this
   replacement conceals the initiator's IP address, the RVS MUST append
   a FROM parameter containing the original source IP address of the
   packet.  This FROM parameter MUST be integrity protected by a
   RVS_HMAC keyed with the corresponding rendezvous registration
   integrity key [I-D.koponen-hip-registration].

                                               I1(RVS, R, HIT-I, HIT-R
         I1(I, RVS, HIT-I, HIT-R) +---------+     FROM:I, RVS_HMAC)
         +----------------------->|         |--------------------+
         |                        |   RVS   |                    |
         |                        |         |                    |
         |                        +---------+                    |
         |                                                       V
        +-----+        R1(R, I, HIT-R, HIT-I, VIA:RVS)       +-----+
        |     |<---------------------------------------------|     |
        |     |                                              |     |
        |  I  |            I2(I, R, HIT-I, HIT-R)            |  R  |
        |     |--------------------------------------------->|     |
        |     |<---------------------------------------------|     |
        +-----+             R2(R, I, HIT-R, HIT-I)           +-----+



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   This modification of HIP packets at a rendezvous server can be
   problematic because the HIP protocol uses integrity checks.  Because
   the I1 does not include HMAC or SIGNATURE parameters, these two end-
   to-end integrity checks are unaffected by the operation of rendezvous
   servers.

   The RVS SHOULD verify the checksum field of an I1 packet before doing
   any modifications.  After modification, it MUST recompute the
   checksum field using the updated HIP header, which possibly included
   new FROM and RVS_HMAC parameters, and a pseudo-header containing the
   updated source and destination IP addresses.  This enables the
   responder to validate the checksum of the I1 packet "as is", without
   having to parse any FROM parameters.

4.  Rendezvous Server Extensions

   The following sections describe extensions to the HIP registration
   protocol [I-D.koponen-hip-registration], allowing a HIP node to
   register with a rendezvous server for rendezvous service and notify
   the RVS aware of changes to its current location.  It also describes
   an extension to the HIP protocol [I-D.ietf-hip-base] itself, allowing
   establishment of HIP associations via one or more HIP rendezvous
   server(s).

4.1  RENDEZVOUS Registration Type

   This specification defines an additional registration for the HIP
   registration protocol [I-D.koponen-hip-registration] that allows
   registering with a rendezvous server for rendezvous service.

   Number   Registration Type
   ------   -----------------
   1        RENDEZVOUS


4.2  Parameter Formats and Processing

4.2.1  RVS_HMAC Parameter

   The RVS_HMAC is a non-critical parameter whose only difference with
   the HMAC parameter defined in [I-D.ietf-hip-base] is its "type" code.
   This change causes it to be located after the FROM parameter (as
   opposed to the HMAC):








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   Type        [ TBD by IANA (65500 = 2^16 - 2^5 - 2^2) ]
   Length      20
   HMAC        160 low order bits of a HMAC keyed with the
               appropriate HIP integrity key (HIP_lg or HIP_gl),
               established when rendezvous registration happened.
               This HMAC is computed over the HIP packet, excluding
               RVS_HMAC and any following parameters.  The
               "checksum" field MUST be set to zero and the HIP header
               length in the HIP common header MUST be calculated
               not to cover any excluded parameter when the
               "authenticator" field is calculated.

   To allow a rendezvous client and its RVS to verify the integrity of
   packets flowing between them, both SHOULD protect packets with an
   added RVS_HMAC parameter keyed with the HIP_lg or HIP_gl integrity
   key established while registration occurred.  A valid RVS_HMAC SHOULD
   be present on every packets flowing between a client and a server and
   MUST be present when a FROM parameters is processed.

4.2.2  FROM Parameter

     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
    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
    |             Type              |             Length            |
    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
    |                                                               |
    |                             Address                           |
    |                                                               |
    |                                                               |
    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

    Type        [ TBD by IANA (65498 = 2^16 - 2^5 - 2) ]
    Length      16
    Address     An IPv6 address or an IPv4-in-IPv6 format IPv4 address.

   A rendezvous server MUST add a FROM parameter containing the original
   source IP address of a HIP packet whenever the source IP address in
   the IP header is rewritten.  If one or more FROM parameters are
   already present, the new FROM parameter MUST be appended after the
   existing ones.

   Whenever an RVS inserts a FROM parameter, it MUST insert an RVS_HMAC
   protecting the packet integrity, especially the IP address included
   in the FROM parameter.






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4.2.3  VIA_RVS Parameter

      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
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |             Type              |             Length            |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |                                                               |
     |                            Address                            |
     |                                                               |
     |                                                               |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     .                               .                               .
     .                               .                               .
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |                                                               |
     |                            Address                            |
     |                                                               |
     |                                                               |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

     Type        [ TBD by IANA (65502 = 2^16 - 2^5 + 2) ]
     Length      Variable
     Address     An IPv6 address or an IPv4-in-IPv6 format IPv4 address

   After the responder receives a relayed I1 packet, it can begin to
   send HIP packets addressed to the initiator's IP address, without
   further assistance from an RVS.  For debugging purposes, it MAY
   include a subset of the IP addresses of its RVSs in some of these
   packets.  When a responder does so, it MUST append a newly created
   VIA_RVS parameter at the end of the HIP packet.  The main goal of
   using the VIA_RVS parameter is to allow operators to diagnose
   possible issues encountered while establishing a HIP association via
   an RVS.

4.3  Modified Packets Processing

   The following subsections describe the differences of processing of
   I1 and R1 while a rendezvous server is involved in the base exchange.

4.3.1  Processing Outgoing I1 Packets

   An initiator SHOULD NOT send an opportunistic I1 with a NULL
   destination HIT to an IP address which is known to be a rendezvous
   server address, unless it wants to establish a HIP association with
   the rendezvous server itself and does not know its HIT.

   When an RVS rewrites the source IP address of an I1 packet due to



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   egress filtering, it MUST add a FROM parameter to the I1 that
   contains the initiator's source IP address.  This FROM parameter MUST
   be protected by an RVS_HMAC keyed with the integrity key established
   at rendezvous registration.

4.3.2  Processing Incoming I1 packets

   When a rendezvous server receives an I1 whose destination HIT is not
   its own, it consults its registration database to find a registration
   for the rendezvous service established by the HIT owner.  If it finds
   an appropriate registration, it relays the packet to the registered
   IP address.  If it does not find an appropriate registration, it
   drops the packet.

   A rendezvous server SHOULD interpret any incoming opportunistic I1
   (i.e., an I1 with a NULL destination HIT) as an I1 addressed to
   itself and SHOULD NOT attempt to relay it to one of its clients.

   When a rendezvous client receives an I1, it MUST validate any present
   RVS_HMAC parameter.  If the RVS_HMAC cannot be verified, the packet
   SHOULD be dropped.  If the RVS_HMAC cannot be verified and a FROM
   parameter is present, the packet MUST be dropped.

   A rendezvous client acting as responder SHOULD drop opportunistic I1s
   that include a FROM parameter, because this indicates that the I1 has
   been relayed.

4.3.3  Processing Outgoing R1 Packets

   When a responder replies to an I1 relayed via an RVS, it MUST append
   to the regular R1 header a VIA_RVS parameter containing the IP
   addresses of the traversed RVS's.

4.3.4  Processing Incoming R1 packets

   The HIP base specification [I-D.ietf-hip-base] mandates that a system
   receiving an R1 MUST first check to see if it has sent an I1 to the
   originator of the R1 (i.e., it is in state I1-SENT).  When the R1 is
   replying to a relayed I1, this check SHOULD be based on HITs only.
   In case the IP addresses are also checked, then the source IP address
   MUST be checked against the IP address included in the VIA_RVS
   parameter.

5.  Security Considerations

   This section discusses the known threats introduced by these HIP
   extensions and implications on the overall security of HIP.  In
   particular, it argues that the extensions described in this document



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   do not introduce additional threats to the Host Identity Protocol.

   It is difficult to encompass the whole scope of threats introduced by
   rendezvous servers, because their presence has implications both at
   the IP and HIP layers.  In particular, these extensions might allow
   for redirection, amplification and reflection attacks at the IP
   layer, as well as attacks on the HIP layer itself, for example, man-
   in-the-middle attacks against the HIP base exchange.

   If an initiator has a priori knowledge of the responder's host
   identity when it first contacts it via an RVS, it has a means to
   verify the signatures in the HIP base exchange, which is known to be
   thus resilient to man-in-the-middle attacks.

   If an initiator does not have a priori knowledge of the responder's
   host identity (so-called "opportunistic initiators"), it is almost
   impossible to defend the HIP exchange against these attacks, because
   the public keys exchanged cannot be authenticated.  The only approach
   would be to mitigate hijacking threats on HIP state by requiring an
   R1 answering an opportunistic I1 to come from the same IP address
   that originally sent the I1.  This procedure retains a level of
   security which is equivalent to what exists in the Internet today.

   However, for reasons of simplicity, this specification does not allow
   to establish a HIP association via a rendezvous server in an
   opportunistic manner.

6.  IANA Considerations

   This section is to be interpreted according to [RFC2434].

   This document updates the IANA Registry for HIP Parameters Types by
   assigning new HIP Parameter Types values for the new HIP Parameters
   defined in Section 4.2:

   o  RVS_HMAC (defined in Section 4.2.1)

   o  FROM (defined in Section 4.2.2)

   o  VIA_RVS (defined in Section 4.2.3)


7.  Acknowledgments

   The following people have provided thoughtful and helpful discussions
   and/or suggestions that have improved this document: Marcus Brunner,
   Tom Henderson, Miika Komu, Mika Kousa, Pekka Nikander, Justino
   Santos, Simon Schuetz, Tim Shepard, Kristian Slavov, Martin



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   Stiemerling and Juergen Quittek.

   Julien Laganier and Lars Eggert are partly funded by Ambient
   Networks, a research project supported by the European Commission
   under its Sixth Framework Program.  The views and conclusions
   contained herein are those of the authors and should not be
   interpreted as necessarily representing the official policies or
   endorsements, either expressed or implied, of the Ambient Networks
   project or the European Commission.

8.  References

8.1  Normative References

   [I-D.ietf-hip-base]
              Moskowitz, R., "Host Identity Protocol",
              draft-ietf-hip-base-03 (work in progress), June 2005.

   [I-D.ietf-hip-dns]
              Nikander, P. and J. Laganier, "Host Identity Protocol
              (HIP) Domain Name System (DNS) Extensions",
              draft-ietf-hip-dns-01 (work in progress), February 2005.

   [I-D.koponen-hip-registration]
              Koponen, T. and L. Eggert, "Host Identity Protocol (HIP)
              Registration Extension", draft-koponen-hip-registration-00
              (work in progress), February 2005.

   [RFC1122]  Braden, R., "Requirements for Internet Hosts -
              Communication Layers", STD 3, RFC 1122, October 1989.

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

   [RFC2434]  Narten, T. and H. Alvestrand, "Guidelines for Writing an
              IANA Considerations Section in RFCs", BCP 26, RFC 2434,
              October 1998.

   [RFC3484]  Draves, R., "Default Address Selection for Internet
              Protocol version 6 (IPv6)", RFC 3484, February 2003.

8.2  Informative References

   [I-D.ietf-hip-arch]
              Moskowitz, R., "Host Identity Protocol Architecture",
              draft-ietf-hip-arch-02 (work in progress), January 2005.

   [I-D.ietf-hip-mm]



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              Nikander, P., "End-Host Mobility and Multi-Homing with
              Host Identity Protocol", draft-ietf-hip-mm-01 (work in
              progress), February 2005.

   [RFC1498]  Saltzer, J., "On the Naming and Binding of Network
              Destinations", RFC 1498, August 1993.

   [RFC2827]  Ferguson, P. and D. Senie, "Network Ingress Filtering:
              Defeating Denial of Service Attacks which employ IP Source
              Address Spoofing", BCP 38, RFC 2827, May 2000.

   [RFC3007]  Wellington, B., "Secure Domain Name System (DNS) Dynamic
              Update", RFC 3007, November 2000.

   [RFC3013]  Killalea, T., "Recommended Internet Service Provider
              Security Services and Procedures", BCP 46, RFC 3013,
              November 2000.


Authors' Addresses

   Julien Laganier
   DoCoMo Communications Laboratories Europe GmbH
   Landsberger Strasse 312
   Munich  80687
   Germany

   Phone: +49 89 56824 231
   Email: julien.ietf@laposte.net
   URI:   http://www.docomolab-euro.com/


   Lars Eggert
   NEC Network Laboratories
   Kurfuerstenanlage 36
   Heidelberg  69115
   Germany

   Phone: +49 6221 90511 43
   Fax:   +49 6221 90511 55
   Email: lars.eggert@netlab.nec.de
   URI:   http://www.netlab.nec.de/









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Internet-Draft          HIP Rendezvous Extension               July 2005


Appendix A.  Document Revision History

   +-----------+-------------------------------------------------------+
   | Revision  | Comments                                              |
   +-----------+-------------------------------------------------------+
   | 03        | Removed architectural discussions. Fixed some         |
   |           | requirements keywords.                                |
   | 02        | Removed multiple relaying techniques but simple I1    |
   |           | header rewriting. Updated new HIP parameters type     |
   |           | numbers (consistent with new layout and assigning     |
   |           | rules from draft-ietf-hip-base.) Updated IANA         |
   |           | Considerations.                                       |
   | 01        | Splitted out the registration sub-protocol. Simplify  |
   |           | typology of relaying techniques (keep only TUNNEL,    |
   |           | REWRITE, BIDIRECTIONAL). Rewrote IANA Considerations. |
   | 00        | Initial version as a HIP WG item.                     |
   +-----------+-------------------------------------------------------+


































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Internet-Draft          HIP Rendezvous Extension               July 2005


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