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ICMP Locator Update message for ILNPv4

The information below is for an old version of the document.
Document Type
This is an older version of an Internet-Draft that was ultimately published as RFC 6745.
Authors Ran Atkinson , SN Bhatti
Last updated 2012-05-24 (Latest revision 2012-05-17)
RFC stream Internet Research Task Force (IRTF)
Stream IRTF state (None)
Consensus boilerplate Unknown
Document shepherd (None)
IESG IESG state Became RFC 6745 (Experimental)
Telechat date (None)
Needs a YES.
Responsible AD Ralph Droms
IESG note
Send notices to,,,
Internet Draft                                           RJ Atkinson
draft-irtf-rrg-ilnp-icmpv4-03.txt                         Consultant
Expires:  17 Nov 2012                                      SN Bhatti
Category: Experimental                                   17 May 2012

                 ICMP Locator Update message for ILNPv4

Status of this Memo

   Distribution of this memo is unlimited.

   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
   Provisions Relating to IETF Documents
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   without warranty as described in the Simplified BSD License.

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

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

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

   Internet-Drafts 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

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   as reference material or to cite them other than as "work in

   The list of current Internet-Drafts can be accessed at

   The list of Internet-Draft Shadow Directories can be accessed at

   This document is not on the IETF standards-track and does not
   specify any level of standard. This document merely provides
   information for the Internet community.

   This document is part of the ILNP document set, which has had
   extensive review within the IRTF Routing Research Group.  ILNP is
   one of the recommendations made by the RG Chairs. Separately,
   various refereed research papers on ILNP have also been published
   during this decade. So the ideas contained herein have had much
   broader review than the IRTF Routing RG. The views in this
   document were considered controversial by the Routing RG, but the
   RG reached a consensus that the document still should be
   published. The Routing RG has had remarkably little consensus on
   anything, so virtually all Routing RG outputs are considered


   This note defines an experimental ICMP message type for IPv4 used
   with the Identifier-Locator Network Protocol (ILNP).  The
   Identifier-Locator Network Protocol (ILNP) is an experimental,
   evolutionary enhancement to IP.  The ICMP message defined herein
   is used to dynamically update Identifier/Locator bindings for an
   existing ILNP session.  This is a product of the IRTF Routing RG.

Table of Contents

     1. Introduction.............................2
     1.1  ILNP Document Roadmap..................3
     1.2  ICMPv4 Locator Update..................3
     1.3  Terminology............................3
     2. ICMP Locator Update message for ILNPv4...4
     3. Transport Protocol Effects...............5
     4. Implementation Considerations............6
     5. Backwards Compatibility..................6
     6. Security Considerations..................6
     7. IANA Considerations......................7
     8. References...............................7

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   The Identifier Locator Network Protocol (ILNP) is a proposal for
   evolving the Internet Architecture.  It differs from the current
   Internet Architecture primarily by deprecating the concept of an
   IP Address, and instead defining two new objects, each having
   crisp syntax and semantics.  The first new object is the Locator,
   a topology-dependent name for a subnetwork.  The other new object
   is the Identifier, which provides a topology-independent name for
   a node.

1.1  ILNP Document Roadmap

   The ILNP Architecture document [ILNP-ARCH] is the best place to
   start reading about ILNP.  ILNP has multiple instantiations.
   [ILNP-ENG] discusses engineering and implementation aspects
   common to all instances of ILNP.  [ILNP-v4OPTS] defines two new
   IPv4 options used with ILNPv4.  This document discusses a new
   ICMP for IPv4 message.  [ILNP-DNS] describes new Domain Name
   System (DNS) resource records used with ILNP.  Other documents
   describe ILNP for IPv6 (ILNPv6).

1.2  ICMPv4 Locator Update

   As described in [ILNP-ARCH] and [ILNP-ENG], an ILNP for IPv4
   (ILNPv4) node might need to inform correspondent ILNPv4 nodes of
   changes to the set of valid Locator values.  The new ICMPv4
   Locator Update message described in this document enables an
   ILNP-capable node to update its correspondents about the
   currently valid set of Locators valid to use in reaching the node
   sending this message [RFC2460] [RFC4443].

   This new ICMPv4 message MUST ONLY be used for ILNPv4 sessions.
   Authentication is always required, as described in the Security
   Considerations section later in this note.

   Some might consider any and all use of ICMP to be undesirable.
   In that context, please note that while this specification uses
   ICMP, on grounds that this is a control message, there is no
   architectural difference between using ICMP and using some
   different framing, for example UDP.

1.3  Terminology

   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL
   "OPTIONAL" in this document are to be interpreted as described

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   in RFC 2119. [RFC2119]

2.  ICMP Locator Update message for ILNPv4

   The ICMP for IPv4 message described in this section has ICMP Type
   XXX and is used ONLY with a current ILNPv4 session.  This message
   enables an ILNPv4 node to advertise changes to the active Locator
   set for the ILNPv4 node that originates this message to its
   unicast ILNP correspondent nodes.  It also enables those
   correspondents to acknowledge receipt of the advertisement.

   This particular ICMP for IPv4 message MUST ONLY be used with
   ILNPv4 communications sessions.  The Checksum field for this
   message is calculated identically as for any other IPv4 ICMP

    ICMP Locator Update message

       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      |     Code      |           Checksum            |
      |  Num of Locs  |   Operation   |           RESERVED            |
      /                       Locator [1]                             /
      |        Preference [1]         |           Lifetime [1]        |
      /                       Locator [2]                             /
      |        Preference [2]         |           Lifetime [2]        |

      ICMP Fields:

         Type                  XXX

         Code                  0

         Checksum              The  16-bit one's complement of the
                               one's complement sum of the ICMP
                               message, starting with the ICMP Type.
                               For computing the checksum, the
                               Checksum field is set to 0.

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         # Locators            The number of 32-bit Locator values
                               that are advertised in this message.

         Locator[i],           The 32-bit Locator values currently
          i = 1..Num of Locs   valid for the sending ILNPv4 node.

         Preference[i],        The preferability of each Locator[i],
          i = 1..Num of Locs   relative to other valid Locator[i]
                               values. The Preference numbers here
                               are identical, both in syntax and
                               semantics, to the Preference values
                               for L32 records that are specified by

         Lifetime[i]           The maximum number of seconds that this
          i = 1..Num of Locs   particular Locator may be considered
                               valid.  Normally, this is identical
                               to the DNS lifetime of the
                               corresponding L32 record, if one

          Operation            The value in this field indicates
                               whether this is a Locator Update
                               Advertisement (0x01) or a Locator
                               Update Acknowledgement (0x02).

          RESERVED             A field reserved for possible future
                               use.  At present, the sender MUST
                               initialise this field to zero.
                               Receivers should ignore this field at
                               present.  The field might be used for
                               some protocol function in future.

   The Operation field has value 1 (hexadecimal 0x01) for a Locator
   Update Advertisement.  The Operation field has value 2
   (hexadecimal 0x02) for a Locator Update Acknowledgement.  All
   other values of the Operation field are reserved for future use
   by future revisions of this specification.

   A node whose set of valid Locators has changed MUST send Locator
   Update Advertisement messages to each correspondent node for each
   active unicast ILNP session.  For unicast ILNP sessions, the
   receiver of a valid (i.e. authentication checks all passed,
   advertisement is received from a current correspondent node)
   Locator Update Advertisement addressed to the receiver MUST send
   a Locator Update Acknowledgement back to the sender of the
   Locator Update Advertisement.  The Acknowledgement message body

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   is identical to the received Advertisement message body, except
   for the Operation value.

   All ILNPv4 ICMP Locator Update messages MUST contain a valid
   ILNPv4 Identifier option and MUST contain an ILNPv4 Nonce Option.

   ILNPv4 ICMP Locator Update messages also MAY be protected using
   IP Security for ILNP [ILNP-ENG] [RFC4301].  Deployments in
   high-threat environments SHOULD also protect ILNPv4 ICMP Locator
   Update messages using IP Security.  While IPsec ESP can protect a
   payload, no form of IPsec ESP is able to protect an IPv4 option
   that appears prior to the ESP header.  Note that even when IP
   Security for ILNP is in use, the ILNPv4 Nonce Option still MUST
   be present.  This simplifies protocol processing, and it also
   means that a receiver can perform the inexpensive check of the
   Nonce value before performing any (potentially expensive)
   cryptographic calculation.

3.  Transport Protocol Effects

   This message has no impact on any transport protocol.

   The message may affect where packets for a given transport
   session are sent, but an ILNP design objective is to decouple
   transport-protocols from network-layer changes.

4. Implementation Considerations

   Implementers may use any internal implementation they wish,
   provided that the external appearance is the same as this
   implementation approach.

   To support ILNPv4, and to retain the incremental deployability
   and backwards compatibility needed, the network layer needs a
   mode bit in the Transport Control Block (or its equivalent) to
   track which IP sessions are using the classic IPv4 mode and which
   IP sessions are using ILNPv4 mode.

   Further, when supporting ILNPv4, nodes will need to support a
   Identifier Locator Communication Cache (ILCC) in the network
   layer as described in [ILNP-ENG].

   A node sending an ICMP Locator Update message MUST include all
   currently valid Locator values in that message.  A node receiving
   a valid ICMP Locator Update message MUST replace the previously
   current set of Locator values for that correspondent node in its
   own ILCC with the newly received set of Locator values.

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   Every implementation needs to support a large number of Locator
   values being sent or received in a single ICMP Locator Update
   message, because a multi-homed node or multi-homed site might
   have a large number of upstream links to different service
   providers, each with its own Locator value.

5.  Backwards Compatibility

   This IPv4 ICMP message uses the same checksum calculations as any
   other IPv4 ICMP message.

   When ILNPv4 is not in use, the receiving IPv4 mode MUST discard
   the ICMP Locator Update packet without processing the packet.


   Security considerations for the overall ILNP Architecture
   are described in [ILNP-ARCH].  Additional common security
   considerations are described in [ILNP-ENG].  This section
   describes security considerations specific to ILNPv4 topics
   discussed in this document.

   The ICMPv4 Locator Update message MUST ONLY be used for
   ILNPv4 sessions.

   The ILNPv4 Nonce Option [ILNP-v4OPTS] MUST be present in packets
   containing an ICMPv4 Locator Update message.  Further, the
   received Nonce Destination Option must contain the correct nonce
   value for the packet to be accepted by the recipient and then
   passed to the ICMPv4 protocol for processing. If either of these
   requirements are not met, the received packet MUST be discarded
   as a forgery, and a security event SHOULD be logged by the system
   receiving the non-authentic packet.

   Sessions operating in higher risk environments SHOULD use IP
   Security for ILNP [ILNP-ENG] [RFC4301] *in addition* to the
   ILNPv4 Nonce Option.  Use of IP Security for ILNP to protect a
   packet does NOT permit the packet to be sent without the Nonce

   Implementations need to support the case where a single ICMP
   Locator Update message contains a large number of Locator and
   Preference values and ought not develop a security fault
   (e.g. stack overflow) due to a received message containing more
   Locator values than expected.

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   If the ILNP Nonce value is predictable, then an off-path attacker
   might be able to forge data or control packets.  This risk also
   is mitigated by the existing common practice of IP Source Address
   filtering [RFC2827] [RFC3704].


   Subject to IESG Approval, following the procedures in [RFC2780],
   IANA is requested to assign a new ICMP Type number for this ICMP
   Locator Update message, replacing XXX above.

   The ICMP Locator Update message does not use the ICMP Extension
   Structure defined in [RFC4884].  At present, the only ICMP Code
   valid for this ICMP Type is zero (0), which means "No Code".


   This document has both Normative and Informational References.

8.1  Normative References

   [ILNP-ARCH]  R.J. Atkinson & S.N. Bhatti, "ILNP Architecture",
                draft-irtf-rrg-ilnp-arch, May 2012.

   [ILNP-DNS]   R.J. Atkinson & S.N. Bhatti, "DNS Resource Records
                for ILNP", draft-irtf-rrg-ilnp-dns, May 2012.

   [ILNP-ENG]   R.J. Atkinson & S.N. Bhatti, "ILNP Engineering
                Considerations", draft-irtf-rrg-ilnp-eng,
                May 2012.

   [ILNP-v4OPTS] R.J. Atkinson and S.N. Bhatti, "IPv4 Options for
                ILNPv4", draft-irtf-rrg-ilnp-v4opts,
                May 2012.

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

   [RFC2460]    S. Deering & R. Hinden, "Internet Protocol
                Version 6 Specification", RFC2460,
                December 1998.

   [RFC4443]   A. Conta, S. Deering, and M. Gupta, "Internet Control
               Message Protocol Version 6 (ICMPv6) Specification",
               RFC 4443, March 2006.

   [RFC4301]   S. Kent and K. Seo, "Security Architecture for

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               the Internet Protocol", RFC 4301, December 2005.

8.2  Informative References

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

   [RFC2780]  S. Bradner and V. Paxson,  "IANA Allocation
               Guidelines For Values In the Internet Protocol
               and Related Headers", RFC 2780, March 2000.

   [RFC3704]  F. Baker and P. Savola, "Ingress Filtering for
               Multihomed Networks", RFC 3704, March 2004.

   [RFC4884]  R. Bonica, D. Gan, D. Tappan, C. Pignataro,
               "Extended ICMP to Support Multi-Part Messages",
               RFC 4884, April 2007.


   Steve Blake, Stephane Bortzmeyer, Mohamed Boucadair, Noel
   Chiappa, Wes George, Steve Hailes, Joel Halpern, Mark Handley,
   Volker Hilt, Paul Jakma, Dae-Young Kim, Tony Li, Yakov Rehkter,
   Bruce Simpson, Robin Whittle and John Wroclawski (in alphabetical
   order) provided review and feedback on earlier versions of this
   document. Steve Blake provided an especially thorough review of
   an early version of the entire ILNP document set, which was
   extremely helpful. We also wish to thank the anonymous reviewers
   of the various ILNP papers for their feedback.

   Roy Arends provided expert guidance on technical and procedural
   aspects of DNS issues.


   This section is to be removed prior to publication.

   This document is written in English, not American.  So English
   spelling is used throughout, rather than American spelling.
   This is consistent with existing practice in several other RFCs,
   for example RFC-5887.

   This document tries to be very careful with history, in the
   interest of correctly crediting ideas to their earliest

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   identifiable author(s).  So in several places the first published
   RFC about a topic is cited rather than the most recent published
   RFC about that topic.


   RJ Atkinson
   San Jose, CA
   95125 USA


   SN Bhatti
   School of Computer Science
   University of St Andrews
   North Haugh, St Andrews
   Fife, Scotland
   KY16 9SX, UK


   Expires: 17 NOV 2012

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