Internet Draft                                           RJ Atkinson
draft-irtf-rrg-ilnp-arp-02.txt                            Consultant
Expires:  16 OCT 2012                                      SN Bhatti
Category: Experimental                                 U. St Andrews
                                                      April 16, 2012

                        ARP Extension for ILNPv4
                     draft-irtf-rrg-ilnp-arp-02.txt

Status of this Memo

   Distribution of this memo is unlimited.

   Copyright (c) 2012 IETF Trust and the persons identified as the
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   Internet-Drafts are working documents of the Internet Engineering
   Task Force (IETF), its areas, and its working groups. Note that
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   Internet-Drafts are draft documents valid for a maximum of six
   months and may be updated, replaced, or obsoleted by other



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   documents at any time. It is inappropriate to use Internet-Drafts
   as reference material or to cite them other than as "work in
   progress."

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

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

   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, and 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
   controversial.

Abstract

   This document defines an Address Resolution Protocol (ARP)
   extension to support ILNP for IPv4 (ILNPv4). ILNP is is an
   experimental, evolutionary enhancement to IP. This document is a
   product of the IRTF Routing RG.

Table of Contents


     1. Introduction.............................
     2. ARP Extension for ILNPv4.................
     3. Security Considerations..................
     4. IANA Considerations......................
     5. References...............................

1. INTRODUCTION

   The Identifier Locator Network Protocol (ILNP) is an 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



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   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. This document discusses engineering and
   implementation details that are specific to ILNP for IPv4
   (ILNPv4). [ILNP-DNS] describes new Domain Name System (DNS)
   resource records used with ILNP. [ILNP-ICMPv4] defines the ICMP
   Locator Update message used with ILNPv4. [ILNP-v4opts] defines new
   IPv4 options for use with ILNPv4. Other documents describe ILNP
   for IPv6 (ILNPv6) [ILNP-ICMPv6] [ILNP-NONCE6].

1.2  Terminology

   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. [RFC-2119]

2.  ARP Extensions for ILNPv4

   ILNP for IPv4 (ILNPv4) is merely a different instantiation of the
   ILNP architecture, so it retains the crisp distinction between the
   Locator and the Identifier. As with ILNPv6, only the Locator
   values are used for routing and forwarding ILNPv4 packets
   [ILNP-ARCH]. As with ILNP for IPv6 (ILNPv6), when ILNPv4 is used
   for a network-layer session, the upper-layer protocols (e.g.
   TCP/UDP pseudo-header checksum, IPsec Security Association) bind
   only to the Identifiers, never to the Locators [ILNP-ENG].

   However, just as the packet format for IPv4 is different to IPv6,
   so the engineering details for ILNPv4 are different also. While
   ILNPv6 is carefully engineered to be fully backwards-compatible
   with IPv6 Neighbor Discovery, ILNPv4 relies upon an extended
   version of the Address Resolution Protocol (ARP) which is defined
   here. While ILNPv4 could have been engineered to avoid changes in
   ARP, that would have required that the ILNPv4 Locator (i.e. L32)
   have slightly different semantics, which was architecturally
   undesirable.

   The packet formats used are direct extensions of the existing
   widely deployed ARP Request (Opcode 1) and ARP Reply (Opcode 2)



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   packet formats. This design was chosen for practical engineering
   reasons (i.e. to maximise code reuse), rather than for maximum
   protocol design purity.

   We anticipate that ILNPv6 is much more likely to be widely
   implemented and deployed than ILNPv4. However, having a clear
   definition of ILNPv4 helps demonstrate the difference between
   architecture and engineering, and also demonstrates that the
   common ILNP architecture can be instantiated in different ways
   with different existing network-layer protocols.

2.1  ILNPv4 ARP Request Packet Format

   The ILNPv4 ARP Request (OP code XXX) is an extended version of the
   widely deployed ARP Request (Opcode 1). This extension permits the
   node's Identifier (I) values to be carried in the ARP message, in
   addition to the node's 32-bit Locator (L32) values [ILNP-DNS].


        0        7        15       23       31
        +--------+--------+--------+--------+
        |       HT        |        PT       |
        +--------+--------+--------+--------+
        |  HAL   |  PAL   |        OP       |
        +--------+--------+--------+--------+
        |         S_HA (bytes 0-3)          |
        +--------+--------+--------+--------+
        | S_HA (bytes 4-5)|S_L32 (bytes 0-1)|
        +--------+--------+--------+--------+
        |S_L32 (bytes 2-3)|S_I64 (bytes 0-1)|
        +--------+--------+--------+--------+
        |         S_I64 (bytes 2-5)         |
        +--------+--------+--------+--------+
        |S_ID (bytes 6-7) | T_HA (bytes 0-1)|
        +--------+--------+--------+--------+
        |         T_HA (bytes 3-5)          |
        +--------+--------+--------+--------+
        |         T_L32 (bytes 0-3)         |
        +--------+--------+--------+--------+
        |         T_I64 (bytes 0-3)         |
        +--------+--------+--------+--------+
        |         T_I64 (bytes 4-7)         |
        +--------+--------+--------+--------+

    Figure 2.1: ILNPv4 ARP Request packet format

   In the diagram of Fig 2.1, the fields are as follows:




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     HT      Hardware Type (same as for ARP; unchanged)
     PT      Protocol Type (same as for ARP; unchanged)
     HAL     Hardware Address Length (same as for ARP; unchanged)
     PAL     Protocol Address Length (uses new value 12)
     OP      Operation Code (uses new value XXX)
     S_HA    Sender Hardware Address (same as for ARP; unchanged)
     S_L32   Sender L32  (same as Sender IPv4 address for ARP)
     S_I64   Sender Identifier (8 bytes)
     T_HA    Target Hardware Address (same as for ARP; unchanged)
     T_L32   Target L32  (same as Target IPv4 address for ARP)
     T_I64   Target Identifier (8 bytes)

   The changed OP code indicates that this is ILNPv4 and not IPv4.
   The semantics and usage of the ILNPv4 ARP Request are identical to
   the existing ARP Request (Opcode 2), except that the ILNPv4 ARP
   Request is sent only by nodes that support ILNPv4.


2.2  ILNPv4 ARP Reply Packet Format

   The ILNPv4 ARP Reply (OP code YYY) is an extended version of the
   widely deployed ARP Reply (OP code 2). This extension permits the
   node's Identifier (I) values to be carried in the ARP message, in
   addition to the node's 32-bit Locator (L32) values [ILNP-DNS].

        0        7        15       23       31
        +--------+--------+--------+--------+
        |       HT        |        PT       |
        +--------+--------+--------+--------+
        |  HAL   |  PAL   |        OP       |
        +--------+--------+--------+--------+
        |         S_HA (bytes 0-3)          |
        +--------+--------+--------+--------+
        | S_HA (bytes 4-5)|S_L32 (bytes 0-1)|
        +--------+--------+--------+--------+
        |S_L32 (bytes 2-3)|S_I64 (bytes 0-1)|
        +--------+--------+--------+--------+
        |         S_I64 (bytes 2-5)         |
        +--------+--------+--------+--------+
        |S_ID (bytes 6-7) | T_HA (bytes 0-1)|
        +--------+--------+--------+--------+
        |         T_HA (bytes 3-5)          |
        +--------+--------+--------+--------+
        |         T_L32 (bytes 0-3)         |
        +--------+--------+--------+--------+
        |         T_I64 (bytes 0-3)         |
        +--------+--------+--------+--------+
        |         T_I64 (bytes 4-7)         |



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        +--------+--------+--------+--------+

    Figure 2.2: ILNPv4 ARP Reply packet format

   In the diagram of Fig 2.2, the fields are as follows:

     HT      Hardware Type (same as for ARP; unchanged)
     PT      Protocol Type (same as for ARP; unchanged)
     HAL     Hardware Address Length (same as for ARP; unchanged)
     PAL     Protocol Address Length (uses new value 12)
     OP      Operation Code (uses new value YYY)
     S_HA    Sender Hardware Address (same as for ARP; unchanged)
     S_L32   Sender L32  (same as Sender IPv4 address for ARP)
     S_I64   Sender Identifier (8 bytes)
     T_HA    Target Hardware Address (same as for ARP; unchanged)
     T_L32   Target L32  (same as Target IPv4 address for ARP)
     T_I64   Target Identifier (8 bytes)

   The changed OP code indicates that this is ILNPv4 and not IPv4.
   The semantics and usage of the ILNPv4 ARP Reply are identical to
   the existing ARP Reply (Opcode 2), except that the ILNPv4 ARP
   Reply is sent only by nodes that support ILNPv4.

2.3 Operation and Implementation of ARP for ILNPv4

   The operation of ARP for ILNPv4 is almost identical to that for
   IPv4. Essentially, the key difference is:

    a) where an IPv4 ARP Request would use IPv4 addresses, an
       ILNPv4 ARP Request MUST use:
        1. a 32-bit L value (_L32 suffixes in Figs 2.1 & 2.2)
        2. a 64-bit I value (_I64 suffixes in Figs 2.1 & Fig 2.2)

    b) where an IPv4 ARP Reply would use IPv4 addresses, an
       ILNPv4 ARP Reply MUST use:
        1. a 32-bit L value (_L32 suffixes in Figs 2.1 & 2.2)
        2. a 64-bit I value (_I64 suffixes in Figs 2.1 & Fig 2.2)

   As the OP codes XXX and YYY are distinct from ARP for IPv4, but
   the packet formats are Figs 2.1 and 2.2 are, effectively, extended
   versions of the corresponding ARP packets, it should be possible
   to implement this extension of ARP by extending existing ARP
   implementations rather than having to write an entirely new
   implementation for ILNPv4.


3.  SECURITY CONSIDERATIONS




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

   The existing widely deployed Address Resolution Protocol (ARP) for
   IP version 4 (IPv4) is a link-layer protocol, so it is not
   vulnerable to off-link attackers. In this way, it is a bit
   different than IPv6 Neighbor Discovery; IPv6 ND is a subset of the
   Internet Control Message Protocol (ICMP), which runs over the
   Internet Protocol version 6 (IPv6).

   However, ARP does not include any form of authentication, so
   current ARP deployments are vulnerable to a range of attacks from
   on-link nodes. For example, it is possible for one node on a link
   to forge an ARP packet claiming to be from another node, thereby
   "stealing" the other node's IPv4 address. [RFC-5227] both
   describes several of these risks and also describes some measures
   that an ARP implementation can use to reduce the chance of
   accidental IPv4 address misconfiguration and also to detect such
   misconfiguration if it should occur.

   This extension does not change the security risks that are
   inherent in using ARP.

   In situations where additional protection against on-link
   attackers is needed, for example within high-risk operational
   environments, the IEEE standards for link-layer security
   [IEEE-802.1-AE] SHOULD be implemented and deployed.


4.  IANA CONSIDERATIONS

   Subject to IESG Approval, consistent with the procedures of
   [RFC-5494], IANA is requested to assign new Operation Codes in
   the Address Resolution Protocol Parameters registry to the
   "ILNPv4 ARP Request" message (with value XXX above) and to the
   "ILNPv4 ARP Reply" message (with value YYY) above.

5.  REFERENCES

   This document has both Normative and Informational References.

5.1  Normative References

   [ILNP-ARCH]  R. Atkinson and S. Bhatti, "ILNP Architecture",
                draft-irtf-rrg-ilnp-arch, March 2012.



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   [ILNP-ENG]   R. Atkinson and S. Bhatti, "ILNP Engineering
                Considerations", draft-irtf-rrg-ilnp-eng, March 2012.

   [ILNP-DNS]   R. Atkinson and S. Bhatti, "DNS Resource Records
                for ILNP", draft-irtf-rrg-ilnp-dns, March 2012.

   [ILNP-ICMPv4] R. Atkinson and S. Bhatti, "ICMP Locator Update
               message for ILNPv4", draft-irtf-rrg-ilnp-icmpv4,
               March 2012.

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

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

   [RFC-5227]   S. Cheshire, "IPv4 Address Conflict Detection",
                RFC-5227, July 2008.

   [RFC-5494]   J. Arkko & C. Pignataro, "IANA Allocation Guidelines
                for the Address Resolution Protocol", RFC-5494,
                April 2009.

   [IEEE-802.1-AE] IEEE, "Media Access Control (MAC) Security",
                IEEE Standard 802.1 AE, 18 August 2006, IEEE,
                New York, NY, 10016, USA.

5.2  Informative References

   [ILNP-NONCE6] R. Atkinson and S. Bhatti, "ILNPv6 Nonce
                Destination Option", draft-irtf-rrg-ilnp-noncev6,
                March 2012.

   [ILNP-ICMPv6]  R. Atkinson and S. Bhatti, "ICMPv6 Locator
                Update Message for ILNPv6",
                draft-irtf-rrg-ilnp-icmpv6, March 2012.


ACKNOWLEDGEMENTS

   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



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   extremely helpful. We also wish to thank the anonymous reviewers
   of the various ILNP papers for their feedback.

RFC EDITOR NOTE

   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
   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.

AUTHOR'S ADDRESS

   RJ Atkinson
   Consultant
   San Jose, CA,
   95125 USA

   Email:     rja.lists@gmail.com


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

   Email: saleem@cs.st-andrews.ac.uk

   Expires: 16 OCT 2012













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