[Docs] [txt|pdf] [Tracker] [WG] [Email] [Diff1] [Diff2] [Nits]

Versions: (draft-joshi-6man-neighbor-inform) 00

Network Working Group                                           S. Joshi
Internet-Draft                                                  S. Ooghe
Intended status: Standards Track                          Alcatel Lucent
Expires: September 23, 2010                               March 22, 2010


             Interface Identifier Assignment in IPv6 SLAAC
                   draft-ietf-6man-neighbor-inform-00

Abstract

   This document proposes an optional mechanism as part of IPv6
   Stateless Address Autoconfiguration for distribution of unique
   interface identifiers to IPv6 hosts on a link.  Hosts can then use
   these unique interface identifiers to generate unique autoconfigured
   link local and global unicast addresses.

   This mechanism is intended for use in networks where link layer
   identifiers are used for generating interface identifiers and where
   non unique link layer identifiers will result in duplicate link local
   addresses.  An example of such network is Ethernet Broadband access
   networks.


Status of this Memo

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

   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.

   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."

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

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

   This Internet-Draft will expire on September 23, 2010.

Copyright Notice



Joshi & Ooghe          Expires September 23, 2010               [Page 1]


Internet-Draft  Interface Identifier Assignment in SLAAC      March 2010


   Copyright (c) 2010 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 BSD License.


Table of Contents

   1.  Introduction . . . . . . . . . . . . . . . . . . . . . . . . .  3

   2.  Terminology  . . . . . . . . . . . . . . . . . . . . . . . . .  4
     2.1.  General  . . . . . . . . . . . . . . . . . . . . . . . . .  4
     2.2.  Requirements Language  . . . . . . . . . . . . . . . . . .  4

   3.  IPv6 Specification Dependency  . . . . . . . . . . . . . . . .  5

   4.  Neighbor Inform Message Format . . . . . . . . . . . . . . . .  6

   5.  Receiving Neighbor INFORM  . . . . . . . . . . . . . . . . . .  8
     5.1.  Validating of Neighbor Inform Messages . . . . . . . . . .  8
     5.2.  Node Specification . . . . . . . . . . . . . . . . . . . .  8
       5.2.1.  Host Configuration Variable  . . . . . . . . . . . . .  8
       5.2.2.  Processing Neighbor Inform . . . . . . . . . . . . . .  9

   6.  Delegating Interface Identifier  . . . . . . . . . . . . . . . 10
     6.1.  Delegating Node Specification  . . . . . . . . . . . . . . 10
       6.1.1.  Node Configuration Variable  . . . . . . . . . . . . . 10
       6.1.2.  Interface Initialization . . . . . . . . . . . . . . . 10
       6.1.3.  Sending Neighbor Inform  . . . . . . . . . . . . . . . 10

   7.  IANA Considerations  . . . . . . . . . . . . . . . . . . . . . 12

   8.  Security Considerations  . . . . . . . . . . . . . . . . . . . 13

   9.  Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 14

   10. References . . . . . . . . . . . . . . . . . . . . . . . . . . 15
     10.1. Normative References . . . . . . . . . . . . . . . . . . . 15
     10.2. Informative References . . . . . . . . . . . . . . . . . . 15




Joshi & Ooghe          Expires September 23, 2010               [Page 2]


Internet-Draft  Interface Identifier Assignment in SLAAC      March 2010


   Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 16


















































Joshi & Ooghe          Expires September 23, 2010               [Page 3]


Internet-Draft  Interface Identifier Assignment in SLAAC      March 2010


1.  Introduction

   This document introduces an optional mechanism for delegation of
   interface identifier as part of Stateless Address Autoconfiguration
   (SLAAC) [RFC4862].  A new optional message Neighbor Inform is
   introduced to Neighbor Discovery [RFC4861] to enable delegation of
   interface identifier.  A delegating node uses the message as part of
   SLAAC to delegate unique interface identifiers to hosts on a link.

   A typical case is an ethernet based broadband access network
   consisting of large number of Customer Premise Equiment (CPE) devices
   conneting to service providers core network.  In such a network it's
   quite likely that either a legitimate or a malicious CPE will have a
   duplicate MAC address and this would result in two or more hosts on
   the same link arriving at same EUI-64 based interface identifier as
   defined in [RFC2464].  Non-unique interface identifier will lead to
   duplicate link local and global unicast IPv6 addresses and as a
   result in Denial of Service for legitimate users.

   Deploying Network Address Translation is a possible solution to this
   problem, however it considerably increases the complexity and
   processing capability required in Broadband Access Nodes.  A protocol
   based solution is desirable as it is scalable and expandable.




























Joshi & Ooghe          Expires September 23, 2010               [Page 4]


Internet-Draft  Interface Identifier Assignment in SLAAC      March 2010


2.  Terminology

2.1.  General

      node - a device that implements IPv6.

      link - a communication facility or medium over which nodes can
      communicate at the link layer, i.e., the layer immediately below
      IP.  Examples are Ethernets (simple or bridged), PPP links or ATM
      networks as well as Internet-layer (or higher-layer) "tunnels",
      such as tunnels over IPv4 or IPv6 itself.

      neighbors - nodes attached to the same link.

      delegating node - a node that distributes interface identifiers to
      neighbors.

      host - any node that is not a router.

      proxy - a node that responds to Neighbor Discovery query messages
      on behalf of another node.

      tentative address - an address whose uniqueness on a link is being
      verified, prior to its assignment to an interface.  A tentative
      address is not considered assigned to an interface in the usual
      sense.  An interface discards received packets addressed to a
      tentative address, but accepts Neighbor Discovery packets related
      to Duplicate Address Detection for the tentative address.

      solicited-node multicast address - a multicast address to which
      Neighbor Solicitation messages are sent.  The algorithm for
      computing the address is given in [RFC4291].

2.2.  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].













Joshi & Ooghe          Expires September 23, 2010               [Page 5]


Internet-Draft  Interface Identifier Assignment in SLAAC      March 2010


3.  IPv6 Specification Dependency

   This document describes a new neighbor discovery message and the
   processing associated with this message.  This document should be
   read in conjunction with IPv6 Neighbor Discovery [RFC4861] and IPv6
   Stateless Address Autoconfiguration [RFC4862].













































Joshi & Ooghe          Expires September 23, 2010               [Page 6]


Internet-Draft  Interface Identifier Assignment in SLAAC      March 2010


4.  Neighbor Inform Message Format

   A delegating node sends Neighbor Inform message in response to
   Neighbor Solicatation message sent as part of Duplicate Address
   detection.


   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             |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |S|R|P|                       Reserved                          |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |   Options ...
   +-+-+-+-+-+-+-+-+-+-+-+-



   Figure 1: Neighbor Inform Message Format

   IP Fields:

      Source Address - An address assigned to the interface from which
      the inform is sent.

      Destination Address - The solicited-node multicast address.

      Hop Limit - 255

      ICMP Fields:

      Type - 155

      Code 0 - Reconfigure

      Checksum - ICMP checksum.

      S - Solicited flag.  When set, the S-bit indicates that inform was
      sent in response to a message from Destination address.

      R - Router flag.  When set, the R-bit indicates that the sender is
      a router.

      P - Proxy flag.  When set, the P-bit indicates that the sender is
      a Neighbor Discovery Proxy.





Joshi & Ooghe          Expires September 23, 2010               [Page 7]


Internet-Draft  Interface Identifier Assignment in SLAAC      March 2010


      Reserved- 29-bit unused field.  It MUST be initialized to zero by
      the sender and MUST be ignored by the receiver.



      Possible options:

      Identifier- Identifier is ICMP code of message that caused this
      INFORM (e.g. 135 - Solicit)

      Target address - The IP address of the target of the solicitation.
      Option must be included if ICMP Code is 0 and Identifier is
      SOLICIT.

      Interface-ID - Alternative interface ID to be used when
      reconfiguring link local IPv6 address.

   Future versions of this protocol may define new option types.
   Receivers MUST silently ignore any options they do not recognize and
   continue processing the message.































Joshi & Ooghe          Expires September 23, 2010               [Page 8]


Internet-Draft  Interface Identifier Assignment in SLAAC      March 2010


5.  Receiving Neighbor INFORM

5.1.  Validating of Neighbor Inform Messages

   A node MUST silently discard any received Neighbor Inform messages
   that do not satisfy all of the following validity checks:

      - The IP Hop Limit field has a value of 255, i.e., the packet
      could not possibly have been forwarded by a router.

      - ICMP Checksum is valid.

      - ICMP Code is 0.

      - ICMP length (derived from the IP length) is 24 or more octets.

      - Target Address is not solicited node multicast address of
      tentative address assigned to receiving interface.

      - If the IP Destination Address is a multicast address the
      Solicited flag is zero.

      - All included options have a length that is greater than zero.

   The contents of the Reserved field, and of any unrecognized options,
   MUST be ignored.  Future, backward-compatible changes to the protocol
   may specify the contents of the Reserved field or add new options;
   backward-incompatible changes may use different Code values.  The
   contents of any defined options that are not specified to be used
   with Neighbor Inform messages MUST be ignored and the packet
   processed as normal.  A Neighbor Inform that passes the validity
   checks is called a "valid inform".

5.2.  Node Specification

5.2.1.  Host Configuration Variable

   A node MUST allow for the following conceptual variables to be
   configured by system management.  The specific variable names are
   used for demonstration purposes only, and an implementation is not
   required to have them, so long as its external behavior is consistent
   with that described in this document.  Default values are specified
   to simplify configuration in common cases.

   For each interface:

   NbrRcvInform




Joshi & Ooghe          Expires September 23, 2010               [Page 9]


Internet-Draft  Interface Identifier Assignment in SLAAC      March 2010


   A flag indicating whether processing of received Neighbor Inform
   messages is enabled on this interface.  Enabling would indicate that
   node will accept delegated interface identifier for the interface.

   Default Value :FALSE

5.2.2.  Processing Neighbor Inform

   On receipt of a valid Neighbor Inform message on an interface, node
   behavior depends on whether target address option in message matches
   a tentative address or an address assigned to the interface.

   If the target address is not tentative (i.e., it is assigned to the
   receiving interface), the Neighbor Inform message is silently
   discarded by the node.

   If the node has not transmitted a Neighbor Solicit with target
   address.  This could be the case where two nodes with same tentative
   address are attempting DAD and delegating node has responded to other
   nodes Solicit request.  The Neighbor Inform message is silently
   discarded by the node and node proceeds with DAD for tentative
   address.

   If the target address option in the Inform message matches tentative
   address of the received interface then the tentative address is
   determined as duplicate.

   A tentative address that is determined to be duplicate SHOULD NOT be
   assigned to the interface, and the node SHOULD log a system
   management error.

   If Interface-ID option is present in the Inform message, node MUST
   use the interface identifier provided to regenerate an IPv6 link
   local or global unicast address and reinitiate Duplicate Address
   Detection (DAD).
















Joshi & Ooghe          Expires September 23, 2010              [Page 10]


Internet-Draft  Interface Identifier Assignment in SLAAC      March 2010


6.  Delegating Interface Identifier

6.1.  Delegating Node Specification

6.1.1.  Node Configuration Variable

   A node MUST allow for the following conceptual variables to be
   configured by system management.  The specific variable names are
   used for demonstration purposes only, and an implementation is not
   required to have them, so long as its external behavior is consistent
   with that described in this document.  Default values are specified
   to simplify configuration in common cases.

   For each interface:

   NbrDelegationEnable

   A flag indicating whether sending of Neighbor Inform messages is
   enabled on this interface.  Setting the flag to true would indicate
   that node will act as a delegating node on that interface.

   Default Value :FALSE

6.1.2.  Interface Initialization

   The node joines all-nodes multicast address on interfaces enabled for
   delegation.

6.1.3.  Sending Neighbor Inform

   A delegating node sends a Neighbor Inform in response to a Neighbor
   Soliciation received as part of Duplicate Addresses Detection
   initiated by an IPv6 host.  Neighbor Solicit messages sent as part of
   DAD have source address set as unspecified address.

   The Target Address of the Inform is copied from the Target Address of
   the soliciation.  The node populates the Interface-ID of the inform
   either from a database or using a dynamic algorithm.  The node may
   use additional information from received Solicit message e.g. link
   local address,vlan or physical interface (e.g.  DSL) to arrive at a
   unique Interface-ID to be delegated.

   Furthermore, if a node is a router, it MUST set the Router flag to
   one;otherwise it must set the flag to zero

   If a node is a proxy, it MUST set the proxy flag to one;otherwise it
   must set the flag to zero




Joshi & Ooghe          Expires September 23, 2010              [Page 11]


Internet-Draft  Interface Identifier Assignment in SLAAC      March 2010


   The node MUST set the solicited flag to one and multicast the inform
   to all-nodes address.

















































Joshi & Ooghe          Expires September 23, 2010              [Page 12]


Internet-Draft  Interface Identifier Assignment in SLAAC      March 2010


7.  IANA Considerations

   IANA is requested to assign a new ICMPv6 Type (155) for NEIGHBOR
   INFORM message.















































Joshi & Ooghe          Expires September 23, 2010              [Page 13]


Internet-Draft  Interface Identifier Assignment in SLAAC      March 2010


8.  Security Considerations

   Unsecured Neighbor Discovery has a number of security issues, which
   are discussed in detail in [RFC3756].  Security mechanisms to protect
   Neighbor Discovery are described in [RFC3971].














































Joshi & Ooghe          Expires September 23, 2010              [Page 14]


Internet-Draft  Interface Identifier Assignment in SLAAC      March 2010


9.  Acknowledgements

   This document liberally borrows text from RFC4862 and RFC4861.
















































Joshi & Ooghe          Expires September 23, 2010              [Page 15]


Internet-Draft  Interface Identifier Assignment in SLAAC      March 2010


10.  References

10.1.  Normative References

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

   [RFC4291]  Hinden, R. and S. Deering, "IP Version 6 Addressing
              Architecture", RFC 4291, February 2006.

   [RFC4861]  Narten, T., Nordmark, E., Simpson, W., and H. Soliman,
              "Neighbor Discovery for IP version 6 (IPv6)", RFC 4861,
              September 2007.

   [RFC4862]  Thomson, S., Narten, T., and T. Jinmei, "IPv6 Stateless
              Address Autoconfiguration", RFC 4862, September 2007.

10.2.  Informative References

   [RFC2464]  Crawford, M., "Transmission of IPv6 Packets over Ethernet
              Networks", RFC 2464, December 1998.

   [RFC3756]  Nikander, P., Kempf, J., and E. Nordmark, "IPv6 Neighbor
              Discovery (ND) Trust Models and Threats", RFC 3756,
              May 2004.

   [RFC3971]  Arkko, J., Kempf, J., Zill, B., and P. Nikander, "SEcure
              Neighbor Discovery (SEND)", RFC 3971, March 2005.























Joshi & Ooghe          Expires September 23, 2010              [Page 16]


Internet-Draft  Interface Identifier Assignment in SLAAC      March 2010


Authors' Addresses

   Shrinivas Joshi
   Alcatel Lucent
   RR Towers IV, Thiruvika Industrial Estate, Guindy
   Chennai, Tamil Nadu  600032
   India

   Phone: +91-44-3099-8165
   Email: shrinivas_ashok.joshi@alcatel-lucent.com


   Sven Ooghe
   Alcatel Lucent
   Copernicuslaan 50
   Antwerp  2018
   Belgium

   Phone: +32-32404226
   Email: sven.ooghe@alcatel-lucent.com































Joshi & Ooghe          Expires September 23, 2010              [Page 17]


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