Network Working Group                                          C. Donley
Internet-Draft                                             C. Grundemann
Intended status: Informational                                 CableLabs
Expires: March 10, 2013                                September 6, 2012


               Customer Edge Router Identification Option
                   draft-donley-dhc-cer-id-option-01

Abstract

   Several addressing mechanisms supporting DHCPv6 Prefix Delegation in
   home networks require identification of the customer edge router
   (CER) as the demarcation between the customer network and the service
   provider network.  This document reserves a DHCPv6 option to identify
   the CER.

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Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . . . 3
     1.1.  Requirements Language . . . . . . . . . . . . . . . . . . . 3
   2.  CER Identification Option . . . . . . . . . . . . . . . . . . . 3
   3.  IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 4
   4.  Security Considerations . . . . . . . . . . . . . . . . . . . . 4
   5.  Acknowledgements  . . . . . . . . . . . . . . . . . . . . . . . 4
   6.  References  . . . . . . . . . . . . . . . . . . . . . . . . . . 4
     6.1.  Normative References  . . . . . . . . . . . . . . . . . . . 4
     6.2.  Informative References  . . . . . . . . . . . . . . . . . . 4
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . . . 5







































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1.  Introduction

   Several addressing mechanisms supporting DHCPv6 Prefix Delegation in
   home networks such as [I-D.gmann-homenet-relay-autoconf] require
   identification of the customer edge router as the demarcation between
   the customer network and the service provider network.  For prefix
   delegation purposes, it is desirable for other routers within the
   home to know which device is the CER so that the customer nome
   network only requests a single prefix from the ISP DHCPv6 server, and
   efficiently distributes this prefix within the home.  This document
   reserves a DHCPv6 option to be used to identify the CER.

1.1.  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].


2.  CER Identification Option

   A CER sets the CER_ID to the IPv6 address of its LAN interface.  If
   it has more than one LAN IPv6 address, it selects one of its LAN or
   loopback IPv6 addresses to be used in the CER_ID.  An ISP server does
   not respond with the CER_ID or sets the CER_ID to ::.  Such a
   response or lack of response indicates to the DHCPv6 client that it
   is the CER.

   The format of the CER Identification option is:

   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
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |       option-code             |       option-len              |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                                                               |
   |                       CER_ID                                  |
   |                                                               |
   |                                                               |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
           option-code     OPTION_CER_ID (TBD).
           option-len      16
           CER_ID value    IPv6 address of CER or ::

   Figure 1.

   A DHCPv6 client SHOULD include the CER Identification option code in
   an Option Request option [RFC3315] in its DHCP Solicit messages.  The



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   DHCPv6 server MAY include the CER Identification option in any
   response it sends to a client that has included the CER
   Identification option code in an Option Request option.  The CER
   Identification option is sent in the main body of the message to
   client, not as a sub-option in, e.g., an IA_NA, IA_TA
   [RFC3315]option.  When sending the CER Identification option, the
   DHCPv6 server MUST set the CER_ID value to either one of its IPv6
   addresses or ::.  If a device does not receive the CER Identification
   Option or receives a CER ID of :: from the DHCPv6 server, it MUST
   include one of its Globally Unique IPv6 address(es) in the CER_ID
   value in response to DHCPv6 messages received by its DHCPv6 server
   that contains the CER Identification option code in an Option Request
   option.  If the device has only one LAN interface, it SHOULD use its
   LAN IPv6 address as the CER_ID value.  If the device has more than
   one LAN interface, it SHOULD use the lowest Globally Unique address
   not assigned to its WAN interface.


3.  IANA Considerations

   IANA is requested to assign an option code from the "DHCP Option
   Codes" Registry for OPTION_CER_ID.


4.  Security Considerations

   TBD


5.  Acknowledgements


6.  References

6.1.  Normative References

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

   [RFC3315]  Droms, R., Bound, J., Volz, B., Lemon, T., Perkins, C.,
              and M. Carney, "Dynamic Host Configuration Protocol for
              IPv6 (DHCPv6)", RFC 3315, July 2003.

6.2.  Informative References

   [I-D.gmann-homenet-relay-autoconf]
              Grundemann, C. and C. Donley, "Home Network
              Autoconfiguration via DHCPv6 Relay",



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              draft-gmann-homenet-relay-autoconf-01 (work in progress),
              March 2012.


Authors' Addresses

   Chris Donley
   CableLabs
   858 Coal Creek Cir.
   Louisville, CO  80027
   US

   Email: c.donley@cablelabs.com


   Chris Grundemann
   CableLabs
   858 Coal Creek Cir.
   Louisville, CO  80027
   US

   Email: c.grundemann@cablelabs.com





























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