Internet DRAFT - draft-durand-ngtrans-6to4-well-known-address

draft-durand-ngtrans-6to4-well-known-address






INTERNET-DRAFT                            Alain Durand, SUN Microsystems
NGTRANS WG                         George Tsirtsis, Flarion Technologies
February 2001







                 IPv6 well known address for a 6to4 router


           <draft-durand-ngtrans-6to4-well-known-address-00.txt>



Status of this Memo


   This document is an Internet-Draft and is in full conformance with
   all provisions of Section 10 of RFC2026.


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


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   Distribution of this memo is unlimited.


   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 RFC2119.



1. Introduction


   A 6to4 [1] domain is derived from a single IPv4 address of a border
   6to4 router. Although it is possible to have several 6to4 exit router
   for outbound traffic, there can only be one 6to4 router for inbound
   traffic. This router is called the 6to4 designated router.


   Per the architecture of 6to4, it is trivial to find the IPv4 address
   of the 6to4 designated router. As 6to4 requires a global IPv4 address,
   this router is reachable from any host in the global IPv4 Internet.
   Inside the 6to4 domain, it may be the case that private address space
   is used, but the propagation of a specific route or a default route
   can maintain the reachability of the designated router in IPv4.


   Inside the 6to4 domain, the IPv6 routing system may propagate a default
   route to one of the 6to4 exit router, but there is no way to discover
   the IPv6 address of the 6to4 designated router. Outside the 6to4 domain,
   there is no way to address the 6to4 designated router in IPv6.


   This proposal aim at reserving a well known IPv6 address taken from the
   6to4 derived prefix for the 6to4 designated router.



2. Reserving a well known address


   SLAid = 0x0000 MUST be reserved as a virtual subnet for all 6to4 routers
   within a 6to4 domain.


   Per RFC2373 [2], section 2.6.1, a subnet router anycast address is
   defined with the 64 remaining bits set to zero. This will be the anycast
   address of any 6to4 router within that particular 6to4 domain.


   However, as anycast addresses can not be used as source address and
   this anycast address does not uniquely define the 6to4 designated router,
   we will go one step further and reserved the address made of:


     - the 16 bit TLA 0x2002 (the 6to4 TLA)
     - the 32 bit NLA xxxx:yyyy, where xxxx:yyyy is the IPv4 address of
       the 6to4 designated router
     - the 16 bit SLA 0x0000
     - the 64 bit Interface ID set to 0x0000000000000001


   as the reserved, well known, IPv6 address for the 6to4 designated router.


   All 6to4 routers within a 6to4 domain SHOULD be configured with the 6to4
   router anycast address.


   The 6to4 designated router MUST be configured with the well known
   IPv6 6to4 designated address.



3. Example


   If the IPv4 address of the designated 6to4 router is 201.202.203.204,
   then:
     - the 6to4 IPv6 prefix is 2002:C9CA:CBCC::/48
     - the reserved subnet for all 6to4 routers is 2002:C9CA:CBCC::/64
     - the anycast address for all the 6to4 router is 2002:C9CA:CBCC::0/128
     - the well know IPv6 address for the designated 6to4 router
       is 2002:C9CA:CBCC::1/128



4. Scaling issues


   The well known address for the 6to4 designated router has the same
   scaling issues as 6to4 itself, there can be several 6to4 outbound router,
   but only a single inbound router.
   
 
5. Security issues


   None.



6. Author's address


   Alain Durand
   SUN Microsystem, Inc.
   901 San Antonio road
   UMPK17-202
   PALO ALTO, CA 94303-4900
   USA
   EMail: Alain.Durand@sun.com
   
   George Tsirtsis
   Flarion Technologies
   G.Tsirtsis@Flarion.com
   gtsirt@hotmail.com



7. References


   [1] RFC3056, Connection of IPv6 Domains via IPv4 Clouds, Carpenter & Moore, 2001


   [2] RFC2373, IPv6 Addressing Architecture, Hinden & Deering, 1998



8. Copyright Notice


   Placeholder for ISOC copyright.