INTERNET-DRAFT Alain Durand, SUN Microsystems NGTRANS WG George Tsirtsis, Flarion Technologies February 2001 IPv6 well known address for a 6to4 router 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 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. 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.