RFC 2185 (rfc2185) - Page 2 of 13
Routing Aspects of IPv6 Transition
Alternative Format: Original Text Document
RFC 2185 Routing Aspects Of IPv6 Transition September 1997 neighbors - nodes attached to the same link. routing domain - a collection of routers which coordinate routing knowledge using a single routing protocol. routing region (or just "region") - a collection of routers interconnected by a single internet protocol (e.g. IPv6) and coordinating their routing knowledge using routing protocols from a single internet protocol stack. A routing region may be a superset of a routing domain. tunneling - encapsulation of protocol A within protocol B, such that A treats B as though it were a datalink layer. reachability information - information describing the set of reachable destinations that can be used for packet forwarding decisions. routing information - same as reachability information. address prefix - the high-order bits in an address. routing prefix - address prefix that expresses destinations which have addresses with the matching address prefixes. It is used by routers to advertise what systems they are capable of reaching. route leaking - advertisement of network layer reachability information across routing region boundaries. 2. ISSUES AND OUTLINE This document gives an overview of the routing aspects of IPv4 to IPv6 transition. The approach outlined here is designed to be compatible with the existing mechanisms for IPv6 transition [1]. During an extended IPv4-to-IPv6 transition period, IPv6-based systems must coexist with the installed base of IPv4 systems. In such a dual internetworking protocol environment, both IPv4 and IPv6 routing infrastructure will be present. Initially, deployed IPv6-capable domains might not be globally interconnected via IPv6-capable internet infrastructure and therefore may need to communicate across IPv4-only routing regions. In order to achieve dynamic routing in such a mixed environment, there need to be mechanisms to globally distribute IPv6 network layer reachability information between dispersed IPv6 routing regions. The same techniques can be used in later stages of IPv4-to-IPv6 transition to route IPv4 packets between isolated IPv4-only routing region over IPv6 infrastructure. Callon & Haskin Informational
