Intra-Site Automatic Tunnel Addressing Protocol (ISATAP)

摘要

This document specifies an intra-site automatic tunneling protocol(ISATAP) for connecting IPv6 hosts and routers (nodes) withinpredominantly IPv4-based networks. This method is based on an IPv6aggregatable global unicast address format (described herein) thatembeds the IPv4 address of a node within the EUI-64 format interfaceidentifier. This document assumes that, during the IPv4 to IPv6 coexistenceand transition phase, many sites will deploy IPv6incrementally within their IPv4 interior routing domains; especiallythose sites which have large and complex pre-existing IPv4infrastructures. Within such sites, the address format and methodsdescribed in this document will enable IPv6 deployment for nodes thatdo not share a common link with an IPv6 gateway for their site.While other works in progress in the NGTRANS working group proposemechanisms for assigning globally-unique IPv6 address prefixes tosites and methods for inter-domain routing between such sites, theapproach outlined in this memo enables large-scale incrementaldeployment of IPv6 for nodes within a site's pre-existing IPv4infrastructure without incurring aggregation scaling issues at theborder gateways nor requiring site-wide deployment of special IPv4services such as multicast. The approach proposed by this documentsupports IPv6 routing within both the site-local and global IPv6routing domains as well as automatic IPv6 in IPv4 tunneling acrossportions of a site's IPv4 infrastructure which have no native IPv6support. Additionally, this approach supports automatic tunnelingwithin sites which use non globally-unique IPv4 address assignments,such as when Network Address Translation [NAT] is used.