RFC 1787 (rfc1787) - Page 1 of 8

Routing in a Multi-provider Internet

Network Working Group                                         Y. Rekhter
Request for Comments: 1787        T.J. Watson Research Center, IBM Corp.
Category: Informational                                       April 1995


                  Routing in a Multi-provider Internet

Status of this Memo

   This memo provides information for the Internet community.  This memo
   does not specify an Internet standard of any kind.  Distribution of
   this memo is unlimited.

Abstract

   This document was prepared by the author on behalf of the Internet
   Architecture Board (IAB). It is offered by the IAB to stimulate
   discussion.

   Over the past few years the Internet has undergone significant
   changes.  Among them is the emergence of multiple Network Service
   Providers, where resources that provide Internet-wide IP connectivity
   (routers, links) are controlled by different organizations.  This
   document presents some of the issues related to network layer routing
   in a multi-provider Internet, and specifically to the unicast
   routing.

1. Network Service Providers vs Network Service Subscribers

   Within the current routing paradigm the service offered by a provider
   at the network layer (IP) is the set of destinations (hosts) that can
   be reached through the provider. Once a subscriber establishes direct
   connectivity to a provider, the subscriber can in principle reach all
   the destinations reachable through the provider. Since the value of
   the Internet-wide connectivity service offered by a provider
   increases with the number of destinations reachable through the
   provider, providers are motivated to interconnect with each other.

   In principle a provider need not offer the same service (in terms of
   the set of destinations) to all of its subscribers -- for some of the
   subscribers the provider may restrict the services to a subset of the
   destinations reachable through the provider. In fact, for certain
   types of subscribers constrained connectivity could be seen as part
   of the service offered by a provider.

   In a multi-provider environment individual providers may be driven by
   diverse and sometimes even conflicting goals and objectives. Some of
   the providers exist to provide connectivity to only a specific group



Rekhter