Policy requirements for inter Administrative Domain routing

The purpose of this memo is to focus discussion on particular problems in the Internet and possible methods of solution. No proposed solutions in this document are intended as standards for the Internet. Rather, it is hoped that a general consensus will emerge as to the appropriate solution to such problems, leading eventually to the development and adoption of standards. Distribution of this memo is unlimited. 2 ABSTRACT Efforts are now underway to develop a new generation of routing protocol that will allow each Administrative Domain (AD) in the growing Internet (and internets in general) to independently express and enforce policies regarding the flow of packets to, from, and through its resources. (FOOTNOTE 1: The material presented here incorporates discussions held with members of the IAB Autonomous Networks Research Group and the Open Routing Working Group.) This document articulates the requirements for policy based routing and should be used as input to the functional specification and evaluation of proposed protocols. Two critical assumptions will shape the type of routing mechanism that is devised: (1) the topological organization of ADs, and (2) the type and variability of policies expressed by ADs. After justifying our assumptions regarding AD topology we present a taxonomy, and specific examples, of policies that must be supported by a PR protocol. We conclude with a brief discussion of policy routing mechanisms proposed in previous RFCs (827, 1102, 1104, 1105). Future RFCs will elaborate on the architecture and protocols needed to support the requirements presented here. 3 BACKGROUND The Research Internet has evolved from a single backbone wide area network with many connected campus networks, to an internet with multiple crosscountry backbones, regional access networks, and a profusion of campus networks. (FOOTNOTE 2: The term Research Internet refers to a collection of government, university, and some private company, networks that are used by researchers to access shared Estrin [Page 1]