Policy routing in Internet protocols (RFC1102)
Original Publication Date: 1989-May-01
Included in the Prior Art Database: 2019-Feb-11
Internet Society Requests For Comment (RFCs)
The purpose of this RFC 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.
Network Working Group D. Clark Request for Comments: 1102 M.I.T. Laboratory for Computer Science May 1989
Policy Routing in Internet Protocols
1. Status of this Memo
The purpose of this RFC 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. Distribution of this memo is unlimited.
An integral component of the Internet protocols is the routing function, which determines the series of networks and gateways a packet will traverse in passing from the source to the destination. Although there have been a number of routing protocols used in the Internet, they share the idea that one route should be selected out of all available routes based on minimizing some measure of the route, such as delay. Recently, it has become important to select routes in order to restrict the use of network resources to certain classes of customers. These considerations, which are usually described as resource policies, are poorly enforced by the existing technology in the Internet. This document proposes an approach to integrating policy controls into the Internet.
I assume that the resources of the Internet: networks, links, and gateways, are partitioned into Administrative Regions or ARs. Each AR is governed by a somewhat autonomous administration, with distinct goals as to the class of customers it intends to serve, the qualities of service it intends to deliver, and the means for recovering its cost. To construct a route across the Internet, a sequence of ARs must be selected that collectively supply a path from the source to the destination. This sequence of ARs will be called a Policy Route, or PR. Each AR through which a Policy Route passes will be concerned that the PR has been properly constructed. To this end, each AR may wish to insure that the user of the PR is authorized, the requested quality of service is supported, and that the cost of the service can be recovered.
In the abstract, a Policy Route is a series of ARs, which are assumed to be named with globally distinct identifiers. (The requirement for global names for ARs suggests that the name space of ARs is flat. That simplifying assumption is made in this RFC, but it should be possible to extend the scheme described here to permit nesting of ARs
Clark [Page 1]
RFC 1102 Policy Routing in Internet Protocols May 1989
to reduce the amount of global information. The problem of adding structure to the space of ARs is an exercise for later study.) Before a PR can be used, however, it must be reduced to more concrete terms; a series of gateways which connect the sequence of ARs. These gateways will be called Policy Gateways.
Presently, the closest mechanism to policy routing in the Internet is EGP, the Exterior Gateway Protocol. EGP was constructed to permit regions of the Internet to communicate reachability information, even though they did not totally share trust....