RFC 1104 (rfc1104) - Page 2 of 10
Models of policy based routing
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RFC 1104 Models of Policy Based Routing June 1989 individual users. In the third model, the requirements need to be formulated at both the end system and local router level, as well as at the level of Routing Domains and Administrative Domains. Each of these models looks at the power of policy based routing in a different way. They may be implemented separately or in combination with other methods. The model to describe policy based dynamic allocation of network resources is orthogonal to the model of policy based distribution of routing information. However, in an actual implementation each of these models may interact. It is important to realize that the use of a policy based scheme for individual network applications requires that the actual effects as well as the interaction of multiple methods need to be determined ahead of time by policy. While uncontrolled dynamic routing and allocation of resources may have a better real time behavior, the use of policy based routing will provide a predictable, stable result based on the desires of the administrator. In a production network, it is imperative to provide continuously consistent and acceptable services. 4. Policy based distribution of routing information Goals: The goal of this model is to enforce certain flows by means of policy based distribution of routing information. This enforcement allows control over who can and who can not use specific network resources. Enforcement is done at the network or Administrative Domain (AD) level - macroscopic policies. Description: A good example of policy based routing based on the distribution of routing information is the NSFNET with its interfaces to mid- level networks [1], [2]. At the interface into the NSFNET, the routing information is authenticated and controlled by four means: 1. Routing peer authentication based on the source address. 2. Verification of the Administrative Domain identification (currently EGP Autonomous System numbers). 3. Verification of Internet network numbers which are advertised via the routing peer. Braun
