Models of policy based routing (RFC1104)
Original Publication Date: 1989-Jun-01
Included in the Prior Art Database: 2000-Sep-12
Internet Society Requests For Comment (RFCs)
1. Status of this Memo
Network Working Group H-W. Braun
Request for Comments: 1104 Merit/NSFNET
Models of Policy Based Routing
1. Status of this Memo
The purpose of this RFC is to outline a variety of models for policy
based routing. The relative benefits of the different approaches are
reviewed. Discussions and comments are explicitly encouraged to move
toward the best policy based routing model that scales well within a
large internetworking environment.
Distribution of this memo is unlimited.
Specific thanks go to Yakov Rekhter (IBM Research), Milo Medin
(NASA), Susan Hares (Merit/NSFNET), Jessica Yu (Merit/NSFNET) and
Dave Katz (Merit/NSFNET) for extensively contributing to and
reviewing this document.
To evaluate the methods and models for policy based routing, it is
necessary to investigate the context into which the model is to be
used, as there are a variety of different methods to introduce
policies. Most frequently the following three models are referenced:
Policy based distribution of routing information
Policy based packet filtering/forwarding
Policy based dynamic allocation of network resources (e.g.,
bandwidth, buffers, etc.)
The relative properties of those methods need to be evaluated to find
their merits for a specific application. In some cases, more than
one method needs to be implemented.
While comparing different models for policy based routing, it is
important to realize that specific models have been designed to
satisfy a certain set of requirements. For different models these
requirements may or may not overlap. Even if they overlap, they may
have a different degree of granularity. In the first model, the
requirements can be formulated at the Administrative Domain or
network number level. In the second model, the requirements can be
formulated at the end system level or probably even at the level of
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 r...