Chapter 11. Defining and Implementing Routing Policies

This chapter aims to give you an understanding of routing policies and how they are implemented on the Juniper Networks M-Series routers. It begins by outlining what a routing policy is and where routing policy can be found in today's Internet. Routing policy specification language (RPSL) is then discussed with examples of RPSL objects and what they mean. After this theoretical introduction on routing policy, the application of policy in the JUNOS environment is reviewed along with a routing-policy design model called the designing, implementing, executing, and testing (DIET) policy method. The chapter ends with a look at some more advanced topics, such as route filtering, BGP regular expressions, and community attribute matching.

The chapter gives the beginner a firm foundation for grasping the fundamentals of routing-policy creation, while providing more in-depth knowledge for the advanced user . This knowledge can then be used to ensure that the routes coming into and out of your ISP or corporate network conform to predefined rules for the exchange of these routes at peering points. The methodology and ideas in this chapter do not pertain solely to Juniper Networks routers. No matter what types of routers are deployed in your network, you will still need to configure some sort of policy, and for this, the concepts presented here are still valid.