Technical Guide
How To Use Route Maps and Other Filters to Filter and Alter BGP and OSPF Routes
Introduction
ISPs transport large volumes of data. They often have to pay large amounts of money to transport their data through hired links, or through other providers' networks. Similarly, they can also charge money for transporting other ISPs' data through their network.
Where significant amounts of money are involved, there are typically complex negotiations involved, and agreements made that are bound by all sorts of rules and restrictions and guarantees.
Hence, ISPs need to be able to very precisely control which data gets sent and received on which links.This is achieved by having very precise control over the way the routing tables in their routers are built.
To that end, the BGP implementation in AlliedWare Plus includes a set of facilities for filtering routes, and for altering the attributes that are associated with certain routes in BGP update messages. The main purpose of this document is to give an overview of these features, and touches on how to configure them. One of the central route manipulation facilities is the route map.
Route maps can also be used for manipulating OSPF routes, so this document concludes by describing the use of route maps for OSPF.
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