Chapter 14: Routing Policies; Routing Policies; Routing Policy File Syntax - Extreme Networks ExtremeWare XOS Guide Manual

14

Routing Policies

This chapter describes the following topics:
Routing Policies on page 279
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Routing Policy File Syntax on page 279
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Policy Match Conditions on page 280
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Policy Action Statements on page 283
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Applying Routing Policies on page 284
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Policy Examples on page 284
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Routing Policies
Routing policies are used to control the advertisement or recognition of routes using routing protocols,
such as Routing Information Protocol (RIP), Open Shortest Path First (OSPF), or Border Gateway
Protocol (BGP). Routing policies can be used to "hide" entire networks or to trust only specific sources
for routes or ranges of routes. The capabilities of routing policies are specific to the type of routing
protocol involved, but these policies are sometimes more efficient and easier to implement than access
lists.
Routing policies can also modify and filter routing information received and advertised by a switch.

Routing Policy File Syntax

The policy file contains one or more policy rule entries. Each routing policy entry consists of:
A policy entry rule name, unique within the same policy.
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Zero or one match type. If no type is specified, the match type is all, so all match conditions must be
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satisfied.
Zero or more match conditions. If no match condition is specified, then every routing entity matches.
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Zero or more actions. If no action is specified, the packet is permitted by default.
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Each policy entry in the file uses the following syntax:
entry <routingrulename>{
if <match-type> {
<match-conditions>;
} then {
<action>;
}
}
Here is an example of a policy entry:
entry ip_entry {
if match any {
nlri 10.203.134.0/24;
ExtremeWare XOS 11.3 Concepts Guide
279