CHAPTER
25-1
Software Configuration Guide—Release 12.2(25)SG
OL-7659-03
25
Configuring Policy-Based Routing
This chapter describes the tasks for configuring policy-based routing (PBR) on a router and includes
these major sections:
Overview of Policy-Based Routing, page 25-1
Policy-Based Routing Configuration Task List, page 25-3
Policy-Based Routing Configuration Examples, page 25-5
Note For a complete description of the PBR commands in this chapter, refer to the Cisco IOS Quality of
Service Solutions Command Reference at:
http://www.cisco.com/univercd/cc/td/doc/product/software/ios123/123tcr/123tqr/
Note To identify the hardware platform or software image in formation associated with a feature, use t he
Feature Navigator on Cisco.com to search for information about the feature or refer to the software
release notes for a specific release.

Overview of Policy-Based Routing

This section contains the following subsections:
Understanding PBR, page 25-2
Understanding PBR Flow Switching, page 25-2
Using Policy-Based Routing, page 25-2
PBR gives you a flexible means of routing packets by allowing you to configure a defined policy for
traffic flows, lessening reliance on routes derived from routing protocols. To this end, PBR gives you
more control over routing by extending and complementing the existing mechanisms provided by ro uting
protocols. PBR allows you to specify a path for certain traffic, such as priority traffic over a high-cost
link.
You can set up PBR as a way to route packets based on configured policies. For example, you can
implement routing policies to allow or deny paths based on the identity of a particular end system, an
application protocol, or the size of packets.