What is Policy-Based Routing?
Policy-based routing is used to change the path that a flow with a specific destination address takes out of the router. In the example below, the normal flow of VoIP traffic between the 2811 router and the 1841 router is shown:
![](/static/d4a33c2e22338b054e006336d9edf443/6aa1e/What-is-Policy-Based-Routing.png)
In the following example, PBR will be applied to the 2811 router on the Fas0/0 interface, so that traffic flows through the VLAN 1 interface rather than Fa0/1. The flow will also enter the 1841 router from the VLAN 1 interface instead of Fa1. This can be visualized using NetFlow displays for the 2811 and 1841 routers.
![](/static/7dcf0fcfe2811e286474dab88965e907/6aa1e/What-is-Policy-Based-Routing2.png)
NOTE: The policy is applied at the ingress interface of the receiving router.