What is Policy-Based Routing and why to use it?
Policy-based routing (PBR) is a technique used to make routing decisions based on policies set by the network administrator. When a router receives a packet it normally decides where to forward it based on the destination address in the packet, which is then used to look up an entry in a routing table. However, in some cases, there may be a need to forward the packet based on other criteria. For example, a network administrator might want to forward a packet based on the source address, not the destination address.
In the network below there are a total of four routers, two end-user computers and a server. In real world deployments a network could have dozens or hundreds of routers or devices depending on the scale of the network. Static routes are deployed to establish full network connectivity between the end-user computers and the server. Additionally route-maps and route policies are deployed to route PC1 over the network path of R2 to R1 to R4 and PC2 over the network path of R2 to R3 to R4 to reach the remote server.
Verify the configuration
Now that the configuration is finished lets verify our routes. Using the show ip route and traceroute commands you can verify the expected routes in the routing table and verify the network path (route) used. Use the ping command to verify connectivity.
