Cisco Configuration Example for Policy-Based Routing
Policy-based routing (PBR) is a feature of Cisco IOS that allows network administrators to modify the routing behavior of a router by creating routing policies. These policies are used to determine which incoming traffic is sent out which interface, as well as which kind of traffic is allowed in. PBR allows for greater flexibility and control over a network’s routing behavior, as it can be used to prioritize certain traffic, or to direct traffic to a specific interface or route.
This article will provide an example of how to configure PBR on a Cisco router. This example will set up a policy-based routing policy to prioritize traffic from the 192.168.1.0/24 subnet over traffic from the 10.10.10.0/24 subnet.
First, we need to configure the router to use PBR. This is done by entering the command “ip policy route-map” followed by a name for the policy. For this example, we’ll use “PBR_example” as the policy name.
Next, we need to configure the route-map. This is done using the “route-map” command. Within the route-map, we need to specify the match criteria for our policy. In this example, we’ll specify that we want to match traffic from the 192.168.1.0/24 subnet by entering the command “match ip address prefix-list 192.168.1.0/24”.
We then need to specify the action we want to take when the policy matches the traffic. In this example, we’ll specify that we want to set the next-hop of the matched traffic to be the interface with the IP address 10.1.1.2. This is done with the command “set ip next-hop 10.1.1.2”.
Finally, we need to apply the policy to an interface. This is done with the command “ip policy route-map PBR_example”. This will apply the policy to all traffic incoming on the interface.
Once the policy has been configured and applied, it will take effect immediately. Any traffic from the 192.168.1.0/24 subnet that is received on the specified interface will now be routed to the next-hop address of 10.1.1.2.
This example provides just one of the many ways that policy-based routing can be used to modify the routing behavior of a router. Network administrators have a great deal of flexibility when it comes to creating routing policies, so it is important to take the time to understand the features of PBR and how to configure them properly. With the right knowledge and configuration, PBR can be used to create powerful and effective routing policies that can help improve the performance and security of a network.