Cisco Policy Based Routing provides a flexible mechanism for network administrators to customize the operation of the routing table and the flow of traffic within their networks. Policy Based Routing (PBR) offers many advanced features, including selection and forwarding of traffic to discreet Virtual Routing and Forwarding (VRF) instances, as well as Enhanced Tracking of the availability of next-hops. More about PBR you can read here.

Before we start this tutorial please download the topology file which contain the routers connection, BGP topology and some explanations. As you can see in the topology file, traffic going from R4 to R5 will choose the shortest path through R1-R2. For this tutorial let’s assume that we want the traffic from R4 to R5 (and viceversa) to flow through path R1-R3-R2 (BGP is full mesh configured among these devices). For this we need to apply Policy Based Routing (PBR) on R1 and R2. What is PBR basically doing? It will change the next-hop for interesting traffic to R3 on this devices.

Please see below the tutorial about how to configure PBR:

Cisco-routing cisco, PBR, policy based routing, traffic, traffic manipulation

Sometimes you have a connection between 2 routers that you want to test with something more than a ping. Cisco devices have a hidden command which is actually a very powerful testing tool for your TCP connection.

The command is “ttcp” and you will not find it in the the default list of commands of a Cisco device. So, even if you use help ( “?” mark at the router prompt) this command will not be showed to you.

For our testing we will use the same topology as in the previous posts. If you do not have it please download it here. Since this is a point-to-point TCP connection testing we will not use any fancy routing protocol or other networking protocols.

See the tutorial below:

Cisco-routing cisco, hidden commands, hidden tools, tcp, ttcp