Step 4: Set Up BGP on Routers in Your Network
Purpose
Before BGP can function in your MPLS network, you must define the autonomous system (AS) number on the routers in your network, and configure at least one group that includes at least one peer.
Optionally, you can configure a routing policy. The routing policy allows you to control the information shared with BGP neighbors and provides the opportunity to filter and modify the information you receive.
The BGP configuration in the MPLS network in Figure 4 consists of the following:
- A full-mesh IBGP topology, using AS 65432.
- All IBGP sessions peer between loopback addresses because significant stability advantages are gained.
- All routers are configured with one group,
group internal. - A
send-staticspolicy on routers R1 and R6 allows a new route to be advertised into the network.
The example network uses IS-IS Level 2 and a policy to create routes that are reachable through the LSP. However, IS-IS Level 1 or an OSPF area can be used and the policy omitted if the network has existing BGP traffic.
You can set up BGP throughout the rest of the network by repeating Step 1, Define the Local Autonomous System through Step 3, Configure a Simple Routing Policy as appropriate on other routers until all routers are set up with BGP.
Steps to Take
To set up BGP on routers in your network, follow these steps: