Route Origin for VPNs

You can use route origin to prevent routes learned from one customer edge (CE) router marked with origin community from being advertised back to it from another CE router in the same autonomous system (AS).

In the example, the route origin is used to prevent routes learned from CE Router A that are marked with origin community from being advertised back to CE Router E by AS 200.

The following sections describe how to configure the route origin for a group of VPNs based on the topology illustrated in Figure 4:

• Configuring the Site of Origin Community on CE Router A
• Configuring the Community on CE Router A
• Applying the Policy Statement on CE Router A
• Configuring the Policy on PE Router D
• Configuring the Community on PE Router D
• Applying the Policy on PE Router D

Figure 4: Network Topology of Site of Origin Example

In this topology, CE Router A and CE Router E are in the same AS (AS200). They use external BGP (EBGP) to exchange routes with their respective provider edge (PE) routers, PE Router B and PE Router D. The two CE Routers have a back connection.