CE1-A, CE2-A, and CE3-A are CE devices.  CE1-A is the hub CE for the Customer A network and is connected to PE1-AS1, which is the hub PE router for the Customer A network.  CE2-A and CE3-A are spoke sites and are connected to PE2-AS1 and PE3-AS1.  As shown in Figure 6-22, the PE-CE link between PE1-AS1 and CE1-A has two links.  One link is configured to forward routing information for VRF from_spoke and another link for VRF from_hub.  VRF from_spoke on PE1-AS1 is configured to receive routes from spoke sites CE2-A and CE3-A. VRF from_hub receives routes from CE1-A and sends that out to remote sites.  The sequence of steps that takes place in the hub and spoke environment is shown in Figure 6-22. 

Verifying MPLS VPN Hub and Spoke Routing for Sites Using Unique AS Numbers

The steps to verify MPLS VPN hub and spoke routing are

Step 1. 

Verify routing on hub PE and spoke PE – Example 6-46 shows that VRF from_spoke on PE1-AS1 has received routes from spoke site Routers CE2-A and CE3-A via the MP-BGP session.  VRF from_hub shows the routes received from CE1-A (hub CE).  Similarly, PE2-AS1 and PE3-AS1 also show that routes are received by each of the VRFs configured on them.