MPLS Fundamentals

AToM Tunnel Selection

The AToM Tunnel Selection feature enables you to steer the AToM traffic through the MPLS network over a path that you specify. For this to work, you need to set up an MPLS TE tunnel from the PE to the PE router and then specify that the AToM traffic should take the TE tunnel instead of the default shortest labeled path. In addition, you can specify whether fallback to the default path is desirable when the TE tunnel fails.

Figure 10-21 shows an MPLS network with MPLS VPN and AToM customers. The CE routers CE1 and CE2 are part of one MPLS VPN network, whereas CE3 and CE4 are two CE routers that are connected through AToM. Normally, all labeled traffic follows the top path because it is the shortest path through the MPLS ...