To configure a distributed service from ALA-A to ALA-B, the SDP ID (1) must be specified in the service creation process to bind the service to the tunnel (the SDP). Otherwise, service traffic is not directed to a far-end point and the far-end devices cannot participate in the service (there is no service). To configure a distributed service from ALA-B to ALA-A, the SDP ID (5) must be specified.
The following figure shows MPLS service distribution point pointing from ALA-A to ALA-B.
Figure: MPLS SDP pointing from ALA-A to ALA-B
