******
                ..........*MDSC*..............................
             .            ****** ..                   MPI    .
          .                .        .                        .
       .                   .          .   PCInitiate LSPx    .
     .                    .             .   with VNAG        .
    .                    .                .                  .
   .                    .                  .                 .
  .                    .                    .                .
  v                    v                    v                .
******               ******               ******             .
*PNC1*               *PNC2*               *PNC4*             .
******               ******               ******             .
+---------------+    +---------------+    +---------------+  .
|               |----|               |----|              C|  .
|               |    |               |    |               |  .
|DOMAIN 1       |----|DOMAIN 2       |----|DOMAIN 4       |  .
+---------------+    +---------------+    +---------------+  .
                                         /                   .
                    ******              /                    .
                    *PNC3*<............/......................
                    ******            /
                    +---------------+/
                    |               |
                    |               |
                    |DOMAIN 3       |
                    +---------------+

MDSC -> parent PCE
PNC  -> child  PCE
MPI  -> PCEP