.............................
                  .                           .
              +---------+                     .
 +------+     | Ingress |                     .
 |Source|  +->| RBridge |                     .   +----------+
 +---+--+  |  |   RB1   |                     .   |Forwarding|
     |     |  +------+--+  +----------+       .   | Element  |
     v     |      .  |     | Transit  |       .   |    Y     |
   +-------+--+   .  +---->| RBridges |       .   +--------+-+
   |Forwarding|   .        |   RBn    |       .      ^     |
   | Element  |   .        +-------+--+  +---------+ |     v
   |    X     |   .                |     | Egress  | |  +-----------+
   +----------+   .                +---->| RBridge +-+  |Destination|
                  .                      |   RB9   |    +-----------+
                  .  TRILL               +---------+
                  .  campus                   .
                  .............................