+-----+
                    +----------+ PCE +--------+
                    |          +-----+        |
                    |                         |
                    | BGP Session 1(lo11/lo21)|
                    +-------------------------+
                    |                         |
                    | BGP Session 2(lo12/lo22)|
                    +-------------------------+
PF12                |                         |                 PF22
PF11                |                         |                 PF21
+---+         +-----+-----+             +-----+-----+           +---+
|SW1+---------+(lo11/lo12)+-------------+(lo21/lo22)+-----------+SW2|
+---+         |    R1     +-------------+    R2     |           +---+
              +-----------+             +-----------+