PLR: Point of Local Repair. It is the head node
of the protection LSP, that is, the location where the fault occurs. When
protection occurs, the protection label is pressed at this point, and the
normal label is encapsulated in it.
MP: Merge Point. It is the tail node of the
protection LSP. When the protection occurs, the protection label is displayed
at this point, and the protection label is forwarded normally according to the
original label.
1. Packet forwarding before
TE FRR switching

2.Packet forwarding
after TE FRR switching