Multi-Hop Pw - HP 12500 Series Configuration Manual

When Spoke-PE 2 receives the packet from the PW, it determines by the MPLS label the VSI that the
5.
packet is for, and then forwards the packet to Spoke-CE 2.
NOTE:
In a hub-spoke network, you can configure only one hub-CE node.

Multi-hop PW

A PW cannot be setup directly between two PEs when:
• The two PEs are in different Autonomous Systems (ASs), where they cannot establish a singling
connection.
The two PEs use different PW signaling protocols.
•
In such cases, you can establish multiple continuous PW segments that function as a single PW, called a
"multi-hop PW", a virtual connection between the two PEs.
Figure 34 Diagram for multi-hop PW
As shown in
PE 2, you need to:
• Establish three PWs: PW 1 between PE 1 and ASBR 1, PW 2 between ASBR 1 and ASBR 2, and
PW 3 between ASBR 2 between PE 2.
Associate PW 1 and PW 2 on ASBR 1. Then, when receiving a packet from PW 1 (or PW 2), ASBR
•
1 removes the existing inner and outer labels of the packet and adds the inner and outer labels of
PW 2 (or PW 1) to the packet.
Associate PW 2 and PW 3 on ASBR 2. Then, upon receiving a packet from PW 2 (or PW 3), ASBR
•
2 removes the existing inner and outer labels of the packet and then adds the inner and outer labels
of PW 3 (or PW 2) to the packet.
Thus, PW 1, PW 2, and PW 3 are put end to end and a multi-hop PW is formed across the ASs.
NOTE:
Only LDP VPLS connections can form a multi-hop PW.
Figure 34, PE 1 and PE 2 are in different ASs. To set up a multi-hop PW between PE 1 and
131