H3C Technologies H3C SR8800 - Manual (Page 172)

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Figure 41 Diagram for multi-hop PW
As shown in Figure 41 , PE 1 and PE 2 are in different ASs. To set up a multi-hop PW between PE 1 and
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.
VPLS configuration task list
Complete the following tasks to configure VPLS:
Task Remarks
Configuring LDP VPLS
Enabling L2VPN and MPLS L2VPN Required
Configure either
type of VPLS as
needed
Configuring an LDP VPLS instance Required
Configuring BGP VPLS
Configuring the BGP extension Required
Enabling L2VPN and MPLS L2VPN Required
Configuring a BGP VPLS instance Required
Binding a VPLS instance Required
Configuring MAC address learning Optional
Configuring VPLS attributes Optional
CE 1
PE 1 PE 2
ASBR 1 ASBR 2
PW 1 PW 3
CE 2
PW 2
AS 100
AS 200
MPLS backbone MPLS backbone