Using spanning tree in VPLS

[r-karamad]

Hi guys. I have some questions about spanning-tree in VPLS. This is my topology:

BNG is directly connected to PEs. The physical link between BNG and every PE must be an active link for subscribers VLANs. I wanna use pseudowire in a bridge domain as a backup link on every PE. If the direct link is forwarding, it pass the subscriber's traffic to BNG, but in the case of link failure, the pseudowire has to pass the subscriber's traffic on the other path.

I think this idea can be implemented with MST. Normally, "PW A" on NPE2 and "PW B" on NPE3 have to be in blocking state. With failing the physical links to BNG, the PWs change theirs states to forwarding. 

I'm reading some articles about spanning tree in VPLS on ASR 9000 platforms but i'm confusing how it's configured in a bridge-domain.

First my question is that this idea is correct? If yes, please help me about the configuration and verifications?

Thank you!

[r-karamad]

Hi, i found this topic. 

L2VPN Pseudowire Redundancy with Layer 2 Local Switching

connect vlan-vlan Ethernet1/0.2 Ethernet2/0.2
  backup peer 10.55.55.3 1101 pw-class mpls

IOS-XR does support this technique? How's the configuration in IOS-XR, on ASR 9000 platforms?

[Eddie Chami]

The backup of a local interface xcross connect in XR is another physical interface:

RP/0/RSP0/CPU0:ASR9K-PE1-R0(config-l2vpn-xc-p2p)#show configuration 

Mon Sep 21 19:27:54.227 UTC

Building configuration...

!! IOS XR Configuration 5.3.1

l2vpn

 xconnect group test1

  p2p test2

   interface Bundle-Ether1.10

   interface GigabitEthernet0/1/0/3.2

  !

 !

!

end

RP/0/RSP0/CPU0:ASR9K-PE1-R0(config-l2vpn-xc-p2p)#backup ?

  interface  Specify the attachment circuit

RP/0/RSP0/CPU0:ASR9K-PE1-R0(config-l2vpn-xc-p2p)#

[Eddie Chami]

How about running MCLAG between the BNG and NPE's, it would reduce your complexity, you'll still have decent redundancy and reduce the number of PW's.

Eddie.

[r-karamad]

thanks for the answer. MCLAG is a solution but with MCLAG, we have active/standby redundancy, one of the POAs will be standby. How can i use MCLAG so that DSLAM's traffic behind the NPE3 is flooded on BE10 (direct link) to BNG, or on top of the figure, DSLAM's traffic behind the NPE2 is flooded on BE5 (direct link) to BNG.