The MSAN is homed to UPE 1 and UPE 2 and has two ports, one in Inactive state and the other in Active state. The port in Inactive state does not forward data. As a result, heartbeat packets from either UPE fail to pass through the MSAN. How do I configure an mVRRP backup group to control the master/backup state of the UPEs' upstream VPLS session in this scenario?
Only the statuses of link and peer BFD sessions can determine whether an mVRRP backup group is in the master or backup state, because heartbeat packets from either UPE fail to pass through the MSAN.
Configure link BFD between UPE 1 and the MSAN and between UPE 2 and the MSAN. In addition, enable the link BFD session on the MSAN's active port to be up and that on the MSAN's inactive port to be always down.Configure peer BFD on the loopback interfaces of UPE 1 and UPE 2 to check for UPE-level faults, because peer BFD packets from UPE 1 and UPE 2 fail to pass through the MSAN.