PPPoE sessions are synchronized between the redundant BNG nodes. The subscriber synchronization is achieved through Multi-Chassis Synchronization (MCS) protocol in a similar way it is performed for IPoE.
multi-chassis
peer <IP@>create
sync
local-dhcp-server
SRRP
sub-mgmt [ipoe | pppoe]
:
:
no shutdown
exit
no shutdown
exit
Two keywords, ipoe and pppoe enable a more granular control over which type of subscribers the MCS should be enabled.
Subscriber synchronization is important for following reasons:
Forwarding of downstream traffic between the redundant BNG nodes through a redundant interface is an artifact of how natural routing steers traffic through the network.
Subscriber instantiation on the node which did not originally create subscriber session. This drastically reduces downtime during the SRRP switchover.
Monitors operational aspects of the subscriber management through show commands.