M:N subscriber redundancy on BNGs

You can configure broadband network gateways (BNGs) to provide interface-level redundancy for DHCP subscribers that are on the same static VLAN and use the same access interface. Failover from primary to backup BNG is transparent to the clients because the subscriber sessions remain up. You must configure DHCP active leasequery with topology discovery on peer DHCP relay agents on the primary and backup BNGs to support the redundancy.