Subscriber Services: DHCP session liveness detection based on ARP and neighbor discovery packets

You can configure bidirectional Layer 2 liveness detection for directly connected DHCPv4 and DHCPv6 subscribers using ARP packets for v4 and neighbor discovery (ND) packets for v6. You can configure Layer 2 liveness detection for both DHCP local server and DHCP relay clients. This method of liveness detection enables the host and the broadband network gateway (BNG) separately to determine the validity and state of the DHCP client session and to clean up inactive sessions. The liveness detection send functionality enables the BNG to determine client session state based on the host response to request packets the BNG sends at a configurable interval. The liveness detection receive functionality enables the client host to determine session state based on the BNG response to ARP or ND packets sent by the client to the BNG. Layer 2 liveness detection (AR/ND) and Bidirectional Forwarding Detection (BFD) are mutually exclusive.