1:1 redundancy provided with this feature only handles complete failure of WLAN-GW (either because of a chassis reboot or because of the number of operational WLAN-GW IOMs in WLAN-GW group falling below the number of active WLAN-GW IOMs, which operationally brings down the WLAN-GW group, and trigger switchover). For any partial failures (port, MDA or IOM failure), it is assumed there is network level redundancy, such that the soft-GRE tunnel is re-routed to the primary WLAN-GW. This ensures there is only one active WLAN-GW owning the subnets defined on the two WLAN-GWs (that is, allows local/local subnets). The DHCP servers state is synchronized between the two WLAN-GWs using MCS.
Supported access includes:
DHCPv4 relay to external server
DHCPv4 relay to local server
Pool name could be returned by AAA (framed-pool) in access-accept
Pool name could come from LUDB (as relay we would set use-pool-from-client). LUDB could be specified under group-interface or under DHCP server. LUDB or AAA returned pool allows support for per SSID pool selection. SSID is contained in circuit-id.
Local pool selection based on giaddr
DHCPv4 proxy (IP@ from AAA or IP@ from PGW/GGSN)
The unnumbered case works in relay and proxy scenarios. IPv6 is not supported (data-triggered auth and subscriber creation for IPv6 is not supported). Therefore, DHCPv6 server synchronization is not applicable. Also, IPv4 address from LUDB is not supported (as data-triggered authentication against LUDB is not supported).