The WLAN-GW supports N:M warm standby redundancy on an IOM level. One WLAN-GW group can be configured with a set of WLAN-GW IOMs, and a limit of active IOMs. Each WLAN-GW IOM can only contain ISA hardware with the ISA BB image loaded. Any combination with other hardware or ISAs with another image is not supported and MDA-based redundancy must be used instead.
In IOM resiliency mode, all ISAs on an IOM are either active or standby and the maximum number of active resources is also configured at the IOM level using the active-iom-limit command. IOMs beyond the active limit act as warm standby and take over the tunnel termination and session management functions from a failed IOM. It is not possible to change the active-iom-limit while a system is running.