switch based WDS failover to AP based WDS

[solomonthuo]

The document on cisco 6500 WLSM detailed design and implmentation guide details that it is not possible to have a switch-based WDS fail-over to AP based WDS. However it shows one can implement an SSID that is non-WDS and another SSID that is WDS enabled that works with the WDS configured in the WLSM module. IS this the only possible option and if it is, what are the administrative tasks involved incase the link between the APs and the WLSM fails in which case the clients have to use the non-WDS SSIDs. Since it is not possible to specify two WDSs when switch-based WDS is used can one configure an access point with WDS and then put it on standby such that when the link fails, an administrator gives the IP address of the WLSM to the WDS access point ?

[vmoopeung]

WLSM uses a redundancy mechanism very similar to HSRP. However, there are some differences that are described in this section.

As with HSRP, the active and standby WDS processes exchange keepalives (every 3 seconds by default) and the standby takes over after not hearing the hello messages for a period equal to the hold time (10 seconds by default).

You can configure a "priority" under the standby configuration to influence which WDS becomes active at boot time. Differently from an HSRP implementation on routers, the priority is only considered at boot time because the WDS implementation of HSRP does not consider preemption. After the standby becomes active, it stays active even if the other WDS comes back up and has a higher priority. This was done to minimize the traffic interruption because of the WDS failover.

http://www.cisco.com/en/US/netsol/ns340/ns394/ns431/ns434/networking_solutions_implementation_guide09186a008038906c.html#wp37400