Both the WLCs in HA setup keep track of gateway reachability. The Active WLC sends an Internet Control Message Protocol (ICMP) ping to the gateway using the Management IP address as the source, and the Standby WLC sends an ICMP ping to the gateway using the Redundancy Management IP address. Both the WLCs send an ICMP ping to the gateway at a one-second interval.
Standby by default will be exchanging keepalives with primary and also parallely checking gateway reachability. Gateway reachablility check if for network related issues and keepalives for box failure issues.
The above algorithm will slightly change in event of failure. That is, it introduces additional ICMP to active WLC (not gateway) if keepalive is unanswered.
This is new ICMP to active WLC and gateway reachability check from standby will run parallel asusual.
Lets run through the algorithm for box failure from doc :
In the case of a Network Failover (that is, the Active WLC cannot reach its gateway for some reason), it may take 3-4 seconds for a complete switchover depending on the number of APs in the network.
You can find stats using command :
show redundancy statistics Redundancy Manager Statistics Keep Alive Request Send Counter : 16 Keep Alive Response Receive Counter : 16 Keep Alive Request Receive Counter : 500322 Keep Alive Response Send Counter : 500322 Ping Request to Default GW Counter : 63360 Ping Response from Default GW Counter : 63360 Ping Request to Peer Counter : 12 Ping Response from Peer Counter : 3 Keep Alive Loss Counter : 0 Default GW Loss Counter : 0 Local Physical Ports 1...8 : 10000000 Peer Physical Ports 1...8 : 10000000
Let me know if this answered your question.
Thanks for taking time to answer our queries.
It is all clear to to me now.
Keep up the good work.
We are looking at deploying two 5508 in HA (Active/Active), is there a document or design blue print that would help us with the basic deployment and configuration of the units. Those two units would be homed in on two HA 6509E switches interconnected to each other using etherchannel trunks and running HSRP between them.
We are also looking at deploying two 5760 units in the exact same scenario as above. Your feedback would be much appreciated.