Radius Load Balancing

We use Radius authentication for our corporate wireless users. I'm looking at load balancing our radius servers for our wireless controllers. We had an issue recently where one of the radius servers went down, all clients connected on that wireless controller to that radius server, lost their authentication. Hence, about 400 people dropped off the network. The server was physically up, but the service was hung. The controllers have both IP addresses of the Radius servers in their configuration. But have no way of knowing if the service is up or not. Only if the server was completely down.

 

 

My idea is to use the BigiP, use one VIP the controllers point to, and do the health checks. That way the controllers can send to one IP, and the BigIP manages the traffic.

 

 

Does anyone have experience with load balancing radius. I have already created a VIP, a UDP profile specifying the Datagram LB option. I also created a health monitor which checks radius the port. I would really like to build a good health monitor to actually check authentication and make sure the radius server is online. Any input is appreciated...

 

 

Thanks....