Hi,

I have just set up my two 5508s with software 7.5 both are in LAG mode cross stacked to two 3750X switches (in a stack obviously). Redundancy is working great, or it was, until I went into testing the HA scenarios...

• Turn off the Active 5508 while the pair are synchronized results in the standby becoming Active. Great.
  
• Disabling the Portchannel connecting to the Active unit results in the standby becoming Active. Great.
  
• Turning off one switch results in the Active remaining active as one half of the the port channel is still up. Great.
  
• Turning off both switches results in the Active staying the active and the standby staying standby, turn the switches back on and everything comes back just fine. Great.
  
• Turning my whole infrastructure off then only booting up the controllers results in the two controllers not being able to discover each other and subsequently results in 'Maintenance mode' which requires a reboot. Not good!
  

Can anyone explain why the controllers wont discover each other when the LAN is off? They have a direct connection from their redundancy ports.

Thanks in advance,

Laurence