We're seeing a reoccurring problem with the 4011 units we've deployed in the field. After some time the lock up, respond to ping but are UN-reachable. They route traffic bu the DHCP server stops working. We've seen this with every unit we've deployed and firmware updates aren't resolving the problem. this is especially perplexing as the setting we use are the same for 2011, 3011 and hex PoE units and the problem only seems to exist in 4011 units. we've tried powering with DC and POE and the problem continues. Its unrelated to temperature or operating time AFAIK.
We are running ospf, and virtual bridge interfaces if that makes a difference.
Has anyone else seen similar behavior?