We are having sporadic weird issues with Polycom 501's at 3 new installations. We have dot1x deployed, with a auth, guest and voice vlans deployed on the switch ports(3750's) It appears that there is a issue with the port going to a unauthorized state (guest vlan) before the CDP packet from the Polycom can ask for and recieve the voice vlan. This causes the phone to try to get a DHCP address in the guest vlan range and hence it cannot get the correct voice vlan ip address so the TFTP config download fails. Also it appears that sometimes when we can get the phone to come up, they will be making calls successfully then they cannot make or recive calls. Turning off dot1x fixes this. Not sure what is going on here so as there is not too much debugging I can do. I am thinking about either turning up the dot1x EAp timeouts or decreasing the CDP interval. Fortunately the next deployments will be Cisco phones, but we are stuck with 120 Polycoms right now. One thing to note here is that most of the phones are 301's which work fine its just the 30 or so 501's and 601's
