We have Avaya IP phones in our setup and they are connected to Linksys POE switches and are working fine. We have now got 5 Cisco POE as a replacement for the linksys switches.
Phone Vlan is 12
Initially none of the IP phone would acquire the IP address from the DHCP server. After tshooting the issue for sometime, one of the fone got the IP address and it started working fine. now if the same phone is connected to anyone of the 24 ports of the switch, it acquires the IP and works fine but others are still not getting the IP address from the server .. All the switchports have identical settings
After more tshooting i checked the dynamic mac address-table of the POE switch and found a very weird thing
1) If the fone (which is working fine) is connected to any of the 24 ports, the mac address shows that its registered in the vlan 12
2) if a different fone is connected to the same port then its mac address gets registered to vlan 1.
Before this i would use switchport voice vlan 12 and the phone which was working fine would get registered on all the ports. I order to make the others work i used switchport access vlan 12. After plugging the fone(different fone), it would register its mac address on vlan 12 but it would still not acquire the IP address.
This issue is very baffling to say the least.
Switchport configuration combination tried so far
switchport vlan 12
switchport access vlan 12
no cdp enable / with cdp enabled
with portfast and without portfast
with bpduguard enable and without bpduguard enable
changing the inline power and also making it auto
once again, the fone which works, works on all the ports without any issues, there is no static ip address defined on that.