I have an Adtran 1638P that has a Voice and Data VLAN with a phone system in VLAN 200. I have a voice VLAN IP Interface on VLAN 200. I am trunked back to the customer's Cisco Small Biz switches. The problem I'm having is that my phones drop connection from the phone system sporadically. There does not appear to be a pattern to the drops. I suspect the issue is the Adtran 1638p because when I ping from a PC in the voice VLAN, I drop pings to the address of the phone system. I also drop pings from the CLI of the 1638P to the phone system. At the same time the pings are being dropped, I also have a laptop in the AUX port of the phone system as well, and that never drops pings. So, since I cannot ping from the CLI of the switch to the phone system, I think the 1638p is having an issue. Once the pings start responding, I can do a traceroute to the phone system IP and it just shows me the phone system IP, indicating that it indeed does not go anywhere else (gateway etc) except directly to the phone system as it should. Thoughts?
I will attempt a firmware upgrade as this is currently at 11.10.1.
Look for errors on the interfaces, specifically the one connected to the phone system. Perhaps a duplex mismatch?