Hi guys, I have a 908e TA and Eth 0/1 is bouncing. We cannot ping the interface on and off though the TA remains up and continues to process calls incoming on Eth 0/2. Problem is that we have several sites pointing to Eth 0/1 for site to site Ext calls so whenever it goes down we are unable to dial extensions to that site. I already upgraded firmware to latest extended maintenance release. It had been working fine until an incident forced us to plug the 908e onto a different switch. The switch is brand new and has been configured exactly as the previous switch. Appreciate the help.
What does the output of "show interface" look like? Capture it and then do so again a few minutes later to see increases in error counts. Make sure both sides are either set to auto-negotiate speed and duplex (preferred) or both are hard-coded to match each other. Incrementing CRC errors, runts, and late collisions are a very good sign of duplex mismatch.
If this checks out, suspect the cabling. I've seen some 8-pin modular plugs that just don't seem to play nice with certain jacks. If that checks out 100%, look into possible spanning-tree issues.
Another possibility is LLDP causing the switch to try to negotiate to a different speed or duplex. Adtran gear has been buggy with LLDP showing impossible speed/duplex combinations with Polycom phones forever. This is usually just a cosmetic annoyance but some switches may misbehave and actually try to negotiate to it. Turning off LLDP completely on the TA908e may be a good idea if you don't need it.
If the interfaces on both the TA908e and the switch look clean, look for spanning-tree issues on the switch. Perhaps not on your link but also check other ports on the same switch.
When I do show interface Eth 0/1 shows no error. What could this mean? Wouldn't a problem with the physical link show errors on the interface?
No errors, no runts, no collisions, no resets? Same on the switch? Does it show configured for and negotiated full duplex?
If both the router interface and the connected switch show no errors, I'd look for something else on the switch like spanning-tree.