As the title suggests, i am running an MP20 V4.92 with an OAS V2.05, running 10 channels of SIP.

The SIP sits on a 100/100 bearer with a Watchguard as the main firewall, previously it was a CISCO but this has been swapped out due to a number of reasons.

Phones use VLAN ID 20 and my switches are configured with VLANS for data and phones, the system LAN ports on the data switch are set to PVID.

The OAS seems to be getting knocked out every 30-60 mins, a reboot of the OAS will resolve temporarily. Checking in connection status i can see the ports status showing as NONE, rebooting returns them to IDLE.

This ONLY happens when the data network gets connected to our POE switches, we require a link from the data network as were running samsung xchange clients.

I have changed the OAS as initially i thought this was the fault.

I have a second gateway that can be used for back up purposes, if i change the gateway on the system to look at this connection and move the SIP over and disconnect the data Link, the OAS fault never appears.

Any ideas? im thinking its a data network issue for obvious reasons, but where do we start with fault finding this one!

Wireshark trace on the OAS card.

Something on the network is hitting that card.

You have a conflicting IP address issue with the OAS card and another device on the network. Use a high IP number for OAS card like 253 or 254 then that should solve it. To check, unplug the OAS card from the network and ping it's address.