One of my SL2100 customers has a home user with an IP phone. The office where the 2100 is has Mediacom for analog line service. Last week he said call quality was so bad he couldn't use the IP phone. When I called him today he said it has gotten better and was ok. It sounded good to me. I've explained before that it depends on his internet connection. His reply is that when it happens his computer had no problems with internet activity, file transfers, etc.. Both ends have decent ISP connections.

The problem now seems to be that internal calls to or from this IP phone aren't always connected when called. In other words, intercom call to the IP phone - IP phone hears ringing, picks up, nothing there. Problem can also be from IP phone to the office too.

I suggested a VPN router for the IP phone. He took that to his IT folks, who said that device is usually provided, or specified, by the phone system mfg or vendor. I thought it would come from the network side, since it will communicate to the Sonicwall firewall in the main office.

I think the call quality and connection problems might be related. Is there a recommendation for which VPN device to use for this?

Thanks.
Jim

VPN won't help call quality and in fact will probably hurt it (if VPN fixes it it's a firewall/router issue). File transfers and internet connectivity mean nothing. You don't have dedicated bandwidth its a crap shoot. All you can do is make sure you equipment is set right and that SIP ALG is off. Wireshark is your friend. Check your port forwarding. If you are getting signaling port and not getting voice that UDP traffic needs to be checked. Some firewalls do not like that UDP flooding on IP phones. Make sure the remote site is not router with a router behind it. Seen this where the cable modem isn't in gateway mode.