I have a customer with a UC540 and about five phones in his office. He also has two remote phones at his home. He prefers to work from his home.
The office has Time Warner internet, and so does his home.
A tracert from his home to his office is only approx. eight hops.
The UC540 is setup with a Broadvox SIP trunk. All calls come/go through that, there are no POTS lines.
The system works flawlessly about 97% of the time. It has worked great for the last month. Today, it doesn't work well. At his remote phone, he is getting chopping inbound audio. It doesn't matter if he is on a SIP trunk call, or an intercom call to the office, his inbound is choppy.
I have brought one of his remote phones to my office (where I also have TIme Warner) and have the same problem.
So this seems to be a connectivity problem at his office. It would seem that we're dropping outbound packets.
The people in the office can make/take calls over the SIP trunk no problem. So it seems to me that the VPN is more sensitive to dropped packets than using a phone directly connected to the UC540 that is using the SIP trunk. Because there is no VPN employed for the SIP trunk, it seems less sensitive to dropped packets.
This happened a month ago and I was able to show Time Warner that the office connection was dropping packets when I did a ping -t from my office to his. Packet loss was on the order of 3%. So Time Warner replaced the modem and a cable inside his office building and the problem clearned-up. This time around, though, it doesn't appear that ping helps, all pings are responded to.
So I guess my question is, how do I troubleshoot connectivity issues in such a way that I can show Time Warner that there is a problem that needs fixing.
