Requesting an explanation for information

Posts: 1 · New Forum Member Joined: Jun 01, 2007 Posts: 1

I not used to using Voip but it has been great I am currently using Vonage but the voice quality sort of stinks. i get static and dropped calls at least once a week. I found a test from one of the other topics on this forum so I ran it this was my results. The thing is I don't under stand it can someone explain it to me.

Posts: 414 · Posted: Fri Jun 01, 2007 12:21 pm Post subject:

Well, the good thing there is that everything looks right on target on your test. Your MOS score is your connections ability to handle a Voip connection, and a score of 4.4 is very respectable. Both your upstream and downstream channels look very good. You have nothing to worry about with the results of that test.

As for your dropped calls, this could be anything from your internet connection dropping out or having a high period of packet loss all the way to your Vonage adapter overheating and intermittently locking up. We would need some more info to begin diagnosing this. A good start would be to follow the posting guideline in the stickied thread at the top of this forum entitled: What to post when having technical trouble with Vonage....

Posts: 10 · Vonage Forum Associate Joined: May 17, 2005 Posts: 10

MOS = Mean Opinion Score where 4.4 is high quality POTs line.
The test is being run with a real voice call and the remote tester is looking at the information in the voice RTP packets and confirming that (i) you are running with a high quality low delay codec (G.711 at 20 msec).

The key numbers are jitter and packet loss, in your trace jitter peaks at 28 msec (i.e sometimes the next voice packet arrives in 48msec time instead of the desired 20msec time) but your jitter buffer should be big enough to absorb this (you can ask the Vonage rep to tell you your current jitter buffer setting, it should be at least 40 msec)

Packet loss is zero so there is no drop in voice quality (due to the internet connection) also with G.711 packet drop will sound like clicks.
or pops

Your Signaling quality is just for the messages to establish and tear down the call.

Your static is probably due to the analog noise on the "talk battery" voltage line inside your router affecting the SLIC device that is providing the interface to your telephone set (faulty router or bad SLIC config for your actual telephone line)

If you hear static BETWEEN each dialled digit when making a telephone call then your router has a hardware fault (see above)

I had the same problems and ditched my router for a new one and instantly the static went away. When I called to cancel my entire Vonage phone service they INSTANSTLY offered to send me a new router overnight so I am sure Vonage is quite aware of this router hardware issue (in my case too late since I had switched to another Voip provider)

I am quite aware of what a noisy "talk battery" voltage inside the router internals sounds like (I am only saying this in passing on my hardware design experience as a SIP voice router designer)