VoIP

Can anybody be able to direct me into telling me what would be considered a good or a bad connection for VoIP services like VONAGE.
In using pingplotter what settings would be recommended for test my line for VoIP?

Thanks guys/gals

Out of curiosity are you having trouble with your line? I've been having issues with my Vonage this evening which I'm trying to troubleshoot

At this time no but when it does happen i would like to know what to look for.
What have you found out so far.

The following are "generalizations" about VoIP network quality needs. Without specifics, it's impossible to comment with a whole lot of authority, but here are some things to think about.

The most important thing for VoIP is to have solid latency with no packet loss.

"Solid latency" means a latency that doesn't change a whole bunch. Even a high latency can support a VoIP connection if it's consistent. The higher the latency, the more "lag" between the time you talk and the time the other side hears you, but this is only noticeable at the point where you stop talking and you expect them to answer back - a big "silence" there might indicate high latency (kind of like talking from the US to Australia via a satellite link - the latency on a standard phone line via satellite gives noticable lag).

Packet loss is a real killer for VoIP - each lost packet needs to either be retransmitted, or it will mean a small portion of the voice is lost. Either of these can cause delays and garbled voice.

Getting a lot of variance in latency is similar to packet loss, but instead of packets not arriving at all, packets might arrive out of order. At some point, the voice service will start to drop late-arriving packets because they arrive too late and are no longer relevant to the voice that is currently being played. A combination of early and late packets is a challenge. This is often called "jitter".

Now, high latency is something that should be minimized, but in the absense of packet loss and "jitter", the sound quality of the call will still be high, just slightly dealyed. Once you start to add jitter or packet loss, latency can make the call quality worse, however.

The ideal situation is to have a solid black line in the time graph of PingPlotter, similar to the image below. This would result in a relatively good voice connection. If you start to see significantly more spikes and more red, the connection quality will degrade.

You're *shooting* for packet loss < 2% (2% can still cause problems, but usually not), and latency variations of no more than about 50-100ms. An occasional variation bigger than this isn't an issue, but constant large variations will cause problems.

in the instance that one would like to troubleshoot ECHO problems, how would we go about it?

This is exactly what PingPlotter does - it uses ICMP echo requests / replies and measures latency and packet loss.

Run PingPlotter continuously. Look for periods of high latency volatility (jitter), packet loss, or areas where latency is higher than normal. Use the facilities in PingPlotter to locate the hop that is most likely to contribute to the problem. Depending on where this hop is, take action based on the results you find (that action might be to decrease your internet usage while making a call, or it might be to contact your ISP to have them research the problem).

For some examples of how to do this, see http://www.pingplotter.com/tutorial and look at the "Interpreting results" section.

I'm refering to ECHO that is heard on the phone.
If we get packet loss or jitter the packets are just dropped which causes cutoffs but ECHO is something else...

Please advise

Ahhh. Voice echo...

This is not an area of expertise for us, but a search around the internet shows that it could be latency related *a bit*, but that's only because latency makes it more apparent. More likely is that there is some kind of feedback between the speaker and microphone of the person you're talking to, causing the echo. With no latency, this doesn't really matter - as latency increases, though, it becomes more and more distracting.

It looks like there are network devices that cancel echo, but they don't do this by modifying the network characteristics as much as they do it by detecting the echo and removing it.

I did a Google (and Google groups) search on VoIP, Echo and network and came up with a lot of good material on this topic - especially in Google Groups.

PingPlotter doesn't show you echo at all - it's probably being caused by something that's a couple of "layers" away from the raw network.

- Pete

Thanks for your reply.