I have been trying to diagnosis a VOIP problem in one direction. This voice goes over satellite so the average latency is over 650ms. I have attached a short plot from the remote to my SIP termination. I was wondering if HOP 3 could be a problem, since it always shows very high jitter. The round trip jitter looks ok. When running PP the other direction none of the hops have this high of jitter. The voice sound fine to the remote but very broken from the remote. Any help would be appreciated.

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Hello.

You always have to look at the final destination first - if it's not showing Jitter, then any Jitter in intermediate hops is a reporting artifact of the intermediate hop only, which almost certainly doesn't affect the end result of your VoIP conversation. Hop 3 is almost certainly *not* your problem.

See here for details:

http://www.nessoft.com/kb/24

and here:

http://www.nessoft.com/kb/47

VoIP really requires latency of < 300ms to work reasonably well. 600 ms of latency is going to be a very challenging environment to make work well for voice. Probably not impossible, if you accept certain limitations, but pretty bad (as the MOS score shows).

- Pete