We are trying to setup a phone system at an office using Hughes net. We may have to fall back to DSL but I was curious if this even works? I have 5 phones. All work,and internet is 45/1 but the voice is delayed. Not choppy but long delay
I am a Viasat dealer (formely Exede, wild blue)
You can never overcome the latency from sending a packet 26,000 miles up into space and then back to earth again. I hate to be the bearer of bad news but SAtellite Internet and Voip currently do NOT play well together. I tried unsuccessfully to make it work - it just won’t. Your ping times with satellite internet will exceed 700ms and to avoid delay you should be well under 100
That’s your Jitter Buffer compensating for the long ping times.
looks like we have to go back to DSL
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We spent hours a few years ago trying to make it work. We adjusted Jitter Buffer settings, in the phone, in the PBX, we did a little dance, sang a little song, never had success.
What’s funny is that Viasat sells their own residential voip phone product. Even there own voip ATA has a very noticeable and distracted delay. The actual satellite company could not even get their own product to work delay free.
In a typical hub and spoke sat network, data goes up to the satellite, back down to the earth station/data centre, out to the end user, with the process repeated for the return path. This “double hop” can be eliminated using a Mesh topology which allows terminals to intercommunicate directly, halving the ping time. Even there, the latency is still pretty noticeable, at around 400mS, even on a service with an adequate committed information rate.
It’ll never get any better…thankfully phone traffic via satellite is almost non existent now, the latency was terrible and the proliferation of fiber optic to cover long distances saved us all from having to use it day to day.
Just curious, would using g.729 codec help any?
g.729 is used routinely in these situations already as Satellite bandwidth is very expensive, especially the dedicated flavour, and it just adds to the general crappiness of voice over vsat. Satellite only comes into its own in areas where there are absolutely no alternative services available.
In very simple math, where the orbital height of a geostationary satellite is about 23000 mph and
the speed of light, is about 186000 mph then the two way trip is 23000/186000*2 = approx. 250 ms, that’s with the satellite directly overhead and you are on the equator.
It matters not how the data is compressed.
Given cumulative psychoachoustic research, you would best to train your users to use a simplex audio path ( you now, the one in Airplane! (1980) , Oveur, over)
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