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VoIP for Deployed Soldiers?
rickbassham asks: "With VoIP really catching on these days, I decided to look into it for keeping deployed soldiers in touch with family and friends. I am currently a soldier in Iraq, and have the ability to get satellite-based internet, thanks to a few of the locals. While individually it is prohibitively expensive, a group of soldiers can come together to purchase a decent-to-high-speed internet connection. One of my plans is to link other soldiers to Vonage or another VoIP provider, so they will be able to keep in touch. Understanding the latency issues with VoIP via satellite (not to mention the other disadvantages), what upload speed does Slashdot recommend as a minimum for a QoS enabled connection for about 15-20 soldiers? The same for a non-QoS connection? What recommendations do you have for a good VoIP provider?"
I used VoIP in Iraq/Kuwait when I was there.
Worked great. As long as you only go through 1 sat hop, it really wasn't that bad. It's better than nothing. I used packet8 out there btw.
Back in the US,
ChiefArcher
I work for a VoIP company that sells wholesale termination to customers in various coutries around the globe. Many of our customers come from locations where a landline isn't an option, and use satellite to carry their VoIP to us. From their experience we can say that on average, you're going to be able to handle about 7 simultaneous calls per 128Kbits of upstream. The calls themselves only take up about 12Kbits (each direction) per call, but there will be other data you're likely to be contending with that will eat up some of your available bandwidth.
As others have said, latency is going to be a problem, but from that part of the world, your likely already experience the joys of satellite latency in your "normal" calls. Again, our experience here is that as long as you can keep your latency below about 750ms you're going to have usable calls. A big factor here is the number of satellite hops your provider is send you through. A single hop will keep you under 750, while two hops will generally break the 1000ms barrier.
Anyway, hope those numbers help you in your considerations, and take care.
I saw this post and felt I should reply to address some misconceptions about voip and satellite. As CTO of an Iraqi ISP http://www.tigrisnet.net/ who offer wireless broadband service throughout Baghdad and Basra, I have many customers who are like you, groups of soldiers who got together to buy a connection for their barracks.
Our wirless broadband is fed by dedicated bandwidth over C-band satellite so the latency to our NOCs in downtown Baghdad and Basra is around 550ms but absolutely constant and reliable at that rtt, unlike VSAT services which are normally heavily contended and can indeed show wildly varying ping times in the 1000-2000ms range, indeed very bad for VOIP, either SIP or skype wont like that.
Of course round trip time is twice the delay that will affect voice calls, as voice delay is only the "throw" from my phone to your phone for a RTP packet. So around 1/4 sec of one-way delay makes for very acceptable voice quality.