This question came in on one of the forums on the Realtime VoIP Community. I'm going to share it and my reponse here as well as there to get the most exposure.

Help! I am trying to do satellite Internet, but have whave I have been told is the ping rate for most satellite companies is 400-600 ms. Also my VoIP service (www.myphone.com) says they have customers who use satellite Internet. But they also say the ping rate needs to be 200 ms or less for best VoIP performance. I am waiting for an answer from them on what satellite company works. Does anyone have success with a satellite Internet company? I will wait for a reply.

This is both an easy question and a difficult one because your mileage may vary based on factors no provider can guarantee.

The ping rate referred to is the delay in delivering packets across the connection. If you're getting a 400-600 millisecond response, your satellite provider may only be giving you half the story. Geostationary satellites orbit at around 23,00 miles altitude. Typical ping responses on satellite connections, in my experience, range in the 1200-1500 ms time. They may be giving you one-way delay.

When you use a satellite connection, your signal (packets) have to be sent 23,000 miles to the satellite, where they bounce 23,000 miles back down to an earth station. This takes time, and I've never seen a civilian satellite with a much better response rate.

VoIP truly does require 150-200 ms delays for optimal performance. 500 ms may be tolerable, but when you get up inte 1500 ms range, VoIP service is degraded. That doesn't mean it's unusable. What it means is that when you speak, your voice transmission is delayed over a tenth of a second in getting to the person you're speaking with. This is quite detectable to the human ear, and can be very distracting during a telephone conversation.

I used satellite Internet for three years when I lived in the country in Vermont. My experience was mixed. VoIP works. Skype works. SIP-based VoIP works. But they both suffer serious quality issues. The delays induced by the limitations of satellite delay degraded most conversations to "walk talkie-like quailty." What I mean by this is best explained by how I'd often open a call when the called party answered - "Hi this is Ken. I'm on a satellite connection, so we make experience some delays. Over."

The satellite delays are significant enough to make VoIP pretty unusable for general business purposes. It might be acceptable for personal conversations with family members, but most people I know found the call quality just unacceptable. This is not a bandwidth issue. It's a limitation of how long it takes to transmit the signal to a satellite and back to earth. The technology delivers the data, but the delay is not generally suitable for VoIP traffic.

You may get it to work, and you may find it usable at times, but in general, it's not something I know anyone finding useful on a regular basis, especially for business caliber quality. And while various satellite providers may tell you it will work fine on their network, unless you talk to multiple users who all express good results and use it regularly, I wouldn't be inclined to believe you'll find very good performance results from any consumer-grade satellite provider at this point.

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