One-Way VS. Two-Way

In One-Way satellite services use satellite networks to broadcast information to your computer but leverage alternative solutions for the return connectivity path (dial, wireless, etc). Two-way satellite services, in addition to broadcasting to your computer, also transmit from the customer location back to the network over the satellite.

The original intent for satellite networks was broadcasting, from one central location to many remote sites. Satellites were not originally designed for Two-way (bi­directional) transmission of information. Two-way satellite Internet services challenge satellite networks to do something more complex than most were designed for. Subsequently, there are a number of “side effects” of using current satellite networks for Two-way communications:

Satellites used for broadcasting Internet traffic are located in constant (geostationary) orbit approximately 23,000 miles over the equator. When using a Two-way satellite system for surfing the Internet, information must pass through this satellite twice (once for the request, once for the download), traveling a total of approximately 92,000 miles. This lengthy trip results in delays ,referred to as latency, before new web pages are displayed. This delay is generally from to 700 to 1300 milliseconds for Two-way satellite communications (as reported by Hughes and StarBand).

One of the issues of these delays that affect the web surfing experience is that after 700 milliseconds, standard web protocol considers information packets (i.e. page requests) lost, many times resulting in a “timeout”. The request is then automatically resubmitted by your computer, sometimes several times before the information packet is actually delivered. While this process is invisible to you, you’ll experience it as waiting time, not unlike the waiting that you experience with a traditional dial-up service. Latency can also affect the performance of certain customer applications, such as VPN and networking, causing them to not function over the two-way system.

The waiting-time for One-way satellite (satellite plus a telephone line) is approximately 400 milliseconds, well below the 700 milliseconds required by web protocol. Because information packets arrive before the ‘timeout’ web pages are delivered to you immediately resulting in a FASTER surfing experience overall with the One-Way satellite service.

Reliability

Delay Issues