Latency Of Satellite Internet Service
Satellite Internet service illustrates the difference between latency and bandwidth on computer networks. Satellite Internet connections possess both high bandwidth and high latency. When loading a Web page, for example, most satellite users can observe a noticeable delay from the time they enter a Web address to the time the page begins loading. This high latency is due primarily to propagation delay as the request message travels at the speed of light to the distant satellite station and back to the home network. Once the messages arrive on Earth, however, the page loads quickly like on other high-bandwidth Internet connections (DSL or cable).
Network tools like ping tests and traceroute measure latency by determining the time it takes a given network packet to travel from source to destination and back, the so-called round-trip time. Round-trip time is not the only way to specify latency, but it is the most common.
On DSL or cable Internet connections, latencies of less than 100 milliseconds (ms) are typical and less than 25 ms desired. Satellite Internet connections, on the other hand, average 500 ms or higher latency. Two key elements of network performance are bandwidth and latency. The average person is more familiar with the concept of bandwidth as that is the one advertised by manufacturers of network equipment.