17.1 Overview of satellite models

Exact simulation of satellite networks requires a detailed modelling of radio frequency characteristics (interference, fading), protocol interactions (e.g., interactions of residual burst errors on the link with error checking codes), and second-order orbital effects (precession, gravitational anomalies, etc.). However, in order to study fundamental characteristics of satellite networks from a networking perspective, certain features may be abstracted out. For example, the performance of TCP over satellite links is impacted little by using an approximate rather than detailed channel model- performance can be characterized to first order by the overall packet loss probability. This is the approach taken in this simulation model- to create a framework for studying transport, routing, and MAC protocols in a satellite environment consisting of geostationary satellites or constellations of polar-orbiting low-earth-orbit (LEO) satellites. Of course, users may extend these models to provide more detail at a given layer.