In a satellite-based Internet system, satellites are used to interconnect heterogeneous network segments and to provide ubiquitous direct Internet access to homes and businesses. This article presents satellite-based Internet architectures and discusses multiple access control, routing, satellite transport, and integrating satellite networks into the global Internet.

A satellite ATM network has been envisioned as the next information super-skyway.There has been a migration from traditional bent pipe satellites to onboard processing) ATM satellites. The current congestion in the Internet has motivated the use of alternate pathsusing satellites to support global Internet transport and access. This article presents the various system and protocol layer architectures of SATM networks, he global information infrastructure (GII) of the United States has included satellite asynchronous transfer mode (SATM) as part of the communications infrastructure to support global mobile communications, information transport and access. The Telecommunications Industry Association (TIA) has recently formed an SATM group to study the various technical issues (e.g., reference models, media access, and mobility management) related to SATM. In addition, the ATM Forum Wireless ATM Group has established liaison with TIA to initiate standardization efforts on SATM [l]. This article reflects the increased interest expressed by industry, academia, and regulatory bodies in SATM network architectures.Current satellite network configurations comprise mainly ground, user, and space segments.The ground segment consists of gateway Earth stations (GESs), a network control center (NCC), and operation control centers (OCCs). Satellites communicate with fixed and mobile users via satellite-user links and gateway sta-tions. Location tracking of mobile terminals is performed at GESs. Most of the GESs a r e connected t o mobile switching centers of the land mobile network. The ground NCC provides functions such as mobile registration, verification, billing, network database distribution, and network resource allocation and management. OCCs, on the other hand, are responsible for satellite orbital tracking, ranging, and control. Processed information from OCCs is then distributed to GESs in order to support location tracking and handoffs. The user segment relates to a fixed, handheld, or ~ ~ ~~ ~~ ~