Multimedia satellite networks and TCP/IP traffic transport

To meet an increasing demand for multimedia services and electronic connectivity across the world, satellite networks will play an indispensable role in the deployment of global networks. A number of satellite communication systems have been proposed using geosynchronous (GEO) satellites, medium earth orbit (MEO) and low earth orbit (LEO) constellations operating in the Ka-band and above. At these frequencies, satellite networks are able to provide broadband services requiring wider bandwidth than the current services at C or Ku-band. Most of the next-generation broadband satellite systems will use ATM or "ATM-like" switching with onboard processing to provide full two-way services to and from earth stations. The new services gaining momentum include mobile services, private intranets, and high-data-rate internet access carried over integrated satellite-fiber networks. Several performance issues need to be addressed before a transport layer protocol like TCP can satisfactorily work over satellite ATM for large delay-bandwidth networks. The authors review the proposed satellite systems and discuss challenges such as traffic management and QoS requirements for broadband satellite ATM networks. The performance results of TCP enhancements for Unspecified Bit Rate over ATM (ATM-UBR+) for large bandwidth-delay environments with various end system policies and drop policies for several buffer sizes are presented.