The Next-generation LEO System (NeLS) research center is conducting research and development of the global multimedia mobile satellite communications services using low earth orbit (LEO) satellites. Although the NeLS has less transmission delay and loss than a geostationary orbit (GEC) satellite networks (GSN), it has more line hits and transmission delay variations due to frequent handovers (HOs) and inter-satellite link (ISL) switchovers. Handover and ISL switchover depend on the routing algorithm (RA) and protocol. The authors developed new RAs to decrease the numbers of HOs and ISL switchovers. And the equipment to transmit moving images by MPEG-2 over IP with several functions peculiar to NeLS is also developed for establishing key technologies of multicasting services. This paper describes the developed RAs, the equipment of MPEG-2 over IP and the results of simulation.