Network Architecture and SONET Services in the NASA-ARPA Gigabit Satellite Network using NASA's Advanced Communications Technology Satellite (ACTS)

The Gigabit Satellite Network, a project jointly sponsored by ARPA and NASA, will provide longhaul STS-3 (155.54 Mb/s) and STS-12 (622.08 Mb/s) pointto-point and point-to-multipoint full-duplex services over NASA's Advanced Communications Technology Satellite (ACTS). Data multiplexing over the satellite will be accomplished using TDMA techniques coordinated with the switching and beam hopping facilities provided on-board the ACTS. Transmissions to the satellite will be protected using Reed-Solomon encoding, providing almost error-free clearsky transmissions and, in the case of rain-fade, bit error rates better than 10-11 99.0% of the time. Unique to the system architecture are a TDMA frame structure and satellite synchronization mechanisms that, together, will allow (1) very efficient utilization of the satellite capacity, (2) over-the-satellite closed-loop synchronization of network configurations with up to 64 earth stations, and (3) earth station initial acquisition without collisions with existing signaling or data traffic. The end-user interfaces will use fiber-optics and will be compatible with SONET standards for fiber-based terrestrial networks. The terrestrial interfaces at the earth stations will perform the function of conventional SONET multiplexers and, as such, can be readily integrated with standard SONET fiber or radiobased terrestrial networks. As SONET multiplexers in the SONET hierarchy, the earth stations will synchronize the geographically-separated end-user interfaces. This synchronization will be implemented by terminating the section and line overheads of the SONET frames at the transmitting end of each satellite link, by transporting the payloads plus payload-pointer-bytes over the satellite, and by regenerating the SONET frames and corresponding section and line overheads at the receiving ends of the satellite links. Management of the network will be based upon the Internet Protocol (IP), including an over-the-satellite signaling network and backup terrestrial IP-based connectivity.