Abstract: The launch of regional GEO multimedia satellites will initially support an Internet over satellite service in a star network configuration interconnecting users to an ISP. While a star network is ideally suited as an access technology for the bulk of Internet traffic including web browsing and email, the increasing need to support mesh networking for other applications is expected in the future. These applications include conferencing and business to business (B2B) eCommerce. For a GEO satellite in particular, this requires an on‐board processor to support single hop interconnectivity between small low cost terminals. This approach achieves the following advantages compared to a star configuration, which would require a double hop: (1) it minimises the latency by reducing the roundtrip delay in half; (2) it halves the capacity utilized; and (3) it provides signal regeneration, additional coding gain and switching. In general, some form of switching is required to interconnect beams in a multi‐beam system, typical of regional multimedia satellites which employ high gain spot beams to increase link margin and frequency reuse. In this paper the architecture and operation of the EMS SpaceMuxTM on‐board processor is described which achieves these objectives for mesh networking. The first generation of SpaceMuxTM supports the DVB‐RCS air interface and will operate as a demonstration of OBP mesh networking technology on the Telesat Anik‐F2 satellite due to be launched in the third quarter of 2002.