ABSTRACT
Figure 8.2 depicts the same “intranet” application as Figure 8.1, but where terrestrial links are substituted with satellite-based links; in this case, all links are substituted, but the routers use
some terrestrial links to reach the teleport location of a service provider, thereby obviating the need for satellite antennas at the customer location. Figure 8.3 depicts an example of a basic “intranet” application also with Internet access where terrestrial links are substituted with satellite-based links; in this case, all links are substituted and all locations have satellite antennas. Figure 8.4 shows a case where some links are replaced with satellite links, but others use terrestrial links. This could be the case when some routers are in one continent and the other routers are in another continent, or in the case where some routers are on the East Coast of the United States and the other routers are on the West Coast. Figure 8.5 depicts a future environment where routing decisions can be made (more efficiently) at the satellite level; this technology may become prevalent in the next decade. As an example in this arena, on March 29, 2007, a Cisco Systems router, flying in low Earth orbit onboard the UK-DMC satellite built by Surrey Satellite Technology Ltd (SSTL), was successfully configured by NASA Glenn Research Center to use IPSec and IPv6 technologies in space.
