Eutelsat services for IP access

Satellite links are increasingly being used to boost the bandwidth to Internet service providers (ISP) from Western Europe and the US. The bandwidth required is often asymmetric or even one-way, with the greater traffic flow away from the US. This paper begins by describing such an application and then goes on to describe work done on routing protocols over satellite, firstly to assure ourselves that they work over satellite and secondly to measure their overhead. The classes of routing protocols are given and then each routing protocol is discussed. A table summarises the benefits and issues connected with each protocol. Finally, results are given of testing RIP, OSPF and BGP over a simulated satellite link. It is concluded that RIP is only suitable for small networks because RIP updates by sending the whole routing table every 30 seconds. OSPF can be used for larger networks as updates contain only network changes. However, OSPF is more complicated to set-up and requires more processing power than RIP. In practice, OSPF does not assign any particular weighting to a satellite link. The BGP works between autonomous systems, sends only incremental information and uses keep-alive packets every 60 seconds. Routes over a satellite delay were assigned, by default, weight 100 and routes over terrestrial link are assigned a weight of 0