Satellites are used as links between earth-based networks. They are able to provide direct communication over large distances between any points around the world without the need to use of tangible wires. They are also able to bypass the congested lines of internet service providers and telephone companies. With the greater power of satellite transponders, satellites are able to offer bandwidth speeds of up to 155 Mbit/s. Thanks to such high speeds, companies can use high bandwidth applications, including streaming video or data and webcasting. Since there are no cables between links, information can be sent to the most remote areas of the world.
Satellites can be configured in different ways. If it is a bent pipe principle, then the uplink is concatenated with the downlink at the satellite in order to form a single communication channel between the source and final destination. The satellite sort of “reflects” the original message back to a certain place on earth. Although it is the simplest configuration, it is associated with a high risk of problems. Power requirements, antenna size, and atmospheric factors could cause problems with attenuation.
The second configuration is the OBP (on board processing). This involves a network of satellites connected with each other by intersatellite links. These links, or ISLS, use at least 60 GHz frequencies and operate at speeds of more than 1 Gbit/s. In this way, information is sent from earth to the satellite. The satellite does not reflect the data back down to earth but processes it. It includes error correction, signal regeneration, and routing.
An Ethernet topology allows to send out information to the whole network on the destination, but only the destination address will read it and reply. Satellites are not able to know the addresses of the entire internet. It only knows the information of other satellites and the stations served on earth. Since satellites are constantly changing their position, the stellar network is at times considered an autonomous routing system, and that is why the border gateway protocol is used between satellites and the earth. The satellite networks with ISLS, OBP, and spot beam antennas have lots of advantages, including efficient multicast routing, greater bandwidth capabilities, and on-demand dynamic resource allocation.
Transmission control protocol (TCP) provides a reliable transport of information across networks. In order to confirm that the information has been delivered, acknowledgements are sent to the senders.
Satellites are used as links between earth-based networks. They are able to provide direct communication over large distances between any points around the world without the need to use of tangible wires. They are also able to bypass the congested lines of internet service providers and telephone companies.