Network Architectures to Improve the Performance of the Transport Layer in Satellite Communications

The paper began proposing two possible frameworks where the different solutions to improve the performance of the transport layer over satellite channels may be classified: the Black Box (BB) approach and the Complete Knowledge (CK) approach. The former implies that only the end terminals may be modified; the rest of the network is considered non-accessible (i.e. a black box). The latter allows tuning parameters and algorithm of the network components. Most of the previous research has been based on the Black Box approach. The advantages that derive from both the approaches are utilised to design a novel network architecture suited for satellite transportation, where the transport layer is divided into two parts, one of them completely dedicated to the satellite portion of the network (Satellite Transport Layer STL). The two components of the transport layer are joined by Relay Entities, which imply a complete redefinition of the protocol stack on the satellite side (Satellite Protocol Stack SPS). The new Satellite Transport Layer, based on the CK philosophy, will use a specific Satellite Transport Protocol (STP), obtained by a parameterisation, based on the TCP (Transmission Control Protocol), to meet all the network requirements and characteristics in terms of delay, reliability and speed. The Satellite Protocol Stack will operate also at the network layer and will benefit from possible resource allocation features of the layer 2 (data link) and, in particular, of the MAC (Medium Access Control) sub-layer. The paper presents some results, aimed at showing the performance that the new architecture can provide. The results have been obtained in a real satellite test-bed by using a simplified architecture, aimed at emulating the SPS.