Study on Methods for Constructing Layered Protocols in High-Speed Satellite Data Networks

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Satellite data networks can be used to meet an increasing demand that a large amount of information can be transmitted and exchanged at high speeds among many sites. One of the most important problems to be solved in the development of high-speed data networks is how to construct communication protocols. The objective of this project is to develop some methods for constructing efficient layered protocols in high-speed satellite data networks.We first make a performance comparison between a connection-oriented (CO) Logical Link Control (LLC) protocol and a connectionless (CL) LLC protocol in a high-speed satellite packet network with the TDMD-Reservation multiple access protocol. In particular, we examine how the channel transmission rate affects the peformance of the two LLC protocols and then determine which LLC protocol is more suitable for any given system environment. The comparison indicates that the CL-LLC protocol has more advantages over the CO-LLC protocol as the channel transmission rate increases and that the suitable region for the CL-LLC protocol becomes wider as the receive-buffer capacity increases and as the network load decreases.Next, we propose two methods for constructing the data link protocol satellite data networks : the isolated type and combined type. In the isolated type, a MAC protocol is defined independent of its LLC protocol, whereas the combined type has a MAC protocol related to its LLC protocol. We study here two MAC protocols, TDMA-Reservation and Slotted-ALOHA, and a connection-oriented LLC protocol. We compare the two methods and then see that the combined type with the TDMA-Reservation protocol always outperforms the corresponding isolated type, while the performance difference between the two types with Slotted-ALOHA is very small.In addition, we also study link-level connection control schemes in local area networks (LAN's) as a preliminary research on interconnecting LAN's by satellite links.