Satellite network has some special characteristics, such as the big propagation delay, high bit-error rate and asymmetric channels, and these characteristics make TCP/IP protocols incapable of providing satisfying service for satellite network. The idea of cross-layer design can reduce the redundancy of multi-layer, and capture network status information at any moment. The protocol can set a window congestion gate-limit threshold more effectively by getting the available bandwidth information from the link layer. And in the link layer a router buffer queue managing mechanism is set to compute the network congestion probability and then feedback it to the sender. It can also differentiate the packet losses between congestion and link error to avoid reducing the send window unnecessarily. The protocol will use this information to regulate the size of window dynamically. The experiment shows the protocol greatly improved the transport performance of satellite networks.
