Among the network devices used for high performance parallel computing, Myrinet and Gigabit-Ethernetare relatively more widely applied. The modification in architecture and communication method has brought to greatimprovement of network based on Myrinet and Gigabit Ethernet. In this paper, we analyze major features of TCP/IPprotocol, point out the restrictions of TCP/IP protocol over high speed network and propose some methods to en-hance the performance.