Research And Implementation Of TCP Timing Mechanism For TOE Network Card

With the enlargement of the network size and Sharp increase of the network traffic,the network bandwidth is higher and higher,and only high bandwidth network can meet the need for ever increasing information flow. All the time, TCP/IP is all realized inside the host operating system, With the rapid growth of the bandwidth of the network, greater and greater the host computer CPU performance were consumed, the expenses of dealing with TCP protocol suite have already become the bottleneck in whole performance of the host computer system.TOE technology is to adopt hardware to realize TCP/IP, and obtains the greatest performance to promote , It transfers some or all functions of TCP/IP to network card to realize ,and seamlessly connect with the host operating system , and it is compatible with already exsit application programs , the network card using this kind of technology is called the TOE net card (TNIC) .In the realization of the TOE net card, TCP timing mechanism have important influence definitely on network performance . from the beginning of establishing a TCP connect using the three step handshake procedure until the end of canceling the connect, the participation of TCP timers is required in the whole process. So that the TCP timing mechanism in a TOE net card is definitely important. Only The correct work of the TCP timing mechanism can guarante the normal running of TCP agreement.In addition, TOE net acrds are usually used in the high perfermance end severs in a high speed network environment. So, the TCP timing mechanism in a TOE card is to some extent different from that we commonly used before. For example, if we still use the the commonly used TCP timing mechanism without any enhances, the network will to some extent become to be more congested, to counteract this, Am improved self adaptive RTO estimte algoritm is presented in this thesis. The algoritm was simulated using the ns2 simulation tool, and the performance promotion over the commonly used TCP retransmission timer is verified.