TCP协定靠得住性数据传输完成事理剖析(国外英文资料).docVIP

TCP协议可靠性数据传输实现原理分析(国外英文资料) Follow the data request at any time. At the end of the communication channel, it is possible to know if the number of the locally sent has been fully received; In addition the other reply serial number in the local data flux control also play an important role: from local to send serial number minus the other reply serial number can immediately know the sent data how many didnt get the other persons response. To sum up, the reliability transfer requires that both parties maintain the following serial Numbers: Snd. NXT the next serial number that will be sent locally. This variable corresponds to the sequence number field in the TCP header. The serial number of the first byte of the data contained in the packet. Each time a packet is sent, the variable needs to be updated: SND. NXT = snd.nxt + the data length contained in the packet sent this time is SND Each other to send data to the local so far has carried on the response of the serial number, in other words, SND. ACKED + 1 said local sent out but has yet to receive the other response data set corresponding to the first (minimum) serial number. The next serial number that rct.nxt is expected to receive. The serial number is called reply serial number, can also be called the request serial number, in the local delivery reply message, reply serial number field in a TCP header is set to the value of the variable, said local hope from the other party to receive the serial number of the next byte. Figure 1 (above) shows the TCP header format. The serial number field corresponds to the previous article snd. NXT variable, and the reply sequence number field corresponds to the previous post rcc.nxt variable. The ACK mark bit is set to 1 to indicate that this is a reply packet. In fact for the TCP protocol, after a successful connection is established, then send all the packets of ACK flag bit is set to 1, namely in the transmission of normal data at the same time response, so treatment can redu