TCP/IP 详解 卷1 ch17 TCP: Transmission Control Protocol

1. TCP provides a connection-oriented, reliable, byte stream service.

 

2. TCP lacks selective acknowledgments because the acknowledgment number in the TCP header means that the sender has successfully received up through but not including that byte.

 

3. flags

URG - urgent pointer

ACK - 确认序号有效

PSH - 接收方应尽快把这个报文交给应用层

RST - 重建连接

SYN - 同步序号用来发起一个连接

FIN - 发送端完成发送任务

 

4. 校验和包括TCP首部和TCP数据