表23.2TCP使用的熟知端口 Port Protocol Description 2 Echo Echoes a received datagram back to the sender 9 Discard Discards any datagram that is received 11 Users Active users 13 Daytime Returns the date and the time 17 Quote Returns a quote of the day 19 Chargen Returns a string of characters 20 FTP.Data File Transfer Protocol(data connection) 21 FTP,Control File Transfer Protocol(control connection) 23 TELNET Terminal Network 25 SMTP Simple Mail Transfer Protocol 53 DNS Domain Name Server 67 BOOTP Bootstrap Protocol 79 Finger Finger 80 HTTP Hypertext Transfer Protocol 111 RPC Remote Procedure Call 23.26
23.26 表 23.2 TCP使用的熟知端口
图23.13字节流传递 Sending Receiving process process Stream of bytes TCP TCP 23.27
23.27 图 23.13 字节流传递
图23.14发送和接收缓冲区 Sending Receiving process process TCP TCP Next byte Next byte to write to read Buffer Buffer Sent Not sent Not read Next byte Stream of bytes Next byte to send to receive 23.28
23.28 图 23.14 发送和接收缓冲区
图23.15TCP段 Sending Receiving process process TCP TCP Next byte Next byte to accept to deliver Buffer Buffer Sent Not sent Not read Segment N Segment 1 Next byte 四四H 000H Next byte to be sent to receive 23.29
23.29 图 23.15 TCP段
注意 在每个连接中传送的字节都由TCP编号，序 号开始于一个随机产生的数。 23.30
23.30 在每个连接中传送的字节都由TCP编号，序 号开始于一个随机产生的数。 注意