One host can be running many network applications, so the system assigns them different ( ) to distinguish each other.
A. IP address
B. port number
C. hostname
D. section
The port number of the mail server is ( ).
A. 25
B. 20
C. 80
D. 8080
Look the URL http://www.djtu.edu.cn/rjxy/index.html, the object's path name is ( ).
A. www.djtu.edu.cn
B. www.djtu.edu.cn/rjxy
C. /rjxy/index.html
D. index.html
OSI/RM体系结构、TCP/IP体系结构、原理体系结构的分层数量分别为
A. 4,5,6
B. 5,6,7
C. 7,4,5
D. 7,6,5