B. Presentation, session, and data link
C. Session, network, and physical
D. Presentation, data link, and physical
14) What is a socket in the transport layer (传输层中的套接字是什么)?
A. The socket is an IP address plus a port
B. An API that makes the transport layer independent
C. An API that allows multiple applications to share a network connection
D. A function that makes remote procedures appear to be local
15) What is a port (什么是端口)?
A. An API that makes the transport layer independent
B. An API that allows multiple applications to share a network connection