is a protocol that a host uses to inform. a router when it joins or leaves an Internet

multicast group.

(67)is an error detection code that most data conlmunication networks use.

(68)is an interior gateway protocol that uses a distance vector algorithm to propagate routing information.

(69)is a transfer mode in which all types of information are organized into fixed form. cells on an asynchronous or nonperiodic basis over a range of media.

(70)is an identifier of a web page.

A．ICMP

B．SMTP

C．IGMP

D．ARP