专门为单位或个人进入因特网提供产品和服务的公司英文简称为

A.ICP                                                         

B.ISP

C.IMP                                                         

D.NCC

采用一个码元取8种离散状态的移相键控PSK方法，若码元速率为1200波特，则可获得的数据传输速率为

A.1200bps                                                   

B.2400bps

C.3600bps                                                   

D.4800bps

物理层传输的数据单位是

A.包                                                           

B.比特

C.帧                                                           

D.数据块

TCP协议的主要功能是

A.分配IP地址                                            

B.提供端到端的面向连接的可靠数据传输

C.确定数据传输路径                                   

D.提高传输速度        

下列协议中运行在应用层的协议是

A.IP                                                           

B.ARP

C.TCP                                                         

D.DNS