(63)A．{0，0} B．{127，主机号} C．{10，主机号} D．{192，-1}
(64)A．{0，0} B．{128，主机号} C．{10，主机号} D．{168，-1}
(65)A．十六 D．十 C．八 D．二
● For each blank, choose the best answer from the four choices and write down on the answer sheet.
__(66)__ 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 communication 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 non-periodic basis over a range of media.
__(70)__ is an identifier of a web page.
(66)A．ICMP B．SMTP C．IGMP D．ARP
(67)A．4B/SB B．CRC C．Manchester Code D．Huffman Code
(68)A．OSPF B．RIP C．RARP D．BGP
(69)A．ISDN B．X.25 C．Frame Relay D．ATM
(70)A．HTTP B．URL C．HTML D．TAG
●In the following essay, each blank has four choices. Choose the best answer and write down on the answer sheet.
Spread spectrum simply means that data is sent in small pieces over a number of the __(71)__ frequencies available for use at any time in the specified range. Devices using __(72)__ spread spectrum (DSSS) communicate by __(73)__ each byte of data into several parts and sending them concurrently on different __(74)__ . DSSS uses a lot of the available __(75)__ , about 22 megahertz (MHz).
(71)A．continuous B．high C．low D．discrete
(72)A．direct-sequence B．discrete-sequence
C．duplicate-sequence D．dedicate-sequence
(73)A．splitting B．combining C．packing D．compacting
(74)A．bits B．frequencies C．packets D．messages
(75)A．rate B．velocity C．bandwidth D．period
|
