() switching was invented in the late 1960s for data communications.

A．Frame

B．Link

C．Packet

D．Line

[单选题]（）switching wasinvented in the late1960s for data communications.A.FrameB.L

[名词解释] Switching交换

[单选题]A．) still lateB．) too lateC．) so lateD．) past

[试题]C．ircuit Switching is problematic because data communications is（），that is， it is typically dominated by short bursts of activity with long periods of（）.A．reliable B．bursty C．digital D．continuous A．latency B．transmission C．delay D．inactivity

[单选题]Packet-switching wireless networks are preferable(66)when transmissions are(67)bemuse of the way charges are(68)per packet. Circuit-switched networks are preferable for transferring large files or for other lengthy transmissions because customers are

[单选题]Packet-switching wireless networks are preferable(41)when transmissions are(42)because of the way charges are(43)per packet. Circuit-switched networks are preferable for transferring large files or for other lengthy transmissions because customers ar

[单选题]Packet switching is a method of slicing(71) messages into parcels called "packets," sending the packets along different communication(72) as they become available, and then reassembling the packets(73) they arrive at their destination. Prior to the

[单选题]Circuit-switching technology is used in Publish Switched Telephone Network(PSTN), Global System for Mobile Communications(GSM) and code Division Multiple Access (CMDA) . It is a ( ) information transfer mode.A . connection orientedB . connectionles

[单选题]SDLC was invented by IBM to replace the older Bisynchronous protocol for wide area connections between IBM equipment ．A varietion of the (71) protocol called NRM is essentially the same as SDLC．SDLC is (72) protocol like HDLC , Frame. Relay or X．25．A

[单选题]SDLC was invented by IBM to replace the older Bisynchronous protocol for wide area connections between IBM equipment . A varietion of the (71) protocol called NRM is essentially the same as SDLC. SDLC is (72) protocol like HDLC, Frame. Relay or X.25.