题目内容:
根据下面的文字资料回答题SDLC was invented by IBM to replace the older Bisynchronous protocol for wide atrea conneetions between IBM equipment.A varietion of the.( 1 )protocol called NRM is essentially the same as SDLC.SDLC is( 2 )protocol like HDLC,Frame Relay or X.25.An SDLC network is made up of( 3 )that controls all communications,and( 4 ),It is capable of ( 5 )operation,but almost all practical applications are strictly half duplex。文中( 1 )处正确的答案是( )。
A.HDLC B.Frame Relay
C.25
D.21
参考答案:
答案解析: