软考网络工程师资料-网工英语10套练

网工英语10套练习题

ISDN,which stands for Integrated Services Digital Network, is a

system of digital phone connections, which has been available for

over a decade.This system allows data to be transmitted

simultaneously across the world using (1) digital connectivity.With

ISDN,voice and data are carried by bearer channels occupying a

bandwith of (2) (bits per second).Some switches limit B channels to

capacity of 56 Kbps.A data channel (3) handles signaling at 16Kbps

or 64Kbps,depending on (4) .Note that,in ISDN terminology,”k”

means (5),and not 1024(2^10) as in many computer

applications;therefore,a 64Kbps channel carries data at a rate of

64000bps. A new set of standard prefixes has recently been created

to handle this. Under this scheme,”K”(Kilo) means 1000(10^3),”M”

(Mega) means 1000000(10^6),and soon ,and “Ki”(Kibi) means 1024

(2^10),”Mi” (Mebi) means 1048576(2^20).and soon。

(1). A.Multi-ends B.circle C.indirect D.end-to-end (2). A.34 Kbps B. 84 Kbps C. 64 Kbps D. 54 Kbps (3). A.D channel B.A channel C.B channel D.C channel

(4). A.the method B.the number C.the service type D.the user type (5). A.100000(10^5) B.1000(10^3) C.10000(10^4) D.100(10^2)

答案:

1:D,2:C,3:A,4:C,5:B

Bluetooth is a universal radio interface in the (1) frequency band

that enables portable celectronic devices (2) connect and

communicate (3) via short range,ad hoc networks.Each unit can

simultaneously communicate with up to (4) other units per piconet.

Moreover,each unit can simultaneously (5) to several

piconets,Bluetooth technology which apart from Ericsson,has gained

the support of Nokia,IBM,Toshiba,Intel and many other

manufactures,eliminates the need for wires,cables and connectors

for and between cordless or mobile

phones,modems,headsets,PDAs,Computes,printers,progjectors,local

ares networks,and so on ,and paves the way for new and completely

different devices and applications.

(1). A.2.45GHz B. 4.45GHz C. 2.95GHz D. 3.45GHz (2). A.in B. on C. to D. with (3). A.narrowly B.wirelessly C.freely D.widely (4). A.use B.sever C.host D.base (5). A.relate B.add C.close D.belong 答案:1:A,2:C,3:B,4:B,5:D

(1)is used to ensure the confidentiality,integrity and authenticity

of the two end points in the private network .the(2),an application

layer protocol,authenticates each peer in an IPsec transaction ,IKE

negotiates security policy,determining which algorithm may be used

to set up theRunnel .It also handles the exchang of session keys

used for that one transaction.Networks that use (3)to secure data

traffic can automatically authenticate devices by using (4)

whichVerify the identities of the two users who are sending

information back and forth .IPsec can be ideal way to secure data in

large networks that require (5) connections among many devices。

(1) A.Encryption B.Code C.Certificate D. Tunnel

(2) A.associated links B.Internet Key Exchange C IPsec D. encryption (3) A authenticity B.password C.IPsec D. Internet Key Exchange (4) A.protocols B.keywords C.IKE D. digital certificates (5) A.free B.strict C.secure D.remote 答案:1:A,2:B,3:C,4:D,5:C

LAPB is a (1) protocol that provides complete data transparency in

a (2)operation. It supports a peer-to-peer link in that neither end

of the link plays the role of the permanent master station.

HDLC LAPB is the (3)that is usually used by(4), the (5)standard for

Packet Switched Networks.

(1)A．bit-oriented synchronous B．byte-oriented synchronous

C．bit-oriented asynchronous D．byte-oriented asynchronous (2)A．half-duplex point-to-point B．half-duplex point-to-points C．full-duplex point-to-point D．full-duplex point-to-points (3)A．Physical Layer B．Link Layer C．Network Layer D．Transport Layer (4)A．X.21 B．X.25 C．X.28 D．X.29

(5)A．ITU B．IEEE C．OSI D．ANSI 答案:1:A,2:C,3:B,4:B,5:A

Data communications equipment(DEC) (1) the serial data stream from

the DTE and converts it to some form of (2) suitable of

transmission on voice grade lines. At the (3),the DCE performs the

reverse function of convering the received analog signal to serial

digital data stream .The simplest form of DCE is a (4) or data set .

At the transmit end, the modem can be considered a form of (5),while

at the receive end, it can be considered a form of analog to

digital converter. The most common forms of modulation by modems are

frequency shift keying(FSK),phase shift keying(PSK) ,and quadrature

amplitude modulation(QAM). If the cables and signal levels used to

interconnect the DTE and DCE were left unregulated,the variations

generated would probably be proporation to the number of

manufactures. Electronics Industries Association(EIA) ,an

organization of manufactuuers concerned with establishing industry

standards,have agreed on the RS-232C as the standard interface

between the DTE and the modem .This is a 25 pin cable pins have

designated funtons and specified signal levels.

(1) A. accepts B.sends C.delivers D.receives (2) A. digital signal B.analog signal C.light signal D.sound signal (3) A. back end B.front end C.sending end D.receive end (4) A. modem B.cpu C.demodulator D.modulator. (5) A. host computer B.digital to analog converter C. analog to digital converter D.secondaries 答案:

1:A,2:B,3:D,4:A,5:B

In ATM,cells serve as universal units for all information

types:data,voice,video,etc,Since switches know beforehand the size

and format of each information unit sent through the network,switch

architectures can be (1),Futhermore ,since the CMS determines the

connection path during connection setup,switches do not have to make

complex routing decisions on a (2) basis.Communiciation paths can be

“hard wired” into the switch’s circuits to enable fast,simple

decisions. Hardware techniques,using VLSI based state machines

and ,in the future,optical switching techniques,can be applied to

switches.Hardware Based switch matrices take advantage of all these

(3) characteristics.The matrix approach to implementing cell

switching greatly increases the scalability of ATM based

solutions,One fundamental advantage of matrix based switches is

that,as more ports are added to the switching complex,the aggregate

switching capacity of the switch increases. In other words, as(4)

are added to a switched network, they tap into an increasing band

width pool-the complete opposite of shared media networks,where user

are forced to share smaller and smaller slices of a fixed amount of

(5).Simply put,cell switching based on ATM enables extremely

fast,massively scalable networdks.

(1) A.optimized B.increased C.decreased D.fixed (2) A.cell by cell B.object oriented C.bit-by-bit D.LAN

(3) A.VLSI B.OSI C.CMS D.ATM (4) A.cells B.switches C.users D.approaches (5) A.data B.media C.bandwidth D.information

答案:1:A,2:A,3:D,4:C,5:C

A digital wallet is (1) that enables users to pay for goods on the

web.It holds credit card numbers and other (2) such as shipping

address. Once entered, the data automatic ally populates order

fields at merchant sites. When using a digital wallet,consumers don’

t need to fill out order forms on each site when they purchase an

item because the information has already been (3) and is

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