网工英语10套练习题

  

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 automatically (4) and entered into the order fields across merchant sites.Consumers also benefit when using digital wallets because their information is (5) or protechted a private software code.And merchants benefit by receiving protection against fraud.

 

(1) A.software  B.hardware C. device  D.document

(2) A.cards     B.secrets  C.public information D.person information

(3) A.distributed B. stored C.addressed  D.registered

(4) A.coded       B.updated C.corrected  D.named

(5) A.encrypted   B.updated C.secured    D.undiscovered

答案:1:A,2:D,3:B,4:B,5:A

 

The router inspecters the packet’s IP address and performs (1) lookup to see if the destination end station resides on the local (physically connected) network,typically called an IP subber (2) usually is assignted to each of the router’s network interface.If

the destination IP address is local,the router searches an internal store of IP address and local-device Media Acess Control(MAC) address.This store is known as  the (3) cache. Address Resolution Protocol(ARP)is the universal tool for matching IP addresses to MAC address.If the destination’s MAC address appears,the router installs that MAC address in the pachet header(removing its own MAC address because that’s no longer needed) and sends the packet to the destional end station.

   In the event that the destional MAC address does not appear in the ARP cache-it might have timed out,for instance-the router must broadcast an ARP request to the subnet referenced by the packet’s destional IP address.The end station with that IP address responds, sending back its MAC address. The router updates its cache,installs the new MAC address into the(4) and launches the packet. If the router table lookup shows that the packet is destined for a non local subnet,the router forwards the packet to the next-hop  router using the-hop router’s MAC address.Routing tables are continuously built and rebuilt by intelligent discovery protocols,such as Routing  Information Protocol or Open Shortest Path First(OSPF).Each router’ s routing table shows the best route to the destination address:for address that may be severd hops away,it shows(5) next-hop router.

 

(1) A. a router table  B.a signal C.an e-mail D.a file

(2) A. A TCP  subnet    B.IP headerC. An IP subnet     D.TCP/IP

(3) A.OSPF     B. Address Resolution Protocol(ARP)C.MAC      D.RIP

(4) A.small packet      B.space     C.packet header  D.packet tailor

(5) A.the fewest        B.the worst C.the least      D.the best

答案:1:A,2:C,3:B,4:C,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 the Runnel .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)__,which Verify 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

 

Bluetooth is a universal radio interface in the __(1)__frequency band that enables portable electronic devices __(2)__ connect and communicate __(3)__via short range,ad hoc net Works .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 th support of Nokia,IBM,Toshiba,Intel and many other manufactures,eliminates ths need for wires,cables and connectors for and between cordless or mobile phones,modems,headsets,PDAs,Computers,printers.projectors,local area 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. 1.45GHZ

(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