《Computer network》Midterm Examination Name: Student number: 100min I.Choice.1．The ( ) is a worldwide computer network, that is, a network that interconnects millions of computing devices throughout the world.A InternetB IntranetC switch netD television net2．The units of data exchanged by a link-layer protocol are called ( ).A FramesB SegmentsC DatagramsD bit streams 3．( ) means that the switch must receive the entire packet before it can begin to transmit the first bit of the packet onto the outbound link.A Store-and-forward transmissionB FDMC End-to-end connectionD TDM4．In the following options, which one is not a guided(有线) media? ( )A twisted-pair wireB fiber opticsC coaxial cableD satellite5．Delay does not include ( ).A Process delayB propagation delayC transmission delayD controldelay6. In the following options, which belongs to the network core? ( )A end systemsB routersC clientsD servers7．The Internet’s connection-oriented service has a name, it is ( ).A TCPB UDPC TCP/IPD IP8．There are two fundamental approaches to building a network core, ( ) and packet switching.A electrical current switchingB circuit switchingC data switchingD message switching9．A ( ) protocol is used to move a datagram over an individual link.A application-layerB transport-layerC network-layerD link-layer10．Which of the following protocols is not a link-layer protocol? ( )A EthernetB PPPC HDLCD IP11．Consider CRC error checking approach, the four bit generator G is 1011, and suppose that the data D is 10101010, then the value of R is( ).A 010B 100C 011D 11012．The ARP protocol can translate ( ) into ( ). ( )A h ost name, IP addressB h ost name, MAC addressC I P address, MAC addressD broadcast address, IP address13．In the following descriptions about MAC address, which one is not correct? ( )A T he MAC address is the address of one no de’s adapter.B N o two adapters have the same MAC address.C T he MAC address doesn’t change no matter where the adapter goes.D M AC address has a hierarchical structure.14．In CSMA/CD, the adapter waits some time and then returns to sensing the channel. In the following four times, which one is impossible? ( )A 0 bit timesB 512 bit timesC 1024 bit timesD 1028 bit times 15．The most common Ethernet technologies are 10BaseT and 100BaseT. “10” and “100” indicate( ).A the maximum length between two adaptersB the minimum length between two adaptersC the transmission rate of the channelD the transmission rate of the node16．The principal components of PPP include but not( ).A framingB physical-control protocolC link-layer protocol Dnetwork-layer protocol17．In the following four options, which service can not be provided by switch? ( )A filteringB self-learningC forwardingD optimal routing18．In ( ) transmission(s), the nodes at both ends of a link may transmit packets at the same time.A full-duplexB half-duplexC single-duplexD both full-duplex and half-duplex20．MAC address is ( ) bits long.A 32B 48C 128D 6421．The following protocols are belonging to multiple access protocols except for ( ).A channel partitioning protocolsB routing protocolsC random access protocolsD taking-turns protocols22．Which of the following is not belonging to channel partitioning protocols? ( )A CSMAB FDMC CDMAD TDM23．( ) provides a mechanism for nodes to translate IP addresses to link-layer address.A IPB ARPC RARPD DNS24．A MAC address is a ( )address.A physical-layerB application-layerC link-layerD network-layer 35．Which of the following is correct? ( )A No two adapters have the same MAC address.B MAC broadcast address is FF-FF-FF-FF-FF-FF.C A portable computer with an Ethernet card always has the same MAC address, no matter where the computer goes.D All of the above36．In the Ethernet frame structure, the Data field carries the ( ).A IP datagramB segmentC frameD message37．Ethernet’s multiple access protocol is ( ).A CDMAB CSMA/CDC slotted ALOHAD token-passing protocol 38．A switch is a( )device that acts on frame.A physical-layerB link-layerC network-layerD transport-layer39．What are the two most important network-layer functions in a datagram network? （）A.forwarding & routingB.forwarding & filteringC.routing & detectingD.routing & checking40．A router forwards a packet by examining the value of a field in the arriving packet’s header, and then using this value to index into the router’s forwarding table, this value is? （）A.destination IP addressB.source IP addressC.destination MAC addressD.source MAC address41．Which layer provides host-to-host services? （）A.transport networkB.data link physical42．IPV4 has a ___ bit address? （）A.48 16B.32 6443．How many bits specify the IP protocol version in a datagram? （）A. 1 bitB. 2 bitsC. 4 bitsD.8 bits44．Data-grams are rarely larger than ____?（）A.1500 bytesB.65535 bytesC.500 bytesD.1024 bytes45．How does the TTL changed by one each time the datagram is processed by a router? （）A.decreaseB.increaseC.no changeD.always 046．ICMP is used for____?（）A.Reliable data transferB.Error reportingC.Flow controlD.Congestion control47．IP addressing assigns an address to 223.10.198.250/29, the network address for this network is____.（）A.223.10.198.248B.223.10.198.250C.223.10.198.0D.223.10.0.048．A switch works in ____ layer? （）workingB.Data linkC.ApplicationD.Physical49．The internet’s network layer provides a single service----that is ____.（）A.Reliable data transferB.Flow controlC.Congestion controlD.Best-effort-service50．Which of the following protocol is used for error reporting? （）A.ICMPB.TCPC.IPD.UDP51．Which of the following is not a routing protocol? （）A.TCPB.RIPC.OSPFD.BGP52．IP address is identifier for ____. （）A.HostB.Router interfaceC.Both of aboveD.None of above53．“233.1.1.0/24”, where the /24 notation, sometimes known as a____. （）A.Subnet maskworking addressC.Host addressD.None of above54．IPV6 has a ___ bits address? （）A.32B.64C.16D.12855．Which of the following is not intra-AS routing protocol? （）A.RIPB.OSPFC.IGRPD.BGP56．RIP is a kind of ____ algorithm. （）A.DVB.LSC.Both of aboveD.Neither of A and B57．OSPF is a kind of ____ algorithm. （）A.DVB.LSC.Both of aboveD.Neither of A and B58．The two important network-layer functions are ____. （）A.multiplexing and de-multiplexingB.routing and forwardingC.lookup and forwardingD.routing and IP addressing59．Suppose one IP datagram of 5,000 bytes (20 bytes of IP header) and it must be forwarded to a link with an MTU of 1,500 bytes, the offset and flag of the second fragment in header are ____. （）A.185, 0B.185, 1C.370, 1D.370,060．Given the IP address 202.96.104.8/20, its subnet address is ____. （）A.202.96.104.0B.202.96.96.0C.202.96.104.255D.202.96.111.25561．If the subnet mask is 255.255.240.0, then how many bits indicate the host address? （）A.20B.24C.12D.1662．Given the IP address 202.96.104.8/20, its broadcast address is ____. （）A.202.96.104.0B.202.96.96.0C.202.96.104.255D.202.96.111.255。