计算机网络-第二次平时考试

计算机网络平时考试试题（带答案）一、选择题1．In the Ethernet frame structure, the Data field carries the ( ).A.IP datagramB.segmentC.frameD.message2．The units of data exchanged by a link-layer protocol are called ( ).A. FramesB. SegmentsC. DatagramsD. bit streams3．The SYN segment is used for ( ).A.TCP connection setupB.TCP flow controlC.TCP congestion controlD.Closing a TCP connection4．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 net5．The units of data exchanged by a link-layer protocol are called ( ).A. FramesB. SegmentsC. DatagramsD. bit streams6．In Address：,（）indicates “host name”.A. wwwB. uzzC. eduD. cn7. In the following options, which belongs to the network core? ( )A. end systemsB. routersC. clientsD. servers8．The Internet’s connection-oriented service has a name, it is ( ).A.TCPB. UDPC.TCP/IPD.IP9．There are two fundamental approaches to building a network core, ( ) and packet switching.A. electrical current switchingB. circuit switchingC. data switchingD. message switching10．A ( ) protocol is used to move a datagram over an individual link.A. application-layerB. transport-layerC. network-layerD. link-layer 11．Services provided by transport layer include ( ).A.HTTP and FTPB.TCP and IPC.TCP and UDPD.ICMP12．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. 223.10.0.013．IP belongs to ( ).layer?A.transportworkC.data linkD. physical14．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 above15．How many bits specify the IP protocol version in a datagram? ( ).A.1 bitB.2 bitsC.4 bitsD.8 bits16．In the following applications, which one is a loss-tolerant application?A E-mailB file transferC instant messagingD real-time audio 18．The Internet mail system has three components which they are ( ).er agent, SMTP, POP3B.SMTP, POP3, IMAPer agent, SMTP, IMAPer agent, SMTP, mail server19．DNS means ( ).A.Data Name SystemB.Data National SystemC.Domain Name SystemD.Domain National System20．“233.1.1.0/24”, where the /24 notation, sometimes known as a ( ).A. Subnet maskB. Networking addressC. Host addressD. None of above 21．Which of the following is not intra-AS routing protocol? ( )A. RIPB. OSPFC. IGRPD.BGP22．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. 223.10.0.023．IP Data-grams are rarely larger than ( ).A. 1500 bytesB. 65535 bytesC.500 bytesD.1024 bytes 24．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 above25．Which of the following is not belonging to channel partitioning protocols? ( )A.CSMAB.FDMC.CDMAD. TDM26. MAC address is ( ) bits long.A.32B.48C.128D.6427．The Internet’s connection-oriented service has a name, it is ( ).A.TCPB.UDPC.TCP/IPD.IP28．In the LAN, ( ) protocol dynamically assign IP addresses to hosts.A.DNSB.ARPC.DHCPD.IP29．Which layer provides host-to-host services? ( ).A. transportB. networkC. data linkD. physical30．DHCP protocol is a four-step process: ①DHCP request. ②DHCP ACK. ③DHCP server discovery. ④DHCP server offer(s). The correct sequence is ( )A.①②③④B.③②①④C.③④①②D.①④③②31．In the Ethernet frame structure, the CRC field is ( ) bytes.A.2B.4C.8D.3232．Transport-layer protocols run in ( ).A.ServersB.ClientsC.RoutersD.End system33．The maximum amount of data that can be grabbed and placed in a segment is limited by the( ).A. Maximum segment size (MSS)B. MTUC. ChecksumD. Sequence number 34．The internet’s network layer provides a single service----that is ( ).A. Reliable data transferB. Flow controlC. Congestion controlD.Best-effort-service35．There are 6 flag fields. Which one is to indicate that the receiver should pass the data to the upper layer immediately? ( )A. PSHB. URGC. ACKD. RST36．ICMP is used for ( ).A. Reliable data transferB. Error reportingC. Flow controlD.Congestion control37．The FIN segment is used for ( ).A. TCP connection setupB. TCP flow controlC. TCP congestion controlD. Closing a TCP connection38．A transport-layer protocol provides for logical communication between ( ).A. Application processesB. HostsC. RoutersD. End systems 39．Port number’s scope is ( ) to ( ).A. 0, 1023B. 0, 65535C. 0, 127D. 0,25540．“233.1.1.0/24”, where the /24 notation, sometimes known as a( ).A. Subnet maskB. Networking addressC. Host addressD. None of above二、判断题1．In CSMA/CD, one node listens to the channel before transmitting. T2．In C/S architecture, client has a fixed well-known address. F3．In P2P architecture, peers communicate with each other directly. T4．Each TCP connection is closed after the server sending one object.5．There are four steps in DHCP, the DHCP server can complete DHCP response.F6．In full-duplex transmission(s), the nodes at both ends of a link may transmit packets at the same time. T7．DNS resolves hostnames for hosts anywhere in the Internet. T8．ARP resolves an IP address to a MAC address. T9．In the broadcast packet of DHCP DISCOVER，source IP address is 0.0.0.0. T10．The routing algorithm running within an autonomous system is called an intra-AS routing protocol. F11．In CSMA/CD, one node listens to the channel before transmitting. TT12．All of the Ethernet technologies provide connection-oriented reliable service to the network layer.F13．A router receives a packet, in which TTL=0, and the packet will be dropped. T14. Datagram networks are circuit-switched networks, and virtual-circuit networks are packet-switched networks.F15．ARP resolves an IP address to a MAC address. T16．If the traffic intensity is close to zero, the average queuing delay will be close to zero. T17．A router receives a packet, in which TTL=0, and the packet will be dropped. T18．The adapter is also called as NIC. T19．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 010. F20．Hubs can interconnect different LAN technologies. F三、填空题1. Common Channel multiplexing technology includes _FDM_、_TDM_、_WDM_、__CDM__. 2．NIC works in _data link_ layer of Internet.3. __network_ layer provides host-to-host services, and _transport_ layer providesprocess-to-process services.4．MAC address is _48_ bits, and IPV4 has a 32_ bit address.5．The data transmission delay include: _propagation delay_、__transmission delay_、processing delay and queuing delay.6．The port number used by HTTP is _80_；The port number used by SMTP is _25_；The port number used by DNS is _53_.7．在TCP连接建立过程中，客户端向服务器发送一个连接请求的TCP报文，其中包含连接的初始序列号v和一个窗口大小，服务器收到报文后，向客户端发送一个请求确认的报文，其中包含它选择的初始序列号w．确认号为_V+1_，和一个窗口大小。