2022年2022年计算机网络题库chapter 3.pdf

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1、Chapter 4 The Network Layer 1What is the name of a network-layer packet?（）A.message B.segment C.datagram D.frame 2What are the two most important network-layer functions in a datagram network?（）A.forwarding&routing B.forwarding&filtering C.routing&detecting D.routing&checking 3When a packet arrives

2、at a routers input link,the router must move the packet to the appropriate output link,this action is called _?（）A.Forwarding B.routing C.cut through D.filtering 4The network layer must determine the path taken by packets as they flow from a sender to a receiver.This action is called_?（）A.Forwarding

3、 B.routing C.cut through D.examine 5 A router forwards a packet by examining the value of a field in the arriving packets header,and then using this value to index into the routers forwarding table,this value is?（）A.destination IP address B.source IP address C.destination MAC address D.source MAC ad

4、dress 6IP belongs to _ layer?（）A.transport B.network C.data link D.physical 7Which layer provides host-to-host services?（）A.transport B.network C.data link D.physical 8Which layer provides a connection service called virtual-circuit networks and a connectionless service called datagram networks?（）A.

5、transport 名师资料总结-精品资料欢迎下载-名师精心整理-第 1 页，共 14 页 -B.network C.data link D.physical 9IPV4 has a _ bit address?（）A.48 B.16 C.32 D.64 10MAC address is _ bits?（）A.48 B.16 C.32 D.64 11The Internets network layer has three major components,the first component is the IP protocol,the second component is the ro

6、uting protocol,the final component is_?（）A.forwarding B.address translation C.check D.ICMP 12How many bits specify the IP protocol version in a datagram?（）A.1 bit B.2 bits C.4 bits D.8 bits 13Most IPV4 datagram do not contain option field,how many bytes a header has in a typical IP datagram?（）A.4 by

7、tes B.8 bytes C.16 bytes D.20 bytes 14How many bits used in IP datagram express total length of the IP datagram?（）A.4 bits B.8 bits C.16 bits D.20 bits 15Data-grams are rarely larger than _?（）A.1500 bytes B.65535 bytes C.500 bytes D.1024 bytes 16New version of IP-IPV6 does not allow fragment in _?（）

8、A.Router 名师资料总结-精品资料欢迎下载-名师精心整理-第 2 页，共 14 页 -B.Host C.Both of above D.None of above 17How does the TTL changed by one each time the datagram is processed by a router?（）A.decrease B.increase C.no change D.always 0 18Which layer protocol is indicated by the value of protocol field in IP datagram?（）A.

9、application B.transport C.network D.data link 19IP option is dropped in the _ header.（）A.IPv6 B.IPv4 C.TCP D.UDP 20The data field in IP datagram can carry many types of data except _.（）A.TCP B.UDP C.ICMP D.MAC 21ICMP is used for_?（）A.Reliable data transfer B.Error reporting C.Flow control D.Congesti

10、on control 22Suppose you receive an IP datagram from one link and check your forwarding table to determine the outgoing link,but this outgoing link has an MTU that is smaller than the length of IP datagram.Which technology will be used?（）A.resend B.discard C.fragment D.none 23 The designer of IPv4 d

11、ecided to put the job of datagram reassembly in_.（）A.router B.switch C.hub D.end system 24IP addressing assigns an address to 223.10.198.250/29,the network address for this network is_.（）名师资料总结-精品资料欢迎下载-名师精心整理-第 3 页，共 14 页 -A.223.10.198.248 B.223.10.198.250 C.223.10.198.0 D.223.10.0.0 25If all data-

12、grams arriving at the router from WAN have the same destination IP address,then how does the router know the internal host to which it should forward a given datagram?The trick is to use _ table at router,and include port numbers as well as IP address in the table entries.（）A.routing B.forwarding C.

13、ARP D.NAT translation 26 When running a Telnet,FTP,or HTTP session,you may have encountered an error message such as“Destination network un-reachable”,This message had its origin in _.（）A.IGMP B.EGP C.ICMP D.BGP 27The well-known ping program sends an(a)_ type 8 code 0 message to the specified host.T

14、he destination hosts seeing the echo request,send back a type 0 code 0 ICMP echo reply.（）A.ICMP B.IGMP C.TCP D.UDP 28Tracer-out is implemented with _ messages.（）A.IGMP B.TCP C.UDP D.ICMP 29The standard Tracer-out program actually sends sets of _ packets with the same TTL.（）A.one B.two C.three D.four

15、 30IPv6 increases the size of the IP address from 32bit to _ bit.（）A.64 B.128 C.256 D.512 31How many bytes are there in header of IPv6?（）A.8 名师资料总结-精品资料欢迎下载-名师精心整理-第 4 页，共 14 页 -B.20 C.40 D.32 32 IPv6 does not allow for fragmentation and reassembly at inter-media _.（）A.routers B.switches C.end syste

16、m D.hubs 33 From sender to receivers,all packets will take the same path,this is we use a _ service.（）A.datagram B.VC C.circuit D.Ethernet 34_ means moving packets from routers input port to appropriate router output port?（）A.forwarding B.filtering C.routing D.switching 35_ means determining route t

17、aken by packets from source to destination?（）A.forwarding B.filtering C.routing D.switching 36A router works in _ layer?（）A.Networking B.Data link C.Application D.Physical 37A switch works in _ layer?（）A.Networking B.Data link C.Application D.Physical 38Networking layer provides services between two

18、 _.（）A.Hosts B.Processes C.Applications D.Machines 39Link layer provides services between two _.（）A.Hosts B.Processes 名师资料总结-精品资料欢迎下载-名师精心整理-第 5 页，共 14 页 -C.Applications D.Machines 40The internets network layer provides a single service-that is _.（）A.Reliable data transfer B.Flow control C.Congestio

19、n control D.Best-effort-service 41Datagram network provides network-layer_.（）A.connectionless service B.connection service C.both of above D.neither of A and B 42VC network provides network-layer _.（）A.connectionless service B.connection service C.both of above D.neither of A and B 43In VC network,e

20、ach packet carries _.（）A.VC identifier B.destination host address C.IP address D.Mac address 44A VC consists of three part,this three parts do not include_.（）A.Path from source to destination B.VC numbers,one number for each link along path C.Entries in forwarding tables in routers along path D.Dest

21、ination address 45.In _ networking,a series of packet may follow different paths and may arrive out of order?（）A.Datagram B.VC C.TCP D.None of above 46The internet is a(an)_ network?（）A.Datagram B.VC C.Both of above D.None of above 47The four components of a router do not include_?（）A.Input and outp

22、ut ports B.Switch fabric C.Routing processor D.Switching processor 48There are three kinds of switch fabric for a router normally,those three switch 名师资料总结-精品资料欢迎下载-名师精心整理-第 6 页，共 14 页 -fabric do not includes_?（）A.Switching via memory B.Switching via a bus C.Switching via an Interconnection-Network

23、D.Packet switching 49Which of the following protocol is used for error reporting?（）A.ICMP B.TCP C.IP D.UDP 50Which of the following is not a routing protocol?（）A.TCP B.RIP C.OSPF D.BGP 51IPV4 has a _ bits address?（）A.32 B.64 C.16 D.128 52IP address is identifier for _.（）A.Host B.Router interface C.B

24、oth of above D.None of above 53“233.1.1.0/24”,where the/24 notation,sometimes known as a_.（）A.Subnet mask B.Networking address C.Host address D.None of above 54Subnets with an 8-,_-,and 24-bit subnet addresses were know as class A,B,and C networks respectively.（）A.9 B.10 C.12 D.16 55IPV6 has a _ bit

25、s address?（）A.32 B.64 C.16 D.128 56_ means that IPv6 nodes also have a complete IPv4 implementation as well?（）A.Dual stack 名师资料总结-精品资料欢迎下载-名师精心整理-第 7 页，共 14 页 -B.Tunneling C.Bridge connection D.Forwarding 57_ means that IPv6 carried as payload in IPv4 data-gram among IPv4 routers?（）A.Dual stack B.Tu

26、nneling C.Bridge connection D.Forwarding 58Typically a host is attached directly to one router,the _ for the host.（）A.Default router B.Source router C.Destination router D.Core router 59The default router of the source host is known as _.（）A.Default router B.Source router C.Destination router D.Core

27、 router 60The default router of the destination host is known as _.（）A.Default router B.Source router C.Destination router D.Core router 61A path between the source and destination that has beast cost is known as_.（）A.Least cost path B.Shortest path C.Largest cost path D.None of above 62 The path wi

28、th the smallest number of links between the source and the destination is known as _.（）A.Least cost path B.Shortest path C.Largest cost path D.None of above 63Which of following about DV is not correct?（）A.Iterative B.Synchronous C.Distributed D.Self-terminating 64Which of the following is not intra

29、-AS routing protocol?（）A.RIP B.OSPF 名师资料总结-精品资料欢迎下载-名师精心整理-第 8 页，共 14 页 -C.IGRP D.BGP 65RIP is a kind of _ algorithm.（）A.DV B.LS C.Both of above D.Neither of A and B 66OSPF is a kind of _ algorithm.（）A.DV B.LS C.Both of above D.Neither of A and B 67The router in non-backbone areas and perform only i

30、ntra-AS routing is known as _.（）A.Internal routers B.Area border routers C.Backbone routers D.Boundary routers 68_“summarize”distances to nets in own area,advertise to other Area Border routers.（）A.Internal routers B.Area border routers C.Backbone routers D.Boundary routers 69_ runs OSPF routing lim

31、ited to backbone.（）A.Internal routers B.Area border routers C.Backbone routers D.Boundary routers 70_ connect to other ASs.（）A.Internal routers B.Area border routers C.Backbone routers D.Boundary routers 71Which of the following is an inter-autonomous system routing protocol?（）A.RIP B.OSPF C.IGRP D.

32、BGP 72_means sending a packet to all other nodes in the network.（）A.Broadcast B.Multicast C.Any-cast D.Uni-cast 名师资料总结-精品资料欢迎下载-名师精心整理-第 9 页，共 14 页 -73A _ packet is delivered to only a subset of network nodes.（）A.Broadcast B.Multicast C.Any-cast D.Uni-cast 74Means that the switch must receive the en

33、tire packet before it can begin to transmit the first bit of the packet onto the outbound link.（）A.store-and-forward transmission B.FDM C.End-to-end connection D.TDM 75Datagram networks and virtual-circuit networks differ in _.（）A.Datagram networks are circuit-switched networks,and virtual-circuit n

34、etworks are packet-switched networks.B.Datagram networks are packet-switched networks,and virtual-circuit networks are circuit-switched networks.C.Datagram networks use destination addresses and virtual-circuit networks use VC.Numbers to forward packets toward their destination.D.Datagram networks u

35、se VC.Numbers and virtual-circuit networks use destination addresses to forward packets toward their destination.76The Internets network layer is responsible for moving network-layer packets known as _ from one host to another.（）A.frame B.datagram C.segment D.message 77The protocols of various layer

36、s are called _.（）A.the protocol stack B.TCP/IP C.ISP D.network protocol 78The two important network-layer functions are _.（）A.multiplexing and de-multiplexing B.routing and forwarding C.lookup and forwarding D.routing and IP addressing 79The virtual circuit includes three identifiable phases but _.（

37、）A.setup B.data transfer C.forwarding VC numbers D.teardown 80There are some ways to accomplish the switching in the router,which one is not included?（）A.switching via memory 名师资料总结-精品资料欢迎下载-名师精心整理-第 10 页，共 14 页 -B.switching via a bus C.switching via hub D.switching via an interconnection 81In the r

38、outer,the packet queues can form at _.（）A.institutional cache B.switch fabric C.input port D.routing processor 82In IPV4 datagram header,which field is to ensure that datagram do not circulate forever in the network?（）A.type of service B.time-to-live C.header checksum D.version 83Suppose one IP data

39、gram 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.185,0 B.185,1 C.370,1 D.370,0 84Given the IP address 202.96.104.8/20,its subnet address is _.（）A.202.96.104.0 B.202.96.96.0 C.202.96.

40、104.255 D.202.96.111.255 85If the subnet mask is 255.255.240.0,then how many bits indicate the host address?（）A.20 B.24 C.12 D.16 86In the following four fields,which is in IPV6 header but not in IPV4?（）A.source address B.destination address C.version D.flow label 87One host is attached directly to

41、one router,the router is _.（）A.NAT router B.gateway router C.first-hop router D.interval router 88The Internets network layer includes the following components but _.（）A.IP protocol 名师资料总结-精品资料欢迎下载-名师精心整理-第 11 页，共 14 页 -B.the Internet Message Control Protocol C.Routing Protocol D.Channel Partitionin

42、g Protocol 89In the following protocols,which one is inter-AS routing protocol?（）A.RIP B.OSPF C.BGP D.ICMP 90In the following four descriptions about autonomous system,which one is not correct?（）A.An autonomous system is a collection of routers under the same administrative and technical control.B.A

43、ll routers in an autonomous system run the same routing protocol.C.The routing algorithm running within an autonomous system is called an intra-AS routing protocol.D.The routers that connect AS-s to each other are called default router.91 In the loop of the Dijkstras algorithm,for node x,add y to N,

44、and update the cost of y s neighbor v,then D(v)is _.（）A.c(x,v)B.minD(v),D(x)+c(x,v)C.minD(v),D(y)+c(y,v)D.c(y,v)92Consider the data D is 01110010001,if use even parity checking approach,the parity bit is(),if use odd parity checking approach,the parity bit is _.（）A.0,0 B.0,1 C.1,0 D.1,1 93The abilit

45、y to determine the interfaces to which a frame should be directed,and then directing the frame to those interfaces is _.（）A.filtering B.forwarding C.self-learning D.optimal routing 94Given that costs are assigned to various edge in the graph abstraction.In the following four descriptions,which one i

46、s not correct?（）A.The shortest path is the path with smallest number of links between the source and destination.B.The least cost path is not always the shortest path.C.If all edges have same cost,the least cost path must be the shortest path.D.If all edges have various costs,the least cost path mus

47、t not be the shortest path.95Given the IP address 202.96.104.8/20,its broadcast address is _.（）A.202.96.104.0 名师资料总结-精品资料欢迎下载-名师精心整理-第 12 页，共 14 页 -B.202.96.96.0 C.202.96.104.255 D.202.96.111.255 96If the subnet mask is 255.240.0.0,then how many bits indicate the host address?（）A.20 B.12 C.24 D.16 9

48、7In IPV6 datagram header,the field Next-header is equivalent to the field()in IPV4.（）A.upper-layer protocol B.time-to-live C.header checksum D.version 98For one host,its source router is also called _.（）A.NAT router B.gateway router C.first-hop router D.interval router 99In the following four descri

49、ptions about link-state(LS)algorithm,which one is not correct?（）A.The LS algorithm must be aware of the cost of each link in the network.B.The LS algorithm is a decentralized algorithm C.The LS algorithm computes the least cost path between a source and destination using complete global knowledge ab

50、out the network D.The calculation of LS algorithm can be run at one site or multiple sites 100In the initialization of the Dijkstras algorithm,for node x,if y is not a neighbor of x,then D(y)is _.（）A.0 B.1 C.D.c(x,y)101 In DV algorithm,when one node updates its distance vector,it must _.（）A.send the