一、选择题1．IP belongs to ( ) layer?A.transportworkC.data linkD. physical 2．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 above3．How many bits specify the IP protocol version in a datagram? ( ).A.1 bitB.2 bitsC.4 bitsD.8 bits4．In the following applications, which one is a loss-tolerant application?A E-mailB file transferC instant messagingD real-time audio5．The internet’s network layer provides a single service----that is ( ).A. Reliable data transferB. Flow controlC. Congestion controlD.Best-effort-service6．The Internet mail system has three components which they are ( ).er agent, SMTP, POP3B.SMTP, POP3, IMAPer agent, SMTP, IMAPer agent, SMTP, mail server 7．DNS means ( ).A.Data Name SystemB.Data National SystemC.Domain Name SystemD.Domain National System 8．“233.1.1.0/24”, where the /24 notation, sometimes known as a ( ).A. Subnet maskB. Networking addressC. Host addressD. None of above9．Port number’s scope is ( ) to ( ).A. 0, 1023B. 0, 65535C. 0, 127D. 0,25510．“233.1.1.0/24”, where the /24 notation, sometimes known as a( ).A. Subnet maskB. Networking addressC. Host addressD. None of above11．Which of the following is not intra-AS routing protocol? ( )A. RIPB. OSPFC. IGRPD.BGP 12．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 Data-grams are rarely larger than ( ).A. 1500 bytesB. 65535 bytesC.500 bytesD.1024 bytes 14．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．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 number17．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. RST18．ICMP is used for ( ).A. Reliable data transferB. Error reportingC. Flow controlD.Congestion control19．In the following applications, which one is a loss-tolerant application?A E-mailB file transferC instant messagingD real-time audio20．There are two fundamental approaches to building a network core, ( ) and packet switching.A. electrical current switchingB. circuit switchingC. data switchingD. message switching1．The units of data exchanged by a link-layer protocol are called ( ).A. FramesB. SegmentsC. DatagramsD. bit streams 2．In Address：,（） indicates “host name”.A. wwwB. uzzC. eduD. cn3. In the following options, which belongs to the network core? ( )A. end systemsB. routersC. clientsD. servers 4．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 Internet’s connection-oriented service has a name, it is ( ).A.TCPB. UDPC.TCP/IPD.IP6．A ( ) protocol is used to move a datagram over an individual link.A. application-layerB. transport-layerC. network-layerD. link-layer7．The FIN segment is used for ( ).A. TCP connection setupB. TCP flow controlC. TCP congestion controlD. Closing a TCP connection8．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.①④③②II. True or False.1．In CSMA/CD, one node listens to the channel before transmitting.2．In C/S architecture, client has a fixed well-known address.3．DNS resolves hostnames for hosts anywhere in the Internet.4．ARP resolves an IP address to a MAC address.5．In full-duplex transmission, the nodes at both ends of a link may transmit packets at the same time.6．IP address “136.245.255.255” can be source IP address of a packet.7．In C/S architecture, client has a fixed well-known address.8．DNS resolves hostnames for hosts anywhere in the Internet.9．ARP resolves an IP address to a MAC address.10．In full-duplex transmission, the nodes at both ends of a link may transmit packets at the same time.7. Datagram networks are circuit-switched networks, and virtual-circuit networks are packet-switched networks.8．The routing algorithm running within an autonomous system is called an intra-AS routing protocol.9．125.35.36.37 is a C-class IP address.10．In the broadcast packet of DHCP DISCOVER，source IP address is0.0.0.0. 6．In CSMA/CD, one node listens to the channel before transmitting. III. Fill in the blanks.1. _________ layer provides host-to-host services, and _______ layer provides process-to-process services.2．The port number used by HTTP is ____；The port number used by SMTP is ____；The port number used by DNS is ____.3、A hub is a _____-layer device, and switches are _____-layer devices.4．The data transmission delay includes: transmission delay、______________、processing delay and queuing delay.5．Common Channel multiplexing technology includes ___________、___________、_________、______________.6. TCP provides a _______service to its applications to eliminate the possibility of the sender overwhelming the receiver.IV. Answer.1．比较TCP和UDP之间的异同。