计算机网络虚数
是非题
1.In computer networking jargon, the computers connected to the Internet are referred to as end systems, including rvers , routers, mobile computers.
2.One of the attractive features of DSL and HFC is that the rvices are always on。
3.HTTP/1.1 us inpersistent HTTP with pipelining.
4.UDP socket is identified by two-tuple: dest IP address, dest port number.
5.The IPv6 address space is 264.
6.ARP translates computer name to network-layer address.
7.HTTP us reliably transfer email message from client to rver, port number is 52.
8.Link Layer Services include Error Detection, full-duplex etc.
9.Star topology popular through mid 90s, Now bus topology prevails.
10.FTP,SMTP,POP3 and IMAP run on top of TCP rather than UDP.
11.With the SR protocol ,it is possible for the nder to receive an ACK for a packet that falls outside of its current window.
12.With GBN, it is possible for the nder to receive an ACK for a packet that falls outside of its current window.
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13.Ethernet frames can carry more than 1500 bytes of data ,whereas frames for some wide-area links can carry no mare than 576 bytes.
14.Ipv6 allows for fragmentation at routers and IP header to be extended,but Ipv4 not.
15.For TDM, the time domain is gmented into four circuits; each circuit is assigned the same dedicated slot in the revolving TDM frames. The transmission rate of the frame is equal to the frame rate multiplied by the number of bits in a slot.
16.Most packet switches u store and forward transmission at the inputs to the links. Store-and-forward transmission 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.
17.If a network employs virtual circuits, then the network's switches must maintain the ongoing connections. Specifically, each time a new connection is established connection entry must be added to the switch's VC number translation table; and each time a connection is relead, an entry must be removed from the table.
名词解释：写英文全称和汉语全称
DNS Domain Name System 域名系统
FDM Frequency Division Multiplexing 频分多路复用
SMTP Simple Mail Transfer Protocol 简单邮件传输协议
课程英语TCP Transport Control Protocol 传输控制协议
RIP Routing Information Protocol 路由信息协议
ARP Address Resolution Protocol 地址解析协议
CSMA/CD Carrier Sen multiple Access/ Collision Detection 带有碰撞检测的载波侦听多点访问
MIME Multipurpo Internet Mail Extensions 多用途英特网邮件扩充协议
填空题
1.DNScvoked by an application to obtain the canonical hostname for a supplied alias hostname as well as the（IP address）of the host。alex wong
2.Two approaches toward congestion control are （end-to-end congestion control）and （network assisted congestion control）
3.The most fundamental responsibility of UDP and TCP is to extend IP's delivery rvice, extending host-to-host delivery to process-to-process delivery is called （transport layer multiplexing 多路传输、复用）and（demultiplexing多路分解）
4.Four types of OSPF routers（internal routers ）（boundary routers）（areas border routers）（backbone routers）
5.（filtering）(过滤、筛选)is the ability to determine whether a frame should be forwarded to an interface or should just be dropped.When the frame should be forwarded, （forwarding）（转发、运输）is the ability to determine which of the interfaces the frame should be directed to. The are don
e with a （switch table）.
6.Two generic forms of pipelined（流水线）protocols are （Go-back-N）and (lective repeat ).
7.(flow control)means that nder won’t overflow receiver’s buffer by transmi tting too much, too fast. ( congestion control)is ud to prevent too many hosts from nding too much data too fast for network to handle.
8.Moving packets from router’s input to appropriate router output is called (forwarding). Determining route taken by packets from source to dest is called ( routing).
( RIP) and (OSPF ) are two routing protocols have been ud for routing within an autonomous system in the internet.建筑工程发票
9.In practice, algorithms with global state information are referred to as (link state)algorithm,since the algorithm must be aware of the cost of each link in the network. The decentralized routing algorithm is called (distance vertor ) algorithm,becau each node maintain a vector of estimates of the costs to all other nodes in the network.
10.Each IP node (Host, Router) on LAN has ARP table, ARP Table includes three parts: ( IP address)
,( MAC address)and TTL.
11.Any multiple access protocol belongs to one of the three categories: (channel partitioning protocol),(Random Access )and taking-turns protocols.
12.A switch has the property of building its table automatically, dynamically and autonomously -- without anyintervention from a network administrator or from a configuration protocol. In other words, switches are （lf-learning / plug and play）。
13.Data which an application wants to nd and pasd onto the transport layer are called （application-layer message ）。Data generated by the transport layer and encapsulates application-layer message with transport layer header are called（transport-layer gments）。Data encapsulated transport-layer gment with a network-layer header are called（datagram）。Data ncapsulated network-layer datagram with a link-layer header are called（frame）。
14.Three predominent architectures ud in modern network applications are （client/rver），（peer-to-peer），（Hybrid of client/rver and peer-to peer）。
worry15.There are two fundamental approaches to build a network core: (circuit switching)and ( packet switching).
16.Access networks can be classified into three categories: ( residential access network),( institutional access network), mobile access networks.
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17.Internet standards are developed by ( Internet Telecommunication Union), the Internet documents are called ( FTP files).
18.What rvices might a network application need from a transport protocol? We can broadly classify an application's rvice requirements along three dimensions: (data loss), (band width), and timing.
19.The TCP rvice model includes a ( connect-oriented rvice) and a (realiab data transfer rvice). When an application invokes TCP for its transport protocol, the application receives both of the rvices from TCP.
爱国演讲20.FTP us two parallel TCP connections to transfer a file, （control connection）is ud for nding control information between the two hosts, such as ur identification, password, commands to change remote directory, and commands to "put" and "get" files.（data connection）is ud to actually nd a file.
21.At the receiving end, the transport layer can then examine this field to determine the receiving process, and then direct the gment to that process. This job of delivering the data in a transport-layer gment to the correct application process is called（demultiplexing）. The job of gathering data at the source host from different application process, enveloping the data with header information to create gments, and passing the gments to the network layer is called （multiplexing）.
22.There are two types of network links , a ( point-to-point) link consists of a single nder at one end of the link and a single receiver at the other end of the link. A (broadcast)link can have multiple nding and receiving nodes all connected to the same, single,shared channel.
选择题
1.（C）is reliable data transfer over channels with errors and loss。
A) rdt1.0 B)rdt2.0
C) rdt3.0 D)rdt2.1
2.In the following four types of delays ,( C) is uncertain 。
A)processing delay B) transmission delay
C) queuing delay D) propogation delay
3.Application that us either TCP or UDP is ( A)。
A) Streaming multimedia B) Electronic mail
C)File transfer D)Web
4.( C) is called sliding-window protocol.。
A)SR protocol B)ARQ protocol
C)Go-Back-N protocol D)Alternating-bit protocol
5.During the period of encapsulation at the nding host，the network layer takes data
from transport-layer and appends network-layer header information，creating a network-layer （C）。
英语教育专业A) message B)gment
C) datagram D)frame
6.The time required to examine the packet’s header and determine where to direct the packet is the part of the ( A)。
A）nodal processing B）queuing
C) transmission D) propagation
7.Which application runs over TCP rather than UDP? ( A)
A) file transfer B)streaming multimedia
C) DNS D)internet telephony
8.（ A ）are responsible for com, org, net, edu, etc.
A) Top-level domain (TLD) rvers B) Authoritative DNS rvers
C) Local Name Server D）Root name rvers
9.The Internet's address assignment strategy is known as ( B )。
A)longest prefix matching rule B)CIDR(Classless Interdomain Routing)
C)classful addressing D)address aggregation日语量词
10.( D ) translates network-layer address to link-layer address。
A) DNS B) IGMP
C)MPLS D) ARP
简答：
1.What are some characteristics of TCP?
Full-duplex data Connection-oriented Flow control congestion control point-to-point Piplined nd&receive buffer Reliable in-order byte stream
2.Why is it said that FTP nds control information "out of band"?
FTP u two parallel TCP connection:one connection for nding control connection and another Connection for actually transferring file.
Becau the control information is not nt over the same connection that the file is nd over . FTP nds control information out of band;
3.Compare and contrast Link state algorithms and Distance-vector routing
