09上
The Border Gateway Protocol (BGP) is an interautonomous system （71） protocol.The primary function of a BGP speaking system is to exchange network （72） information with other BGP system. This network reachability information includes information on the list of Autonomous System (ASs) that reachability information travers. BGP-4 provides a new t of mechanisms for supporting （73） interdomain routing. The mechanisms include support for advertising an IP （74） and eliminate the concept of network class within BGP.BGP-4 also introduces mechanisms that allow aggregation of routes, including （75） of AS paths. The changes provide support for the propod supernettting scheme.
（71）A. connecting B. resolving C. routing D. supernettting
sicong （72）A. cubility B. reachability C. capability D. reliability
（73）A. answerless B. connectionless C. confirmless D. classless
（74）A. prefix B. suffix C. infix D. reflex
（donated75）A. rervation B. relation C. aggregation D. connection
参考译文
边界网关协议BGP是自治系统时间的路由协议。BGP发布系统的基本功能就是与其他BGP系统交换网络可达性信息。这种网络可到达性信息包含了可到达性信息穿越的自治系统的列表。BGP-4提供了一系列新的机制来支持无类别的域间路由。这些机制包括支持发布IP前缀，从而在BGP中排除了网络类别的概念。BGP-4也引入了路由聚合机制，包括AS通路的聚合。这些改变提供了对提议的超网方案的支持。
参考答案
（71）C （72）B （73）D （74）A （75）C
08下
The usual way to ensure reliable delivery is to provide the （71） with some feedback about what is happening at the other end of the line. Typically, the protocol calls for the receiver to nd back special （72） frame bearing positive or negative （73） about the incoming frames. If the nder receives a positive acknowledgement about a frame, it knows the frame has arrived safely. On the other hand, a negative acknowledgement means that something has gone wrong, and the frame must be transmitted again.
An additional complication comes from the possibility that hardware troubles may cau a frame to （74） completely. In this ca, the receiver will not react at all, since it has no any reason to react. It should be clear that a protocol in which the nder transmits a frame and then waits for an acknowledgement, positive or negative, will hang forever if a frame is ever lost due to, for example, （75） hardware.
（71）A. receiver B. controller C. nder D. customer
（72）A. data B. control C. request D. ssion
（73）A. application B. connection C. stream D. acknowledgement
（74）A. vanish B. vary C. appear D. incline
（75）A. acting B. working C. malfunctioning D. functioning
参考译文
保证可靠提交的常用方法是向发送端提供一些反馈信息，使它知道在线路的另一端发生了什么情况。典型的情况是：协议要求接收端回送一个承载有关输入帧的肯定或否定应答的特殊控制帧。如果发送端收到了有关帧的肯定应答，它就知道发送的帧已经安全到达。另一方面，否定应答则意味着出现了某种错误，应该重新发送出错的帧。
还有一些复杂的情况可能发生，硬件故障可能引起帧完全消失。在这种情况下，接收端完全没有反应，因为它根本无法反应。显然，如果一个帧由于硬件失效而丢失了，那么这样的协议--发送端发出一个帧然后等待肯定或否定应答，就会被永远地挂起了。
参考答案
（71）C （72）B （73）D （74）A （75）C
08上
WLANs are increasingly popular becau they enable cost-effective connections among people and applications that were not possible in the past. For example, WLAN-bad applications can enable fine-grained management of supply （71） to improve their efficiency and reduce （72）. WLANs can also enable entirely new business process. To cite but one example, hospitals are using WLAN-enabled point-of-care （73） to reduce errors and improve overall patient care. WLAN management solutions provide a variety of other benefits that can be substantial but difficult to measure. For example, they can protect corporate data by preventing rhymes（74） through rogue access points. They can i
mprove overall network management by integrating with customers’ existing systems. Fortunately, it isn’t necessary to measure the benefits to justify investing in WLAN management solutions, which can quickly pay for themlves simply by minimizing time-（75） deployment and administrative chores.
（71）A. custom B. rver C. chains D. chances
（72）A. overhead B. connection C. supply D. effect
（73）A. transportations B. applications C. connections D. translations
（74）A. integration B. interest C. instruction D. intrusion
（75）A. capable B. consuming C. effective D. connected
参考译文
无线局域网（WLAN）日益普及起来，这是因为它能在用户和应用之间有效地建立连接，这在过去是难以做到的。例如基于WLAN的应用可以对供应链进行细粒度的管理，从而改进效率，减少开销。WLAN也可以创造全新的商业过程。仅举出其中的一个例子，医院使用基于WLAN的护理点应用来减少差错，全面改进病员护理。WLAN管理解决方案提供的各种实质上的好处是很难度量的。例如，它可以保护公司的数据，防止恶意的访问。它可
以全面地改进网络管理，并集成到用户现有的系统中。幸好，我们无需量化这些收益来证明WLANnally解决方案的合理性，因为它能很快地补偿由于部署这些应用和管理事务而付出的时间开销。
参考答案
（71）C （72）A （73）B （74）D （75）B
07下
Traditional Internet access methods like dial-up were so slow that host computers were connected to the dial-up （71） at the customer premi over slow （72） ports. PPP was designed to run directly over the rial links. But with the advent of broadband Internet （73） technologies such as ADSL and cable modems there has been a considerable increa in the bandwidth delivered to the end urs. This means that the host computers at the customer premi connect to the （74） or cable "modem" over a much faster medium such as Ethernet. It also means that multiple （75） can connect to the Internet through the same connection.
（71）A. buffer B. modem C. computer D. rver
（72）A. parallel B. digital C. rial D. variable
（73）A. access B. cache C. cast D. storage
（the vow74）A. FDDI B. HDSL C. ADSL D. CDMA
（75）A. cables B. hosts C. rvers D. modems
参考译文
传统的Internet接入方法（例如拨号接入）速度很慢，这种方式要求客户端主机通过低速串口连接到拨号Modem，在串行链路上运行PPPinternational协议。但是随着宽带Internet接入技术--例如ADSL和线缆调制解调器的发展，提供给端用户的带宽已经有相当大的增加。这意味着客户端主机可以连接到ADSL或者线缆调制解调器，从而获得比以太网还要快得多的传输介质。这也意味着多个主机可以通过同一连接访问Internetmythos。
参考答案
（71）B （72）C （73）A （74）C （75）B
07上
Serialization delay and （71） delay are the two components of network delay that are improved by increasing bandwidth. Serialization delay, i.e. the amount of time it takes to put the （晚安英文72） on the wire, and queuing delay (depth of the queue) are improved by increasing the （73） from a 128Kbps circuit to a T1. However, three other components of delay, routing/switching delay, distance delay, and protocol delay are components that can not bepositively affected by an （74） in bandwidth. If the circuits are not over-utilized, thenincreasing the bandwidth to improve the （75） of the application will only result in an incread bandwidth with no positive effects on performance.
（71）A. buffering B. queuing C. receiving D. timing
（72）A. electricity B. digital C. data D. variable
（73）A. memory B. cache C. bandwidth D. delay
（74）A. increa B. decrea C. maintenance D. extension
（75）A. capability B. cost C. amount D. performance
参考译文
串行排序延迟和队列延迟是网络延迟的两个主要因素，这些是可以通过增加带宽加以改进
的。串行排序延迟（将数据输出到线路上需要的时间）和队列延迟（队列的长度）可以通过把带宽从128Kbps增加到T1得到改善。然而，另外三种延迟因素--路由/交换延迟、距离延迟和协议处理延迟是不能通过增加带宽来改进的。如果线路没有超量使用，则通过增加带宽来改进应用软件性能的企图只能产生一种结果，那就是带宽的增加对性能并没有产生正面的影响。
参考答案srv
（71）B （72）C （73）C usl（74）A （75）D
