网络工程师-计算机专业英语(五)
(总分100,考试时间90分钟)
单项选择题
Traditional IP packet forwarding analyzes the ______ IP address contained in the network layer header of each packet as the packet travels from its source to its final destination. A router analyzes the destination IP address independently at each hop in the network. Dynamic ______ protocols or static configuration builds the databa needed to analyze the destination IP address (the routing table). The process of implementing traditional IP routing also is called hop-by-hop destination-bad ______ routing. Although successful, and obviously widely deployed, certain restrictions, which have been realized for some time, exist for this method of packet forwarding that diminish its ______. New techniques are therefore required to address and expand the functionality of an IP-bad network infrastructure. This first chapter concentrate on identifying the restrictions and prents a new architecture, known as multipleprotocol ______ switching, that provides solutions to so
me of the restrictions.
1. A. datagram B. destination C. connection D. rvice
2. A. routing B. forwarding C. transmission D. management
3. A. anycast B. multicast C. broadcast D. unicast
4. A. reliability B. flexibility C. stability D. capability
脚踝受伤5. A. const B. cast C. mark D. label
The de facto standard application program interface ______ for TCP/IP applications is the "sockets" interface. Although this API was developed for ______ in the early 1980s. it has also been implemented on a wide variety of non-Unix systems. TCP/IP ______ written using the sockets API have in the past enjoyed a high degree of portability and we would like the same ______ with IPv6 applications. But changes are required to the sockets API to support IPv6 and this memo describes the changes. The include a new socket address structure to carry IPv6 ______, new address conversion functions, and some new socket options. The extensions are designed to provide Access to the basic IPv6 features required by TCP and UDP applications, including multicasting, while introducing a minimum of change into the system and **plete ______ for existing IPv4 applications.
战斗部
6. A. Windows B. Linux C. Unix D. DoS
爱国爱教7. A. applications B. networks C. protocols D. systems
8. A. portability B. availability C. capability D. reliability
9. A. connections B. protocols C. networks D. address
10. A. availability B. compatibility C. capability D. reliability
The TCP protocolis a ______ layer protocol. Each connection connects two TCPs that may be just one physical network apart or located on opposite sides of the globe. In other words, each connection creates a ______ witha length that may be totally different from another path created by another connection. This means that TCP cannot u the same retransmission time for all connections. Selecting a fixed retransnussion time for all conn
ections can result in rious conquences. If the retransmission time does not allow enough time for a ______ to reach the destination and an acknowledgment to reach the source, it can result in retransmission of gments that are still on the way. Converly, if the retransmission time is longer than necessary for a short path, it may result in delay for the application programs. Even for one single connection, the retransmission time should not be fixed. A connection may be able to nd gments and receive ______ faster during nontraffic period than during congested periods. TCP us the dynamic retransmission time, a transmission time is different for each connection and which may be changed during the same connection. Retransmission time can be made ______ by basing it on the round-trip time (RTT). Several formulas are ud for this purpo.
11. A.physical Bwork C.transport D.application
12. A.path B.window C.respon D.process
13. A.process B.gment C.program D.ur
14. A.connections B.requests C.acknowledgments D.datagrams
不堪重负
查理曼
15. A.long B.short C.fixed D.dynamic鸡的成语大全四个字
阅读手抄报简单又漂亮Let us now e how randomization is done when a collision occurs. After a ______, time is divided into discrete slots who length is equal to the worst-ca round-trip propagation time on the ether (2t). To accommodate the longest path allowed by Ethernet, the slot tome has been t t0 512 bit times, or 51.2μc.
After the first collision, each station waits either 0 or 1 ______ times before trying again. If two stations collide and each one picks the same random number, they will collid
e again. After the cond collision, each one picks either 0, 1, 2, or3 at random and waits that number of slot times. If a third collision occurs (the probability of this happening is 0.25), then the next time the number of slots to wait is chon at ______ from the interval 0 to 23-1.
In general, after i collisions, a random number between 0 and 2i-1 is chon, and that number of slots is skipped. However, after ten collisions have been reached, the randomization ______ is frozen at a maximum of 1023 slots. After 16 collisions, the controller throws in the towel and reports failure back to **puter. Further recovery is up to ______ layers.
16. A.datagram B.collision C.connection D.rvice
17. A.slot B.switch C.process D.fire
18. A.rest B.random C.once D.odds
19. A.unicast B.multicast C.broadcast D.interval
20. A.local B.next C.higher D.lower
惩罚游戏
Border Gateway Protocol(BGP) is inter-autonomous system ______ protocol. BGP is bad on a routing method called path vector routing. Distance vector routing is not a good candidate for inter-autonomous system routing becau there are occasions on which the route with the smallest ______ count is not the preferred route. For example, we may not want a packet through an autonomous system that is not cure even though it is shortest route. Also, distance vector routing is unstable due to the fact that the router
s announce only the number of hop counts to the destination without defining the path that leads to that ______. A router that receives a distance vector advertiment packet may be fooled if the shortest path is actually calculated through the receiving router itlf. Link ______. routing is also not a good candidate for inner-autonomous system routing becau an internet is usually too big for this routing method. To u link state routing for the whole internet would require each router to have a huge link state databa. It would also take a long time for each router to calculate its routing ______ using the Dijkstra algorism.
