●Transport gateways connect byte streams in the transport layer．Application gateways allow interworking above (72) ．(72) A．network layerB．data link layerC．transport layerD．appfication layer
●Transport gateways connect byte streams in the transport layer．Application gateways allow interworking above (72) ．
(72) A．network layer
B．data link layer
C．transport layer
D．appfication layer
相关考题：
LANs can be connected by using bridges, which operate in theA．physical layerB．data link layerC．network layerD．transport layer
●The Simple Network Management Protocol (SNMP)is an (71) protocol that facilitates the exchange of management information between (72) ．It is part of the Transmission Control Protocol/Internet Protocol(TCP/IP) protocol suite．SNMP enables network (73) to manage network performance, find and sole network problems,and plan for (74) ．An SNMP-managed network consists of three key components:managed devices , (75) ,and network-management systems ．(71) A．Physical LayerB．Link LayerC．Network LayerD．Transport Layer(72) A．network stationsB．network clientsC．network devicesD．network servers(73) A．serversB．administratorsC．computersD．routers(74) A．network growthB．network structureC．network architectureD．network servers(75) A．administratorsB．agentsC．managersD．servers
● A transport layer protocol has several responsibilities. One is to create a process-to-process (program-to-program) communication; TCP uses port （71） to accomplish this. Another responsibility of a transport layer protocol is to create a （72） and error-control mechanism at the transport level. TCP uses a sliding （73） protocol to achieve flow control. It uses the acknowledgment packet, time-out, and retransmission to achieve （74） control. The transport layer is also responsible for providing a connection mechanism for the application program. The application program sends （75） of data to the transport layer. It is the responsibility of the transport layer at the sending station to make a connection with the receiver.（71）A. numbersB. connectionsC. diagramsD. resources（72）A. procedureB. functionC. routeD. flow（73）A. pathB. windowC. frameD. diagram（74）A. packetB. timeC. errorD. phase（75）A. portsB. streamsC. packetsD. cells
● A glue that holds the whole Internet together is the network layer protocol,(71). Unlike most older network layer protocols, it was designed from the beginning with internetworking in mind. Its job is to provide a -(72) way to transport datagrams from source to destination, without regard to whether these machines are on the same network or whether there are other networks in between them.Communication in the Internet works as follows. The (73)layer takes data streams and breaks them up into datagrams. Each datagram is transmitted through the Internet, possibly being fragmented into smaller units as it goes. When all the pieces finally get to the destination machine, they are reassembled by the(74) layer into the original datagram. This datagram is then handed to the transport layer, which inserts it into the receiving process' input stream.An IP datagram consists of a header part and a text part. The header has a (75) part and a variable length optional part.(71) A. IP (Internet Protocol)B. IP (Interworking Protocol)C. TCP (Transport Control Protocol)D. TCP (Transfer Communication Protocol)(72) A. best-qualityB. quality-guaranteedC. connection-orientedD. best-efforts(73) A. data linkB. transportC. networkD. application(74) A. data linkB. transportC. networkD. application(75) A. 40-byte fixedB. 64-byte fixedC. 20~64 bytes variableD. 20-byte fixed
Transport gateways connect byte streams in the transport layer. Application gateways allow interworking aboveA．network layerB．data link layerC．transport layerD．application layer
Networks can be interconnected by different devices in the physical layer networks can be connected by (71) or hubs．which just move the bits from one network to an identical network．One layer up we find bridges and switches which operate at data link layer．They can accept (72) ，examine the MAC address and forward the frames to a different network while doing minor protocol translation in the process in me network layer，we have routers that can connect two networks，If two networks have (73) network layer，the router may be able to translate betweenthe packer formats．In the transport layer we find transport gateway，which can interface between two transport connections Finally，in the application layer，application gateways translate message (74) ．As an example，gateways between Internet e-mail and X，400 e-mail must (75) thee-mail message and change various header fields．(68)A．reapersB．relaysC．packagesD．modems
is the 4th layer of the OSI reference model responsible for reliable network communication between end nodes.A．Data link layerB．Session layerC．Transport layerD．Application layer
Each machine supporting TCP has a TCP transport entity, either a library procedure, a user process, or part of the kernel. In all case, it manages TCP streams and (71) to the IP layer. A TCP (72) accepts user data streams from local process, breaks them into pieces not exceeding 64KB, and sends each piece as a separate IP (73). When datagrams containing TCP data arrive at a machine, they are given to the TCP entity, which reconstructs the original byte streams.The IP layer gives no guarantee that datagrams will be delivered properly, so it is up to TCP to time out and (74) them as need be. Datagmms do arrive may well do so in the wrong order, it is also up to TCP to (75) them into messages in the proper sequence.A．callsB．interfacesC．linksD．produces
● TCP/IP communication protocol contains four layers. From bottom to top, the four layers are __(71)__.（71）A．network interface layer, internet layer, transport layer and application layerB．internet layer, network interface layer, transport layer and application layerC．network interface layer, transport layer, network interface layer and application layerD．application layer, transport layer, internet layer and network interface layer
A transport layer protocol has several responsibilities. One is to create a process-to-process (program-to-program) communication; TCP uses port (71) to accomplish this. Another responsibility of a transport layer protocol is to create a (72) and error-control mechanism at the transport level. TCP uses a sliding (73) protocol to achieve flow control. It uses the acknowledgment packet, time-out, and retransmission to achieve (74) control. The transport layer is also responsible for providing a connection mechanism for the application program. The application program sends (75) of data to the transport layer. It is the responsibility of the transport layer at the sending station to make a connection with the receiver.（71）A．numbersB．connectionsC．diagramsD．resources
● The TCP protocol is a __（72）__ layer protocol．（72） A． physical B． network C． transport D． application
● A transport layer protocol usually has several responsibilities. One is to create a process-to-process communication; UDP uses （71） numbers to accomplish this. Another responsibility is to provide control mechanisms at the transport level. UDP does this task at a very minimal level. There is no flow control mechanism and there is no （72） for received packet. UDP,however, does provide error control to some extent. If UDP detects an error in the received packet, it will silently drop it．The transport layer also provides a connection mechanism for the processes. The （73） must be able to send streams of data to the transport layer. It is the responsibility of the transport layer at （74） station to make the connection with the receiver, chop the stream into transportable units,number them, and send them one by one. It is the responsibility of the transport layer at the receiving end to wait until all the different units belonging to the same process have arrived, check and pass those that are （75） free, and deliver them to the receiving process as a stream.（71）A．hop B．port C．route D．packet（72）A．connection B．window C．acknowledgement D．destination（73）A．jobs B．processes C．programs D．users（74）A．sending B．routing C．switching D．receiving（75）A．call B．state C．cost D．error
Which layer-function is mostly implemented in a network adapter（ ）。A.Physical layer and link layerB.Network layer and transport layerC.Physical layer and network layerD.Transport layer and application layer
LANs can be connected by using bridges, which operate in the(67).A．data-link layerB．Physical layerC．network layerD．transport layer
Together with the network layer,the transport layer is the heart of the protocol（ ）The network layer provides end-to-end（ ） delivery using datagrams or virtual circuits.The transport layer builds on the network layer to provide data transport from a process on a（ ）machine to a process on a destination machine with a desired level of reliability that is independent of the physical （ ） currently in use.It provides the abstractions that applications nedd to use the network..Without the（ ） layer,the whole concept of layered protocols would make little sense.A.transport B.network C.hierarchy D.service A.packet B.data C.command D.record A.connection B.terminal C.source D.destination A.traffic B.connection C.lines D.networks A.network B.transport C.link D.physical
At which layers of the OSI model do WANs operate?() A.application layerB.session layerC.transport layerD.network layerE.datalink layerF.physical layer
At which layers of the OSI model do WANs operate (Choose two.)()。 A.application layerB.session layerC.transport layerD.network layerE.datalink layerF.physical layer
● Networks can be interconnected by different devices. In the physical layer，networks can be connected by（1）or hubs，which just move the bits from one network to an identical network. One layer up we find bridges and switches，which operate at data link layer. They can accept（2）,examine the MAC address，and forward the frames to a different network while doing minor protocol translation in the process. In the network layer，we have routers that can connect two networks. If two networks have（3）network layer， the router may be able to translate between the packet formats. In the transport layer we find transport gateway， which can interface between two transport connections. Finally，in the application layer， application gateways translate message（4）.As an example， gateways between Internet e-mail and X.400 e-mail must （5）the e-mail message and change various header fields.（1）A.reapersB.relaysC.connectorsD.modems（2）A.framesB.packetsC.packagesD.cells（3）A.specia lB.dependentC.similarD.dissimilar（4）A.syntaxB.semanticsC.languageD.format（5）A.analyzeB.parseC.deleteD.create
根据下面的文字资料回答 71～75 题 connected by（ 1 ）or Hubs,which just move the bits from one network to an identical network. One layer up we find bridgas and swiehes,which operate at data link layer. They can accept （ 2 ） , examine the MAC address, and forward the frames to a different network while doing minor protocol translation in the process. In the network layer,we have touters that can connect two netwoks. If two networks have（ 3 ）network layer,the router may be able to translate between the packet formats. In the transport layer we find transport gateway, which cart interface between the two transport connections. Finally, in the application layer, application gateways translate message（ 4 ）. As an example,gateways between Internet e-mail and X.400 e-mail must （ 5 ）the e-mail message and change various header fields.第6题：文中（ 1 ）处正确的答案是（ ）。A．reapersB．relaysC．connectsD．modems
Which OSI layer does a bridge operate at?A．the Physical LayerB．the Network LayerC．the Transport LayerD．the Data Link Layer
● Each machine supporting TCP has a TCP transport entity, either a library procedure, a user process, or part of the kernel. In all case, it manages TCP streams and （71） to the IP layer. A TCP （72） accepts user data streams from local process, breaks them into pieces not exceeding 64KB, and sends each piece as a separate IP （73） . When datagrams containing TCP data arrive at a machine, they are given to the TCP entity, which reconstructs the original byte streams. The IP layer gives no guarantee that datagrams will be delivered properly, so it is up to TCP to time out and （74） them as need be. Datagrams do arrive may well do so in the wrong order, it is also up to TCP to （75） them into messages in the proper sequence.（71）A. callsB. interfacesC. linksD. produces（72）A. connectionB. fileC. entityD. destination（73）A. datagramB. streamC. connectionD. transaction（74）A. reassembleB. reduceC. re-createD. retransmit（75）A. reassembleB. reduceC. re-createD. retransmit
TCP/IP communication protocol contains four layers. From bottom to top, the four layers are （ ） .A.network interface layer—internet layer—transport layer—application layerB.internet layer —network interface layer—transport layer—application layerC.network interface layer—transport layer —network interface layer—application layerD.application layer—transport layer —internet layer—network interface layer
Networks can be interconnected by different devices in the physical layer networks can be connected by（ ）_or hubs.which just move the bits from one network to an identical network.One layer up we find bridges and switches which operate at data link layer.They can accept（ ）examine the MAC address and forward the frames to a different network while doing minor protocol translation in the process in me network layer,we have routers that can connect two networks,If two networks have（ ）network layer,the router may be able to translate between the packer formats.In the transport layer we find transport gateway,which can interface between two transport connections Finally,in the application layer,application gateways translate message（请作答此空）.As an example,gateways between Internet e-mail and X.400 e-mail must（ ）the e-mail message and change various header fields.A.syntaxB.semanticsC.languageD.format
Which layer-function is mostly implemented in a network adapter?（ ）.A.Physical layer and link layerB.Network layer and transport layerC.Physical layer and.network layer D.Transport layer and application layer
Both TCP and UDP belong to ( ) layer of the OSI mode。A.session B.transport C.networkD.data link
The TCP/IP stack is a complete set of networking protocols.The OSI Model was meant to be a standardized way of connecting devices together,and most protocols have some direct correlation to the OSI Model.The OSI Model has 7 layers,the fourth layer is called______.A.physical layerB.data link layerC.application layerD.transport layer
When gateways are registering with a gatekeeper， the gatekeeper can be（）.A、On the same subnetB、On a remote LANC、In a different subnetD、Any of the above