A router receives a packet from a neighbor with an MPLS shim header value of 0.What does the router do with this packet?（）A、It performs a label pop operation and an IP lookup.B、It performs a label swap operation and an IP lookup.C、It sends an error message toward the egress router.D、It sends an error message toward the ingress router.
A router receives a packet from a neighbor with an MPLS shim header value of 0.What does the router do with this packet?（）
- A、It performs a label pop operation and an IP lookup.
- B、It performs a label swap operation and an IP lookup.
- C、It sends an error message toward the egress router.
- D、It sends an error message toward the ingress router.
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阅读下面的短文，回答问题 [When an IP packet arrives at a router, generally the router looks at the destination address of the packet, and forwards the packet to one of its network interfaces. The forwarding decision is usually done by looking up the destination address from another data structure called a forwarding table. The forwarding table is created by the router using the routing table and possible routing policies existing in the router. The router then creates a table where it lists which networks are accessible through which of the routers network interfaces. An IP router looks at every IP packet individually and does the forwarding decision on a packet-by-packet basis. If something changes in the routers routing table, a packet can take a different route from a preceding packet even if it has the same destination.] From the paragraph above，we can see that the router （ ） a forwarding table according to the routing table and possible routing policies existing in the router. When an IP packet arrives at a router, the （ ） part of packet is normally checked by the router. An IP router checks every IP Packet individually and makes the forwarding decision based on （ ）.A．is generating B．generate C．is generated D．generates A．forwarding table B．network interfaces C．routing policies D．destination address A．the destination address and network interfaces B．forwarding table and network interfaces C．the destination address and forward table D．routing policies and routing table
● An internet is a combination of networks connected by （71） . When a datagram goes from a source to a （72） , it will probably pass many （73） until it reaches the router attached to the destination network. A router receives a （74） from a network and passes it to another network. A router is usually attached to several networks. When it receives a packet, to which network should it pass the packet? The decision is based on optimization: Which of the available （75） is the optimum pathway?（71）A. modemsB. routersC. switchesD. computers（72）A. userB. hostC. cityD. destination（73）A. destinationsB. routersC. packetsD. computers（74）A. destinationB. resourceC. packetD. source（75）A. pathwaysB. routersC. diagramsD. calls
An internet is a combination of networks connected by (71) .When a datagram goes from a source to a (72) ，it will probably pass many (73) until it reaches the router attached to the destination network．A router receives a (74) from a network and passes it to another network．A router is usually attached to several networks．When it receives a packet，to which network should it pass the packet? The decision is based on optimization： Which of the available (75) is the optimum pathway?A．modemsB．routersC．switchesD．computers
A router receives a packet from a neighbor with an MPLS shim header value of 0.What does the router do with this packet?() A. It performs a label pop operation and an IP lookup.B. It performs a label swap operation and an IP lookup.C. It sends an error message toward the egress router.D. It sends an error message toward the ingress router.
When does the E－series router start monitoring DHCP traffic using the DHCP External function?() A. When the discovery packet enters the router from the DHCP client.B. Only when the offer packet enters the router from the DHCP server.C. When the acknowledge packet enters the router from the DHCP server.D. Only when the discovery packet leaves the router going to the DHCP server.
Refer to the exhibit. What will Router1 do when it receives the data frame shown?() A.Router1 will strip off the source MAC address and replace it with the MAC address 0000.0c36.6965.B.Router1 will strip off the source IP address and replace it with the IP address 192.168.40.1.C.Router1 will strip off the destination MAC address and replace it with the MAC address 0000.0c07.4320.D. Router1 will strip off the destination IP address and replace it with the IP address of 192.168.40.1.E.Router1 will forward the data packet out interface FastEthernet0/1.F.Router1 will forward the data packet out interface FastEthernet0/2.
Refer to the exhibit. What does the (*) represent in the output?() A.Packet is destined for a local interface to the router.B.Packet was translated, but no response was received from the distant device.C.Packet was not translated, because no additional ports are available.D.Packet was translated and fast switched to the destination.
Anytime a host or a router has an IP datagram to send to another host or router, it has the（ ）address of the receiver. This address is obtained from the DNS if the sender is the host or it is found in a routing table if the sender is a router. But the IP data gram must be（ ） in a frame to be able to pass through the physical network. This means that the sender needs the （ ）address of the receiver. The host or the router sends an ARP query packet. The packet includes the physical and IP addresses of the sender and the IP address of the receiver. Because the sender does not know the physical address of the receiver, the query is（ ） over the network.Every host or router on the network receives and processes the ARP query packet, but only the intended recipient recognizes its IP address and sends back an ARP response packet.The response packet contains the recipient's IP and physical addresses. The packet is（请作答此空） directly to the inquirer by using the physical address received in the query packet. A. multicastB. unicastC. broadcastD. multiple unicast
What is the best description of serialization delay？ （）A、the time it takes for a Layer 3 switch or a router to switch a packet from an inbound interface to the queue of the outbound interfaceB、the time it takes for a propagate from source to destinationC、the time it takes to place a frame on the physical medium for transportD、the time a packet resides in the outbound queue of a router
Which of the following statements about authentication responses and conditions is true? （）(Choosetwo.)A、When a router receives a failure response, it stops querying authentication methods.B、When a router receives an error response, it stops querying authentication methods.C、If the router receives a failure response from an authentication method, it queries the next method.D、The router does not differentiate between failure and error responses; the authentication process is always interrupted.E、If it receives no response from the authentication method, a router will determine the error condition On its own; the router also has the option to proceed to the next method in a list if configured accordingly.
Which four statements about the Carrier Supporting Carrier （CSC） feature are true？ （）A、MPLS is required between the PE and CE routers that connect the backbone carrier to the customer carrier.B、The backbone carrier must enable the PE router to check that the packets it receives from the CErouter contain only the labels that the PE router advertised to the CE router.C、Every packet that crosses the backbone carrier must be encapsulated so that the packet includes MPLS labelsD、AII PE routers that link the backbone carrier to the customer carrier must run Route Target Rewrite.E、Arouting protocol is required between the PE and CE routers that connect the backbone carrierto thecustomer carrier. The routing protocol enables the customer carrier to exchange IGP routing information with the backbone carrier.
What best describes processing delay？（）A、the time required from receipt of the incoming frame， until the frame/packet has been queued for transmissionB、the time taken for a single packet to traverse the physical medium from one end to the otherC、the time taken to place a frame on the physical medium for transportD、the time spent for a packet to reside in the output queue of a router
The router receives a login request from a PPP over ATM client and examines the domain map for the client's domain. The router finds no entries currently configured within the domain map. What does the router do with the login request?（）A、The router rejects it.B、The router tunnels it via L2TP.C、The router authenticates it locally.D、The default virtual router authenticates it.
Which two statements are true about TCP communication?（）A、The receiver acknowledges the final packet in each communications stream.B、The receiver adds sequencing numbers to the packets received.C、The sender adds sequencing numbers to the packets it sends.D、The receiver acknowledges each packet it receives from the sending device.
Which message type is constructed and sent from an MSDP router to its MSDP peers when it receives a PIM register message （knowing that the MSDP router is also configured as an RP for the PIM domain）？（）A、Source-Active MessageB、PIM JoinC、PIM HelloD、MSDP Register
Which of the following statements about authentication responses and conditions is true?（）(Choose two.)A、When a router receives a failure response, it stops querying authentication methods.B、When a router receives an error response, it stops querying authentication methods.C、If the router receives a failure response from an authentication method, it queries the next method.D、The router does not differentiate between failure and error responses; the authentication process is always interrupted.E、If it receives no response from the authentication method, a router will determine the error condition on its own; the router also has the option to proceed to the next method in a list if configured accordingly.
A router receives a packet on interface 172.16.45.66/26. The source IP of the packet is 172.16.45.127/26 and the destination is 172.16.46.191/26.How will the router handle the packet?（）A、The destination is a host on another subnet, so the router will not forward the packet.B、The destination is a host on the same subnet, so the router will forward the packet.C、The destination is a broadcast address, so the router will not forward the packet.D、The destination is a network address, so the router will forward the packet.
单选题A router receives a packet on interface 172.16.45.66/26. The source IP of the packet is 172.16.45.127/26 and the destination is 172.16.46.191/26.How will the router handle the packet?（）AThe destination is a host on another subnet, so the router will not forward the packet.BThe destination is a host on the same subnet, so the router will forward the packet.CThe destination is a broadcast address, so the router will not forward the packet.DThe destination is a network address, so the router will forward the packet.
单选题A router receives an IPv6 packet which is 2000 bytes in length. The MTU of the outgoing interface is 1500 bytes. What action will the router take？（）Aforwards the packetBfragments the packetCdrops the packet silentlyDdrops the packet and sends an ICMP message
单选题An internet is a combination of networks connected by (1). When a datagram goes from a source to a (2), it will probably pass many (3) until it reaches the router attached to the destination network. A router receives a (4) from a network and passes it to another network. A router is usually attached to several networks. When it receives a packet, to which network should it pass the packet? The decision is based on optimization: Which of the available (5) is the optimum pathway?空白（4）处应选择（）AdestinationBresourceCpacketDsource
单选题When does the E-series router start monitoring DHCP traffic using the DHCP External function?（）AWhen the discovery packet enters the router from the DHCP client.BOnly when the offer packet enters the router from the DHCP server.CWhen the acknowledge packet enters the router from the DHCP server.DOnly when the discovery packet leaves the router going to the DHCP server.
单选题What is the best description of serialization delay？ （）Athe time it takes for a Layer 3 switch or a router to switch a packet from an inbound interface to the queue of the outbound interfaceBthe time it takes for a propagate from source to destinationCthe time it takes to place a frame on the physical medium for transportDthe time a packet resides in the outbound queue of a router
单选题What best describes processing delay？（）Athe time required from receipt of the incoming frame， until the frame/packet has been queued for transmissionBthe time taken for a single packet to traverse the physical medium from one end to the otherCthe time taken to place a frame on the physical medium for transportDthe time spent for a packet to reside in the output queue of a router
单选题A router receives an IPv6 packet which is 2000 bytes in length. The MTU of the outgoing interface is 1500 bytes. Which action will the router take?（）AForward the packet.BFragment the packet.CDrop the packet silently.DDrop the packet and send an ICMPv6 message.
单选题A router receives a packet from a neighbor with an MPLS shim header value of 0.What does the router do with this packet?（）AIt performs a label pop operation and an IP lookup.BIt performs a label swap operation and an IP lookup.CIt sends an error message toward the egress router.DIt sends an error message toward the ingress router.