Assuming that an IP packet is sent from a source address in VLAN1 to a destination address in VLAN2 through a layer-3 switch, which part of the packet will be changed?（）A、Layer 2 TTLB、Layer 3 TTLC、Layer 3 source addressD、Layer 3 destination address
Assuming that an IP packet is sent from a source address in VLAN1 to a destination address in VLAN2 through a layer-3 switch, which part of the packet will be changed?（）
- A、Layer 2 TTL
- B、Layer 3 TTL
- C、Layer 3 source address
- D、Layer 3 destination address
相关考题：
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
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.
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
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 database needed to analyze the destination IP address（the routing table）.The process of implementing traditional IP routing also is called hop-by-hop destination-based（ ）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 is（请作答此空）.New techniques are therefore required to address and expand the functionality of an IP-based network infrastructure.This first chapter concentrates on identifying these restrictions and presents a new archiecture，known as multiprotocol（ ）switching，that provides solutions some of these restrictions.A.reliabilityB.flexibilityC.stabilityD.capability
PTN： Packet Transport Network（分组传送网络） ，其中Packet（分组）是指具备（）、多业务（IP化业务）接入、业务带宽共享和分类QOS保障管理能力。 A、IP化分组内核B、大颗粒交换内核C、光信号交换内核
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.
Which statement correctly describes the disabling of IP TTL propagation in an MPLS network？（）A、The TTL field from the IP packet is copied into the TTL field of the MPLS label header at the ingress edge LSRB、TTL propagation cannot be disabled in an MPLS domainC、TTL propagation is only disabled on the ingress edge LSRD、The TTL field of the MPLS label header is set to 255E、The TTL field of the IP packet is set to 0
给了两段documentation里的描述，问这个时候发哪种类型的ICMP包。 The interface on which the packet comes into the router is the same interface on which the packet gets routed out. The subnet or network of the source IP address is on the same subnet or network of the next-hop IP address of the routed packet.
If the router R1 has a packet with a destination address 192.168.1.255, what describes the operation of the network（）。A、R1 will forward the packet out all interfaces.B、R1 will drop this packet because this it is not a valid IP address.C、As R1 forwards the frame containing this packet, Sw-A will add 192.168.1.255 to its MAC table.D、R1 will encapsulate the packet in a frame with a destination MAC address of FF-FF-FF-FF-FF-FFE、As R1 forwards the frame containing this packet, Sw-A will forward it to the device assigned the IP address of 192.168.1.255.
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.
Examine the following configuration on Router R1. R1's show ip route 172.16.4.1 command list s a route with outgoing interface S0/1/1. Host 172.16.3.3 uses telnet to connect to host 172.16.4.1.What will Router R1 do with the packets generated by host 172.16.3.3 because of the telnet,assuming the packets enter R1's F0/0 interface?（） interface Fastethernet 0/0 ip address 172.16.1.1 255.255.255.0 ip policy route - map Q2 ! route - map Q2 permit match ip address 101 set interface s0/0/1 ! access - list 101 permit tcp host 172.16.3.3 172.16.4.0 0.0.0.255A、The packet will be forwarded out S0/0 /1, or not at all.B、The packet will be forwarded out S0/0/1 if it is up.C、The packet will be forwarded out S0/1/1 if it is up.D、The packet will be forwarded out S0/1/1 if it is up, or if it is not up, out s0/0/1.E、The packet will be forwarded o ut S0/0/1 if it is up, or if it is not up, out s0/1/1.
In JUNOS Software， which three packet elements can be inspected to determine if asession already exists？（）A、IP protocolB、IP time-to-liveC、source and destination IP addressD、source and destination MAC addressE、source and destination TCP/UDP port
Firewall filters can perform which two actions？（）A、Log packet.B、Count packet.C、Set packet metric.D、Decrement packet TTL.E、Change destination IP address.
When an SRX series device receives an ESP packet, what happens?（）A、If the destination address of the outer IP header of the ESP packet matches the IP address of the ingress interface, it willB、If the destination IP address in the outer IP header of ESP does not match the IP address of the ingress interface, it willC、If the destination address of the outer IP header of the ESP packet matches the IP address of the ingress interface, based packet.D、If the destination address of the outer IP header of the ESP packet matches the IP address of the ingress interface, based of inner header, it will decrypt the packet.
单选题Which of the following commands provides data plane information required to forward a packet toa specific ip address？（）Ash ip routeBsh ip cef 〈ip_address〉Csh adjacency 〈ip_address〉Dsh ip route 〈ip_addres$〉Esh ip adjacency 〈/p_address〉Fsh ip cef 〈mac_addrQss〉〈ip_address〉
单选题Which statement correctly describes the disabling of IP TTL propagation in an MPLS network？（）AThe TTL field from the IP packet is copied into the TTL field of the MPLS label header at the ingress edge LSRBTTL propagation cannot be disabled in an MPLS domainCTTL propagation is only disabled on the ingress edge LSRDThe TTL field of the MPLS label header is set to 255EThe TTL field of the IP packet is set to 0
多选题If an edge Label Switch Router （LSR） is properly configured，which three combinations are possible？（）AA received IP packet is forwarded based on the IP destination address and the packet is sent as an IP packet.BAn IP destination exists in the IP forwarding table. A received labeled packet is dropped because the label is not found in the LFIB table.CThere is an MPLS label-switched path toward the destination. A received IP packet is dropped because the destination is not found in the IP forwarding table.DA received IP packet is forwarded based on the IP destination address and the packet is sent as a labeled packet.EA received labeled IP packet is forwarded based upon both the label and the IP address.FA received labeled packet is forwarded based on the label. After the label is swapped，the newly labeled packet is sent.
单选题When an SRX series device receives an ESP packet, what happens?（）AIf the destination address of the outer IP header of the ESP packet matches the IP address of the ingress interface, it willBIf the destination IP address in the outer IP header of ESP does not match the IP address of the ingress interface, it willCIf the destination address of the outer IP header of the ESP packet matches the IP address of the ingress interface, based packet.DIf the destination address of the outer IP header of the ESP packet matches the IP address of the ingress interface, based of inner header, it will decrypt the packet.
单选题Which command is used to debug a ping command?（）Adebug icmpBdebug ip icmpCdebug tcpDdebug 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.
问答题给了两段documentation里的描述，问这个时候发哪种类型的ICMP包。 The interface on which the packet comes into the router is the same interface on which the packet gets routed out. The subnet or network of the source IP address is on the same subnet or network of the next-hop IP address of the routed packet.
单选题Assuming that an IP packet is sent from a source address in VLAN1 to a destination address in VLAN2 through a layer-3 switch, which part of the packet will be changed?（）ALayer 2 TTLBLayer 3 TTLCLayer 3 source addressDLayer 3 destination address
单选题Which wireless LAN statistics are reported from the Cisco Unified Wireless IP Phone 7921G via a directly connected web browser?（）Aduplicate sender packetsBunicast packet retry rateCunicast packet retry ratioDassociation rejections
多选题Firewall filters can perform which two actions？（）ALog packet.BCount packet.CSet packet metric.DDecrement packet TTL.EChange destination IP address.