You are deploying two core switches， one in each building， 50 km away from each other. The cross-connection between them will be a Layer 2 2-gigabit EtherChannel with an 802.1Q trunk. You configured it correctly but the link does not come up. The port is in the "admin up" state， and the line protocol is in the "down" state. The fiber link is OK. What would be the most likely reason for the link not to come up？（）

单项选择题DuringtheIPv6addressresolution，anodesendsaneighborsolicitationmessageinordertodiscoverwhichofthese？（）

A.The Layer 2 multicast address of the destination node
B.The solicited node multicast address of the destination node
C.The Layer 2 address of the destination node based on the destination IPv6 address
D.The IPv6 address of the destination node based on the destination Layer 2 address

多项选择题YourcompanyisresearchinganewapplicationthatrunsoverIPv6，butpartofitmuststillhaveIPv4support.YourcompanyusesatraditionalIPv4network.YourplanisnottorunIPv6overthewholenetwork，buttosegmentpartsofthenetworkoreventooperatesimultaneouslywithIPv6andIPv4.YoumustmakeabriefpresentationaboutIPv6technologytotheboardoftechnicaldirectors.Whichthreeoftheseitemscouldbepartofyourpresentation？（）

A.Tunnel IPv6 over IPv4 to connect far-end IPv6 networks.
B.Explain why configuring IPv4 and IPv6 at the same time over the same LAN interface is not possible.
C.Explain why configuring IPv4 and IPv6 at the same time over the same LAN interface is possible.
D.What is the meaning of EUI-64 and how does it work？
E.Tunnel IPv4 over IPv6 to connect far-end IPv4 networks.

多项选择题HalfofyournetworkusesRIPv2andtheotherhalfrunsOSPF.Thenetworksdonotcommunicatewitheachother.WhichtwoofthesefactorsdescribetheimpactofactivatingEIGRPovereachseparatepart？（）

A.EIGRP will not be accepted when configured on the actual RIPv2 routers.
B.OSPF will no longer be used in the routing table， because you only have EIGRP internal routes running.
C.OSPF will no longer be used in the routing table， because you only have EIGRP external routes running.
D.RIPv2 will populate its RIP database but not its routing table， because you only have EIGRP external routes running.
E.RIPv2 will populate its RIP database but not its routing table， because you only have EIGRP internal routes running.
F.OSPF database will have RIPv2 routes.

单项选择题WhatsthedefaultstratumclockonaCiscorouter，whenyouseethekeyword master configuredontheNTPline？（）

A.1
B.2
C.4
D.6
E.8

多项选择题ThecoreofanetworkhasfourroutersconnectedinasquaredesignwithGigabitEthernetlinksusing 30subnets.Thenetworkisusedtocarryvoicetrafficandotherapplications.Convergencetimeistakingmorethanexpected.WhichthreeactionswouldyoutaketoimproveOSPFconvergencetime？（）

A.Increase MTU of the interfaces to accommodate larger OSPF packets.
B.Change the network type to point-to-point on those links.
C.Reduce SPF initial timer.
D.Increase hello interval to avoid adjacency flapping.
E.Enable OSPF