An 802.1Q trunk is not coming up between two switches. The ports on both switches are configured as "switchport mode desirable." Assuming that there is no physical issue，choose two possible causes.（）

单项选择题YoureplacedyourLayer3switch，whichisthedefaultgatewayoftheendusers.Manyuserscannotaccessanythingnow，includingemail，Internet，andotherapplications，althoughotherusersdonothaveanyissues.Alloftheapplicationsarehostedinanoutsourceddatacenter.Inordertofixtheproblem，whichoneoftheseactionsshouldyoutake？（）

A.Clear the MAC address table in the switch.
B.Clear the ARP cache in the switch.
C.Clear the ARP cache in the end devices.
D.Clear the ARP cache in the application servers.

单项选择题Refer to the exhibit. BGP-4 routing to the Internet，in normal behavior，may create asymmetrical routing for different prefixes. The BGP routing table indicates that traffic should follow the paths indicated in the exhibit，but packets are not going further than the border router in AS 4. What could be the cause of this problem？（）

A.TCP Intercept is configured in AS 4.
B.Unicast Reverse Path Forwarding is configured in loose mode in this router.
C.Packets may be leaving AS 1 without the BGP routing flag set to 1.
D.Unicast Reverse Path Forwarding is configured in strict mode in this router.
E.There is a missing Unicast Reverse Path Forwarding configuration.

单项选择题ArequestarrivedonyourMPLS-vpn-bgpgroup.Duetoasecuritybreach，yourcustomerisexperiencingDoSattackscomingfromspecificsubnets（200.0.10.0 24，200.0.12.0 24）.YouhavecheckedallMPLS-EBGProutesbeingadvertisedtoBHKfromotherVPNsitesandfoundfoursubnetslisted：200.0.10.0 24，200.0.11.0 24，200.0.12.0 24，200.0.13.0 24.YouimmediatelyapplyanoutboundACLfilterusingtheappropriateMPLS-EBGPtool：access-list1deny0.0.0.0255.255.254.255access-list1permitanyWhathappenswhenyouapplythisACLontheMPLS-EBGPconnectiontoBHK？（）

A.It blocks all routes.
B.It blocks the routes 200.0.12.0/24， 200.0.10.0/24 only.
C.It blocks the routes 200.0.12.0/24， 200.0.13.0/24 only.
D.It blocks the routes 200.0.10.0/24， 200.0.13.0/24 only.
E.Nothing happens， no routes are blocked.

单项选择题AnetworkiscomposedofseveralVRFs.ItisrequiredthatVRFusersVRF_AandVRF_BbeabletoroutetoandfromVRF_C，whichhostssharedservices.However，trafficmustnotbeallowedtoflowbetweenVRF_AandVRF_B.Howcanthisbeaccomplished？（）

A.route redistribution
B.import and export using route descriptors
C.import and export using route targets
D.Cisco MPLS Traffic Engineering

多项选择题ThenetworkadministratoristryingtoaddSwitch1tothenetwork，butthe802.1Qtrunkisnotcomingup.Switch1waspreviouslytestedinthelaboratoryanditstrunkconfigurationworkedfine.Whatarethreepossiblecausesofthisproblem？（）

A.The trunking configuration mode on Switch1 is set to Off.
B.The trunking configuration mode on the other end is set to On.
C.The trunking configuration mode on the other end is set to Desirable.
D.Cisco Discovery Protocol is not running on the other end.
E.There is a VTP domain name mismatch.
F.Switch1 does not support 802.1Q.