HowmanymessagesdoesInternetKeyExchangeusetonegotiateSAcharacteristicwhenitrunsinaggressivemode？（）

<img src='https://img2.soutiyun.com/ask/uploadfile/2019-02-05/a12c70252f491d5177c66e822fdbcf0e.jpg' /> A.RouterC会使用ICMP通知Host1&amp;ldquo；Host2无法到达&amp;rdquo； B.RouterC会使用ICMP通知Host1&amp;ldquo；Host1无法到达&amp;rdquo； C.RouterC会使用ICMP通知Host1，RouterA和RouterB&amp;ldquo；Host2无法到达&amp;rdquo； D.RouterC会发送一个&amp;ldquo；DestinationUnreachable&amp;rdquo；的消息类型 E.RouterC会发送一个&amp;ldquo；RouterSelection&amp;rdquo；的消息类型 F.RouterC会发送一个&amp;ldquo；SourceQuench&amp;rdquo；的消息类型

A.Microsegmentationdecreasesthenumberofcollisionsonthenetwork. B.ifaswitchreceivesaframeforanunkowndestination，itusesARPtoresolvetheaddress. C.SpanningTreeProtocolallowsswitchestoautomaticallysharevlaninformation. D.Inaproperlyfunctioningnetworkwithredundantswitchedpaths，eachswichedaegmentwillcontainonerootbridgewithallitsportsintheforwardingstate.Allotherswitchesinthatbroadcastdomainwillhaveonlyonerootport. E.Establishingvlansincreasesthenumberofbroadcastdomains. F.Switchesthatareconfiguredwithvlansmakeforwardingdecisionsbasedonbothlayer2andlayer3addressinformation.

A．posturevalidationhasnotbeenenabled. B．theaaaserverissettoacceptbothms-chapv2andgtcforpeapauthentication. C．clientsandserverarenotusingcertificates. D．clientshavebeensettovalidatetheserveridentity.

A．A. 悬臂式排桩 B．B. 重力式水泥土墙 C．C. 土钉墙 D．D. 放坡

A五十元以下 B五十元以上二百元以下 C五十元以上一百元以下 D二百元以上