单项选择题 Youworkasanetworkengineerforthecompany，youwanttoconfiguretwoBGPspeakerstoformanEBGPsessionacrossafirewall.Ontheengineer’snetwork，thefirewallalwayspermitsTCPsessionsthatareinitiatedfromtheinsidenetwork（thenetworkattachedtotheinsideinterfaceofthefirewall）.WhatprerequisiteisthereforenablingBGPtorunonthisnetwork？（）
问答题 whatisthepurposeofframe-relayLMI？
单项选择题 MultiProtocolLabelSwitching（MPLS）isadata-carryingmechanismthatbelongstothefamilyofpacket-switchednetworks.ForanMPLSlabel，ifthestackbitissetto1，whichoptionistrue？（）