Foreachblank，choosethebestanswerfromthefourchoicesandwritedownontheanswersheet. ()isasixbytesOSIlayer2addresswhichisburnedintoeverynetworkingdevicethatprovidesitsuniqueidentityforpointtopointcommunication. ()isaprofessionalorganizationofindividualsinmultipleprofessionswhichfocusesoneffortonlower-layerprotocols. (请作答此空)functionswithtwolayersofprotocols.ItCanconnectnetworksofdifferentspeedsandcanbeadaptedtoanenvironmentasitexpands. ()isthepopularLANdevelopedunderthedirectionoftheIEEE802.5. ()isthepopularbackbonetechnologyfortransmittinginformationathighspeedwithahighleveloffaulttolerancewhichisdevelopedunderthedirectionofANSI.
A.The hub
B.The bridge
C.The router
D.The proxy
正确答案是B