AnytimeahostorarouterhasanIPdatagramtosendtoanotherhostorrouter,ithasthe(请作答此空)addressofthereceiver.ThisaddressisobtainedfromtheDNSifthesenderisthehostoritisfoundinaroutingtableifthesenderisarouter.ButtheIPdatagrammustbe()inaframetobeabletopassthroughthephysicalnetwork.Thismeansthatthesenderneedsthe()addressofthereceiver.ThehostortheroutersendsanARPquerypacket.ThepacketincludesthephysicalandIPaddressesofthesenderandtheIPaddressofthereceiver.Becausethesenderdoesnotknowthephysicaladdressofthereceiver,thequeryis()overthenetwork.EveryhostorrouteronthenetworkreceivesandprocessestheARPquerypacket,butonlytheintendedrecipientrecognizesitsIPaddressandsendsbackanARPresponsepacket.Theresponsepacketcontainstherecipient'sIPandphysicaladdresses.Thepacketis()directlytotheinquirerbyusingthephysicaladdressreceivedinthequerypacket.
A.port B.hardware C.physical D.logical正确答案D
