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
正确答案是D