AnytimeahostorarouterhasanIPdatagramtosendtoanotherhostorrouter,

AnytimeahostorarouterhasanIPdatagramtosendtoanotherhostorrouter,ithasthe()addressofthereceiver.ThisaddressisobtainedfromtheDNSifthesenderisthehostoritisfoundinaroutingtableifthesenderisarouter.ButtheIPdatagrammustbe()inaframetobeabletopassthroughthephysicalnetwork.Thismeansthatthesenderneedsthe()addressofthereceiver.ThehostortheroutersendsanARPquerypacket.ThepacketincludesthephysicalandIPaddressesofthesenderandtheIPaddressofthereceiver.Becausethesenderdoesnotknowthephysicaladdressofthereceiver,thequeryis(请作答此空)overthenetwork.EveryhostorrouteronthenetworkreceivesandprocessestheARPquerypacket,butonlytheintendedrecipientrecognizesitsIPaddressandsendsbackanARPresponsepacket.Theresponsepacketcontainstherecipient'sIPandphysicaladdresses.Thepacketis()directlytotheinquirerbyusingthephysicaladdressreceivedinthequerypacket.

A.multicast

B.unicast

C.broadcast

D.multiple unicast

正确答案是C