Networkscanbeinterconnectedbydifferentdevicesinthephysicallayernetworkscanbeconnectedby()orhubs.whichjustmovethebitsfromonenetworktoanidenticalnetwork.Onelayerupwefindbridgesandswitcheswhichoperateatdatalinklayer.Theycanaccept()examinetheMACaddressandforwardtheframestoadifferentnetworkwhiledoingminorprotocoltranslationintheprocessinmenetworklayer,wehaveroutersthatcanconnecttwonetworks,Iftwonetworkshave(请作答此空)networklayer,theroutermaybeabletotranslatebetweenthepackerformats.Inthetransportlayerwefindtransportgateway,whichcaninterfacebetweentwotransportconnectionsFinally,intheapplicationlayer,applicationgatewaystranslatemessage().Asanexample,gatewaysbetweenInternete-mailandX.400e-mailmust()thee-mailmessageandchangevariousheaderfields.
A.special B.dependent C.similar D.dissimilar正确答案D
