Togetherwiththenetworklayer,thetransportlayeristheheartoftheprotocol().Thenetworklayerprovidesend-to-end()deliveryusingdatagramsorvirtualcircuits.Thetransportlayerbuildsonthenetworklayertoprovidedatatransportfromaprocessona(请作答此空)machinetoaprocessonadestinationmachinewithadesiredlevelofreliabilitythatisindependentofthephysical()currentlyinuse.Itprovidestheabstractionsthatapplicationsneddtousethenetwork..Withoutthe()layer,thewholeconceptoflayeredprotocolswouldmakelittlesense.
A.connection B.terminal C.source D.destination正确答案C
