ABSTRACT
Transmission control protocol (TCP) is a part of TCP/Internet protocol (IP) suite [STD7,C02-1,F10, GW03,PD07].Itprovidesfulltransportlayerservicestoapplications.Itbelongstothetransportlayerin theTCP/IPsuitemodelasshowninFigure61.1.TCPismorecomplicatedthanuserdatagramprotocol (UDP)andprovidesareliableconnectionbetweenbothendsoftransmission.¥isconnectionneeds tobesetup,maintained,andtorndown.¥eprotocoldividesastreamofdataintounitsoflimited sizecalledsegments.¥esesegmentsarereassembledinareliablewayattheotherend.Reliabilityis achievedbyassemblingsegmentsbypreservingtheiroriginalsequence,andarrangingforretransmissionoflostorcorrupteddata.WhiletheunderlyingIPprovideslogicaladdressingofsegmentsandis responsiblefortheirtransmissionthroughnetworks[STD5],TCPprovidesadditionaladdressingthat allowssettingupconnectionsformultipleapplicationsandservicesonthesameend.Eachapplication seekingTCPconnectionisassignedoneormorenumbers(onenumberperconnection)thatarecalled port numbers. Figure 61.2 illustrates the concept of port numbers.
