基于j2me的手机通信功能的开发

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1、本科毕业论文英文翻译学院名称：计算机科学与通信工程学院专业班级：通信工程0501班学生姓名：指导教师姓名：指导教师职称：教授2009年3月RFC793-TransmissionControlProtocol2PHILOSOPHY2.1ElementsoftheInternetworkSystemTheinternetworkenvironmentconsistsofhostsconnectedtonetworkswhichareinturninterconnectedviagateways.Itisassum

2、edherethatthenetworksmaybeeitherlocalnetworks(e.g.,theETHERNET)orlargenetworks(e.g.,theARPANET),butinanycasearebasedonpacketswitchingtechnology.Theactiveagentsthatproduceandconsumemessagesareprocesses.Variouslevelsofprotocolsinthenetworks,thegateways,andthe

3、hostssupportaninterprocesscommunicationsystemthatprovidestwo-waydataflowonlogicalconnectionsbetweenprocessports.Thetermpacketisusedgenericallyheretomeanthedataofonetransactionbetweenahostanditsnetwork.Theformatofdatablocksexchangedwithintheanetworkwillgener

4、allynotbeofconcerntous.Hostsarecomputersattachedtoanetwork,andfromthecommunicationnetwork'spointofview,arethesourcesanddestinationsofpackets.Processesareviewedastheactiveelementsinhostcomputers(inaccordancewiththefairlycommondefinitionofaprocessasaprogramin

5、execution).EventerminalsandfilesorotherI/Odevicesareviewedascommunicatingwitheachotherthroughtheuseofprocesses.Thus,allcommunicationisviewedasinter-processcommunication.Sinceaprocessmayneedtodistinguishamongseveralcommunicationstreamsbetweenitselfandanother

6、process(orprocesses),weimaginethateachprocessmayhaveanumberofportsthroughwhichitcommunicateswiththeportsofotherprocesses.2.2ModelofOperationProcessestransmitdatabycallingontheTCPandpassingbuffersofdataasarguments.TheTCPpackagesthedatafromthesebuffersintoseg

7、mentsandcallsontheinternetmoduletotransmiteachsegmenttothedestinationTCP.ThereceivingTCPplacesthedatafromasegmentintothereceivinguser'sbufferandnotifiesthereceivinguser.TheTCPsincludecontrolinformationinthesegmentswhichtheyusetoensurereliableordereddatatran

8、smission.ThemodelofinternetcommunicationisthatthereisaninternetprotocolmoduleassociatedwitheachTCPwhichprovidesaninterfacetothelocalnetwork.ThisinternetmodulepackagesTCPsegmentsinsideinternetdatagramsa