通信工程专业英语教程.pptVIP

HowarepacketsmovedbetweenPOPs?ThepeeringthathappensatIXPsdependsonthebusinessrelationshipsbetweenISPs.Therearemanypossiblerelationships. InternetPackets**通信工程专业英语教程HowarepacketsmovedbetweenPOPs?ThepathapackettakesthroughtheInternetdependsonthepeeringchoicesoftheISPs.IftheISPdeliveringapacketpeerswiththedestinationISP,itmightdeliverthepacketdirectlytoitspeer.Otherwise,itmightroutethepackettothenearestplaceatwhichitconnectstoapaidtransitprovidersothatprovidercandeliverthepacket. InternetPackets**通信工程专业英语教程Vocabulary examine,access,fraction,difficultyStructureWritingtips如何表达方法、手段或途径Despite…/Inspiteof…Languageinuse**通信工程专业英语教程Vocabulary**通信工程专业英语教程examineexamine意为“仔细查看（以发现问题）”“签署合同前要仔细查看其条款”Don’tsignanycontractbeforeexaminingitsconditions.“此项研究考察了酒精对长期记忆的影响”Theresearchexaminedtheeffectsofalcoholonlong-termmemory.Academicwords**通信工程专业英语教程accessaccess可译为“访问”、“接入”“互联网接入”（Internetaccess）“接入点”（accesspoint）“你能否手机上网”（CanyouaccesstheInternetonyourmobilephone？）Academicwords**通信工程专业英语教程fractionfraction指“小数”或“分数”afractionof…指“一小部分……”“新系统可在零点几秒内查到电话通话”Thenewsystemcantraceaphonecallinafractionofasecond.Academicwords**通信工程专业英语教程difficultydifficulty作不可数名词时，意为“困难”difficulty作可数名词时，意为“难题”“一个没有预料到的难题出现了”Anunforeseendifficultyhasarisen.Academicwords**通信工程专业英语教程Technicalterms**通信工程专业英语教程Technicalterms**通信工程专业英语教程Technicalterms**通信工程专业英语教程Technicalterms**通信工程专业英语教程ARamanamplifierissketchedinFigure21.4.NotethesimilaritytoEDFA.RamanAmplifier**通信工程专业英语教程TheRamanamplifierispumpedinsuchawaythatthesignalandpumpbeamstravelinoppositedirections(counter-pumping).Becausetheattenuationofpumpbeamissosmall,ittravelsagreatdistance(severalkilometers)alongthefiber. RamanAmplifier**通信工程专业英语教程Therearea