简介:Thenecessitytodistributethedataoverthewideareanetwork(WAN)tothephysicists'homeinstituteswillincrease,andtheeffectiveutilizationofthenetworkbecomescrucial,However,networksinthefutureWANwilltypicallyhavealargebandwidthatanorderofgigabitpersecond,withalatencyofseveralhundredssecondssothatthelargebandwidth-delayprodeuctextendstotensofmegabytesandnumerousproblemsareencountered.suchnetworksarecalled"longfatnetworks(LFNs)"Inordertostudythedatatransferoperatingonalongfatnetwork,wehavebuiltthePCclustersconnectedwiththerouterwhichcansimulatebandwidthlimitations.delays,packetlosses,andmultipatheffects.thisrouterisrunningonFreeBSDwithDUMMYNETkerneloption.Onthesemachineswehavemeasuredtheperformanceofthebulkdatatransfterwithnumerousconditionsandstudiedtheeffecienttransftermethods.