combining replica placement and caching techniques in content distribution networks

《combining replica placement and caching techniques in content distribution networks》由会员上传分享，免费在线阅读，更多相关内容在教育资源-天天文库。

1、ComputerCommunications28(2005)1062–1073www.elsevier.com/locate/comcomCombiningreplicaplacementandcachingtechniquesincontentdistributionnetworksSpiridonBakiras*,ThanasisLoukopoulosDepartmentofComputerScience,HongKongUniversityofScienceandTechnology,ClearwaterBay,Kowloon,HongKong,Ch

2、inaReceived3May2004;revised16December2004;accepted10January2005Availableonline12March2005AbstractCachingandreplicationhaveemergedasthetwoprimarytechniquesforreducingthedelayexperiencedbyend-userswhendownloadingwebpages.Eventhoughthesetechniquesmaybenefitfromeachother,previousresear

3、chworktendstofocusoneitheroneofthemseparately.Inparticular,cachinghasbeenstudiedmostlyinthecontextofproxyserversystems,whilereplicationisthetechnologybehindContentDistributionNetworks(CDNs).InthispaperweinvestigatethepotentialperformancegainbyusingaCDNserverbothasareplicatorandasa

4、proxyserver.Wedevelopananalyticalmodeltoquantifythebenefitofeachtechnique,undervarioussystemparameters,andproposeagreedyalgorithmtosolvethecombinedcachingandreplicaplacementproblem.OursimulationresultsindicatethatasimpleLRUcachingschemecanimprovesignificantlytheresponsetimeofHTTPreq

5、uests,whenutilizedoverareplication-basedinfrastructure.Moreover,duetoitssimplicity,thishybridapproachdoesnotaffecttheadministrativeoverheadoftheCDNarchitecture.q2005ElsevierB.V.Allrightsreserved.Keywords:Replicaplacement;Caching;Contentdistributionnetwork(CDN);Hybridalgorithm;LRUm

6、odel1.Introductionpotentialbenefit:(i)thehitratioreportedintheliteratureistypicallybelow50%[1],and(ii)cachemisseswillnormallyTheexplosivegrowthoftheWorldWideWebandtheincuralargedelay,sincetheserequestswillhavetobeincreasingavailabilityoffastInternetaccesstotheend-user,redirectedtot

7、heoriginserver.haveturnedcentralizedwebserversintoaperformanceWhilecachingtriestominimizethelatencyofdown-bottleneck.Popularwebsites(e.g.newssites)receiveloadingthemostpopulardocuments,theunderlyingmillionsofHTTPrequestsperday,whichmayeasilyprincipleofreplicationistomovethewebcont

8、entasoverloadastate-of-the-artweb