5、epartoflife.AsacornerstoneoftheentirenetworkofIPv4hasbeenverymature.However,duetoitsownlimitations,hasbeengraduallyexposedthemanyproblemsandshortcomings.Oneofthemost prominentis theaddressspaceofIP willbeexhausted and themainroutingtable growingproblemtherefore,IETFIPv6wasdesigned
6、toreplaceIPv4.Asthenextgeneration InternetProtocol IPV6, comparedtoIPV4hasthefollowing characteristics: simplified header and extension; big enough address space and hierarchy address architecture; Plug and Play internet working; authentication and encryption on network layer; sup
7、port on service quality; better support on mobile communication. IPv6will replaceIPv4.TheentirenetworkfromIPv4transitiontoIPv6needforalongtime,thetwonetworkswillcoexistforalongtimeinthefuture.SoexploretheIPv4andIPv6connectivityandtransitiontechnologyhasimportantsignificance.Thispa