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1、Chapter4ENHANCEDSECURITYFORWIRELESSLANSANDWANSINTHEENTERPRISE:HANDSON1.INTRODUCTIONWLANsandWWANsareacommonelementinmanyenterprises'ITinfrastructures,butthesecuritypictureleavesmuchtobedesired.ThischapterwillhelpmanagersgetagraspofbasicWLANandWWANssecurit
2、yissues.2.WIRELESSLOCALAREANETWORKS(WLANS)WirelessLANsareabigpartoftheITworld.TherearefewITmanagersincorporateAmericawhohaven'tyetdippedtheirtoesintothewirelessnetworkingwaters.Takealookatthenumbers:SalesofWiFiclients(mobilePCs,PDAsandphones)grew77%in200
3、5,accordingtoindustryanalysts.WiFihardware(accesspointsandswitches)willsurpass$7billioninannualsalesin2006,and91%oflaptopPCsnowareshippedwithWLANcards[1].So,regardlessofwhetheryouareanewcomertowirelessLANsorarelookingtoupgrade,oneofthebiggestobstaclesyou
4、willhavetoworkthroughissecurity.Newwirelessstandards,moreawarenessandnewtechnologiesarerapidlyaddressingthatproblem;but,attheendoftheday,itwillbeyourjobtoevaluate,implementandmanagethewirelessnetwork.116Chapter4Therefore,withtheprecedinginmind,let'sbrief
5、lyseewhetheryouknowyourstandards.EventhoughtheywerecoveredextensivelyinChapter3,anupdateonWiFiisinorderhere~thefamilyofwirelessprotocolsthatformsthefoundationofmostWLANs.2.1KnowYourStandardsForexample,thenewestWiFiflavoris802.1Ig.Itjoins802.11band802.1la
6、.802.1Igoperatesinthesamefrequencybandas802.1lb(2.4GHz),soit'sinteroperablewithbdevices,butitallowsforthroughputof54Mbit/sec.asopposedtob's1IMbit/sec(Seesidebar,"WiFiTypes.")[1].Note:Withoverhead,interferenceandattenuationfactors,though,actualspeedsareus
7、uallyatleasthalftheclaimedpeak.WiFiTypesThefollowingWiFitypesareavailablenoworwillbesoon:•802.11a:5GHz,maximumspeed54Mbit/sec^:Doesnlworkwith802.11b.t802.lib:2.4GHz,maximumspeed11Mbit/sec.•802.11e:NewerstandardaddressesvoiceandvideoQoS.•802.11g:2.4GHz,ma
8、ximumspeed54Mbit/sec.Gonipatrblewith802.11b.k^•802.11r:Newerstandardthatsupports128-bt+encr^^ption.•802.1In:Stitfindevelopment;willtopl^l^it^s^^t802.11r:Stillindevelopment;willimprovevoiceQoSandroamingabilitfes[1].;Meanwhi
