January2014IEC61158-4-7(Firstedition–2007)Industrialcommunicationnetworks–Fieldbusspecifications–Part4-7:Data-linklayerprotocolspecification–Type7elementsCORRIGENDUM1AnnexC–Topologyofmulti-segmentDL-subnetworkReplacetheexistingtextoftheannexbythefollowing:AnnexC(informative)Topologyofmulti-segmentDL-subnetworkC.1IntroductionThisannexdescribeshowtospecifythetopologyofamulti-segmentDL-subnetwork.Theaimistoproposeadatastructure,whichcouldbeminimalwhileallowingcorrectoperationofthebridgeretransmissionfunction.ThetopologyofaDL-subnetworkcanfirstbespecifiedglobally,inordertoverifyacertainnumberofproperties(topologicalconnectivity,non-meshing,etc.);thenonthebasisofthisspecificationthelocaldatabasespecifictoeachbridgemustbecalculatedinordertoensureitoperatescorrectly.Althoughthisappendixproposesamethodtoachievethisgoal,onlythespecificationsofthedatastructures,globalorlocaltoeachbridge,whichdefinetheDL-subnetworktopology,aswellasthepropertieswhichitshouldfulfil,mustbetakenintoaccountinthestandard.Thesuggestedmethodshowshowtoobtainasolutiontotheproblembytakingintoaccountcertainoptimizationproblems.C.2GlobalspecificationThetopologyofamulti-segmentDL-subnetworkcanbedefinedbythefollowingelements:—thesetSofitssegments:[]{}nisSi,1∈=—thesetBofitsbridges:[]{}mkbBk,1∈=—andforeachbridgeofB,thedataofamatrixBkofdimensionn×n.whosecoefficientskijbaredefinedby:January2014—0=kijbifi=j;—∞=kijbifthebridgebkdoesnotallowtransferofmessagesfromsegmentsitosegmentsj;—α=kijbwith∈αR+*,ifthebridgebkallowsthetransferofmessagesfromsegmentsitowardssegmentsj,withαasloadcoefficientwhichallowstakingintoaccountofadifferentefficiencyrateaccordingtothetransfers.Aloadcoefficientkijbcanrepresenttheload,asarateofoccupationofthemedium,oftheretransmissionsegmentsj.Inreality,eitherthedestinationisdirectlysj,orthereareseveralpathspossible,passingthroughintermediatesegments,toreachsjandinthiscasethechoiceshallbetopassbytheleastloadedpath.Itisofcoursepossibletotakeascoefficientsthesamevalue(1forex...
