TheabovecontentisreviewedandannouncedbytheNationalScienceandTechnologyTermReviewCommittee
Definition
ClassofService(CoS)networkisthenetworkAtechniqueormethodusedtodeliverqualityofservice(QOS).Specifically,CoSisamethodofclassifyingandprioritizingdatapacketsbasedonapplicationtype(voice,video,email,filetransfer,transactionprocessing,etc.),usertype(VIPorordinaryuser)orotherclassificationmethods,etc.."First-level"priorityflagsareassignedtodataapplications—suchasmission-criticaldatatransactions,orvideoorvoicetransmissions—thatchangequickly,andlow-priorityflagsareassignedtotime-sensitive,lesstime-sensitivetraffic,suchasE-mailandWebsurf.
Thedivisionofcommunicationqualitybasedontheprobabilityofacallbeingblockedordelayedformorethanacertaintime.Itisthecriterionofwhetheritisanincomingcallwhenitisbusy.
Relatedconcepts
Calllossrate
Whenmultiplechannelsareshared,becausethenumberofusersisgreaterthanthenumberofchannels,itmayhappenthatmanyusersrequesttotalkatthesametimebutthenumberofchannelscannotIftherequirementsaremet,onlyapartoftheuserscanbeallowedtotalkatthistime,andtheotherpartoftheuserscannottalk,untilthereisafreechannel,andthenlettheuserswhoneedtotalk.Therefore,althoughsomeusersmadeacall,butfailedtocompletethecallbecausethereisnochannel,thisiscalledacallfailure,thatis,a"callloss"occurs.
Fromtheperspectiveofachannel,evenifitcommunicatesuninterruptedlywithinanhour,theamountoftrafficitcancompleteisonly1Ireland.Sinceusersinitiatecallsatrandom,itisimpossibletousethechanneluninterruptedly,sotheactualvolumeoftrafficthatcanbecompletedbyachannelmustbelessthan1Ireland.Thismeansthatchannelutilizationcannotreach100%.Inthecaseofsharedchannels,itisdifficultforthecommunicationnetworktoensurethatallcallsofeachuseraresuccessful,andasmallamountofcallfailureswillbecalled"callloss".
Calculation
Servicequalityisanexpectationthatcustomerscanexperiencewhenmakingaphonecall.Inaloss-basedsystem,thequalityofserviceisdescribedastheratiooflossduringbusyhours.Foraninvalidcallsystem,thequalityofservicecanbecalculatedusingFormula1.
Foradelayedcallsystem,thequalityofserviceismeasuredbythefollowingthreepoints:
·1)Averagedelay-describestheaveragetimetheuser'srequestisdelayedwhilewaitingforaconnection.
·2)Averagedelay-Describetheaveragetimetheuserspendswaitingforaconnectionregardlessofwhetherthecallisdelayedornot.
·3)Theprobabilitythatausermaybedelayedlongerthantimetwhilestillwaitingforconnection.Thetimetisselectedbythetelecommunicationserviceproviderinordertomeasurewhethertheirservicemeetsthelevel.
Application
Servicelevelisasignoftheservicequalityoftelecommunicationsenterprises,animportantbasisfortheresearchdepartmenttodeterminethegroupstructureofswitchingequipment,andanimportantindicatorforthedesigndepartmenttomeasurethequalityoftelecommunicationsnetworkdesign.Thedeterminedservicelevelishigh,whichwillcauseawasteoffunds;whilealowlevelwillreducethequalityoftelecommunicationsservices.
Differenttelecommunicationsapplicationsrequiredifferentqualityofservice.Forexample,ifatelecommunicationsserviceproviderdecidestoprovidedifferentqualitiesfordifferentvoiceconnections,thenahigh-qualityvoiceconnectionwillhaveabetterconnectionqualitythananormalvoiceconnection.Inthisway,differentusesdeterminedifferentservicequality.Tohelptelecommunicationsserviceprovidersmarkettheirdifferentservices,eachserviceisplacedintoaspecificcategory.Eachserviceleveldeterminestherequiredservicelevel.
Accordingtothesurveyandresearchonthesametelephoneinthecity,thetotalcalllossis2to5%.Howtoallocatethetotalcalllosstoeachselectionlevelrequiresatechnicalandeconomiccomparison.Generally,thesensitivepartoftheuserisallocatedwithasmallercallloss.Forexample,thecalllossofstep-by-stepsystemandcrossbarsystemissetat0.5%whentheuserpicksupthephoneandlistenstothedialtone.Theselect-leveloutgoinglineisconnectedtotheinterofficetrunkline,andthelineinvestmentisrelativelylarge.Generally,itisallocatedto1%.Thecalllossrateatalllevelsofmycountry'slong-distanceautomaticnetworkbackboneroutingissetat1%.