• the fact that at least one user has tried to log on wrongly into the IED and it wasblocked (the output USRBLKED)• the fact that at least one user is logged on (the output LOGGEDON)Whenever one of the two events occurs, the corresponding output (USRBLKED orLOGGEDON) is activated.17.16 Denial of service17.16.1 FunctionalityThe Denial of service functions (DOSLAN1 and DOSFRNT) are designed to limitoverload on the IED produced by heavy Ethernet network traffic. The communicationfacilities must not be allowed to compromise the primary functionality of the device.All inbound network traffic will be quota controlled so that too heavy network loadscan be controlled. Heavy network load might for instance be the result ofmalfunctioning equipment connected to the network.17.16.2 Denial of service, frame rate control for front port DOSFRNT17.16.2.1 IdentificationFunction description IEC 61850identificationIEC 60617identificationANSI/IEEE C37.2device numberDenial of service, frame rate control forfront portDOSFRNT - -17.16.2.2 Function blockDOSFRNTLINKUPWARNINGALARMIEC09000133-1-en.vsdIEC09000133 V1 ENFigure 264: DOSFRNT function block17.16.2.3 SignalsTable 511:DOSFRNT Output signalsName Type DescriptionLINKUP BOOLEAN Ethernet link statusWARNING BOOLEAN Frame rate is higher than normal stateALARM BOOLEAN Frame rate is higher than throttle state1MRK 504 135-UEN A Section 17Basic IED functions597Technical manual
