17.16.4 Operation principleThe Denial of service functions (DOSLAN1 and DOSFRNT) measures the IED loadfrom communication and, if necessary, limit it for not jeopardizing the IEDs controland protection functionality due to high CPU load. The function has the followingoutputs:• LINKUP indicates the Ethernet link status• WARNING indicates that communication (frame rate) is higher than normal• ALARM indicates that the IED limits communicationSection 17 1MRK 504 135-UEN ABasic IED functions600Technical manual