The source interface IP that receives UDP message. 255.255.255.255 from all IP interface. 0.0.0.0 - 0.255.255.255 and 127.0.0.0 - 127.255.255.255 not relevant addresses.
Sources for this description
Multiple manufacturers; see the original MIB MIB copies (LibreNMS/Observium Community)Dell MIB copies (LibreNMS/Observium Community)D-Link official switch MIBsNetdisco MIB archive copiesNETGEAR official product and EOL MIB downloads