cucsSwEthMonDestEpRn (syntax SnmpAdminString) holds the Relative Name (RN) of this SPAN destination endpoint -- the naming component that distinguishes it from sibling instances of the same class under the same parent object. Since this SPAN destination endpoint is the destination endpoint of an Ethernet monitoring (SPAN) session -- the port that receives the mirrored traffic, several such instances can exist side by side under one parent, so the RN is what UCSM concatenates with the parent's DN to build this instance's own unique DN. For example, comparing the RN values returned for two sibling instances under the same parent tells an admin which specific one they are looking at without walking the full DN string.