SNMP Issue

Hi All,

While using cacti for SNMP polling for Mikrotik ( CCR, CRS, RB …), cacti shows all the snmp information, but shows the host down. No graphs are polled in that period. But it shows all the interfaces, ques etc. Any graphs can be added. If “Downed Device Detection” is set to ping ( Only ping), it shows up and works fine. Can any one tell why it is like that? One more question, SNMP V3 needs separate username for each SNMP poller host ( in case of multiple SNMP server for a single Mikrotik)?

Regards