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function of SNMP trap feature?

Posted: Sat Mar 20, 2010 4:18 pm
by RickyEM
I am a bit of a novice at networking etc but am enjoying your plugin which allows me to turn on and off a generator and wells at a remote solar powered ranch here in Arizona. I have one of the ippower sensors responding to the AC of the generator to tell me if it is on or not.

My question is what is the function of SNMP trap feature? I am not clear on what I could use it for.

Thanks

Re: function of SNMP trap feature?

Posted: Sun May 02, 2010 4:12 pm
by t006
There are two ways to use snmp.

1. Polling
Normally you poll a device or whatever every X minutes (snmpget/snmpwalk etc).

2. Traps.
You can also let the device send traps to the agent. Normally this is faster but unreliable because it is udp. You never know if the traps are received or not. But it is faster than polling.
Yes I know, with polling it is also udp but than the agent knows that there is no reply in case of troubles.

Re: function of SNMP trap feature?

Posted: Sun May 02, 2010 4:53 pm
by Rene
Polling the IPPower is not based on SNMP, so not using UDP (just for the record). Polling the IPPower might result in missing status changes of an input port if this status only last a shorter period than the poll interval. For instance, when the poll interval is 30 seconds and the event occurring only sets an input port to 1 for 5 seconds, you would miss this event. When SNMP traps are used, this event would have send a trap to the plugin. In your case where you are monitoring the status of the AC, which is on for a longer period I guess, polling works just fine.