Sum of values from discovered snmp items

[erghezi]

Hi
how can I graph all network traffic from discovered snmp items?
I want to monitor all network traffic of hotspot users in a wireless network . when I create a calculated item, everything works well until the the user logs off and when the item becomes available again the sum start from the first.
thanks

[Pada]

Doesn't there exist a SNMP OID that has the total, so that you don't need to sum all the values in Zabbix?

Alternatively, write a shell script to sum all the values.

[erghezi]

no I'm using a mikrotik router and it only has InOctets and OutOctets items for each hotspot user.
I set zabbix to keep discovered items in history for a year! but how can I force it to sum new values with historical data?
I can write a script to discover and sum values from snmpwalk but I have no idea how to sum this new values with historical zabbix data
thank you.