SRX

how to refer MIB and configure it , is there anyone who can give an example 

Can you explain a bit more what you want to achieve ?

i want the session usage ,and nat usage on NMS ,but when i finish confgure snmp, there is no data about that 

Which NMS are you using?

Typically you load the Junos MIB into the management console of the NMS and then select the desired parameters to monitor. 

on the device you only need to configure the version and community string that the NMS is using for the data collection.

ok .thank you very much . then in which situation we need to configure MIB on juniper device .

The MIB is a file used by other systems like an NMS or monitoring solution.  We don't use the MIB file on the Juniper device itself.  The MIB describes how to access SNMP parameters for monitoring.  And for industry standard settings you won't need the MIB loaded at all, these are usually built into the monitoring solution.

On the Juniper device we configure SNMP parameters that allow access to these settings by the monitoring solution.