Is there a way we can capture device config just after device config change?
There is only set of devices on which I like to do this.
As per documentation we can use 'Unsolicited Capture', which I already configure but it not working as I am unable to see any trap or event for same.
Is there any way to do this, or how we can troubleshoot this? Do I need to configure anything on Device end and which type of trap Spectrum receive which trigger this capture real time?
First you need to make sure that you configured the device correctly to send traps whenever a configuration changes occurs.
Only after you receive the change event, make sure it's correctly interpreted by SPECTRUM (not identified as 0x10801, unknown event). Once you see this, you have to add your event for the configuration change to section "Configuration Notification Trap Settings" in the NCM family setup.