Can you tell me how to monitor network with below information.
Each user bandwidth usage and if increase(Like downloading movies, listing songs etc.) show alert
How to check Internet speed is fine for my company or should be increase any method ?
You are likely going to need a 3rd party piece of software or an appliance, the better ones are usually paid for.
Do you use active directory?
We use CA Netqos for the network provides all that information what users are using in bandwidth , the protocols etc , if you want to know exactly what websites there using , for how long and what there viewing specifically we use bluecoat which is not cheap but contains everything that your talking about.
What kind of security devices do you guys have? You are looking at Proxy solution. FirePOWER can provide the info as well and it can be integrated with ASA.