Bandwidth cap

[KOA]

How can I set Bandwidth cap/ quota by user or by mac address or else by lan port, using dd-wrt on even better with the default firmware.

 

[uly]

Using dd-wrt, you can refer to this article:
How to reliably limit the amount of bandwidth your room mate or bad office colleague uses

You can also use a more advanced router such as the Cisco RV042 which you can control bandwidth based on IP address.