> I am new to dhcp , I have read out dhcp docs at internet, but not clearly understand in a practical way how dhcp works on a piece of harware.
> How it can be implemented on some harware or soc.
I doubt you could implement it in hardware - there's just so much involved. As both a primer and in-depth volume, I'd recommend you get hold of "The DHCP Handbook" by Ted Lemon and Ralph Droms. That will explain how the protocol works, and hopefully give you an idea of just how much is involved.
Apart from anything else, if you were to implement just DHCP in hardware, what would you use the information for if there wasn't a software stack to use it ?
So in reality, you'd be needing to use a full software stack - even if it was stripped down to the bare essentials. Once you are using software, then all the components are already written for you.
ISC funds the development of this software with paid support subscriptions. Contact us at https://www.isc.org/contact/ for more information.