Peer to peer networks?
>How is it possible to write a peer2peer application.
Choose a programming language.
Obtain a compiler for your hardware platform.
Learn how to write software.
Write the software.
If you want to make an application that works over the internet then you need to read a few programming forums such as **broken link removed**. There are a few topics that get discussed every week such as dealing with connection sharing systems and firewalls that block incoming connections.
There is lots of information on the web about socket programming and thousands of posts in forums asking the same questions over and over again.
>is it possible to use a p2p application on a p2p hardware layer?
Yes.
>And is it possible to perform a hardware level p2p network?
Yes but not all applications of peer to peer networking can be easily implemented in logic gates rarther than software.