Peer to Peer Networks
When it comes to the term peer to peer network, also known as P2P networks, a picture appears – of a couple of computers connected directly to each other. They can be connected via the USB or via Ethernet cables. Suppose there are three computers A, B, and C, if A connects to B and B connects to C, the users of A can easily access files and printers connected to C, provided the computer C allows for file and printer sharing. It is just like the Homegroup network in Windows operating system.
In a peer to peer (P2P) network, a computer is both a client and a server at the same time. It is a client because it asks for data or any other service from a different computer to which, it is connected. It is a server because it provides access to the files on its hard disk or to the peripherals connected to it, to other connected computers.
A peer to peer network can also be implemented using a hub so that you do not need extra Ethernet cards to enable file and printer sharing. A hub could ideally be a router that has more than one LAN ports or a USB hub. See the image below for how it looks.
File Sharing Over Peer To Peer Networks
Peer to peer networks can be implemented locally or via the use of Internet. In the latter case, computers are not connected using Ethernet cables. Rather, they use normal Internet connections to connect to each other. If you have been using BitTorrents, you have been part of such a peer to peer network. File sharing in both types of P2P networks happens almost in the same way. Let us take a look at normal P2P home networks first.
You can select which folders to share by right clicking on the folder and going to the Share tab. The Share tab may be named different in different versions of Windows. You enable folder sharing by ticking the check box. In the drop down list that appears on the share tab, select Everyone. You can also select computers from the drop down list on the Sharetab and click Share to share a folder with select computers.
In short, the process of file and folder sharing in wired peer to peer networks is easier than you think. The computers are connected as soon as you connect them to the hub.
File Transfering via P2P on the Internet
This is where BitTorrent comes in. The protocol, BitTorrent, is used to download large files from the Internet. In case of BitTorrent, as soon as you initiate a download, your computer becomes a part of the Peer to Peer network on the Internet.
To be clear, a large file is not hosted on a single computer when it is available for download via BitTorrent. It is spread over multiple computers in form of different parts. When you use a .torrent file to download a file, you connect to more than one computer and your BitTorrent client downloads different segments from different computers that form a swarm(or a group of computers related to that download).
Your computer too is a part of that swarm as long as you are downloading as it establishes direct connection to different computers using the Internet. Also, as long as your BitTorrent client is running, it is seeding, i.e., uploading parts of the downloaded file to the Internet so that others who are trying to download the file at the same time, may download it from whatever your BitTorrent client is uploading. This is in addition to the peers (computers hosting parts of download, connected directly, without the need of a server in middle) from where the other user is receiving the file.
This explains Peer to Peer networking and file or printer sharing in layman’s language.