What is Peer-to-Peer (P2P) and How Does It Work?

March 22, 2024September 15, 2024

P2P (peer-to-peer) is a method of communication where data is directly exchanged between devices without the need for a server.

This article explains how P2P works, how it differs from the conventional client-server method, its advantages and disadvantages, and examples of its use.

TOC

What is P2P (Peer-to-Peer)?

P2P stands for ‘Peer to Peer,’ a communication method where data is directly exchanged between terminals such as PCs and smartphones, without requiring a server.

The term ‘peer’ refers to an entity of equal status or ability, like a colleague, in this context being a terminal connected to a network. These terminals are also known as ‘peers’ or ‘nodes.’ A network where these peers (or nodes) connect with each other using P2P technology is known as a ‘P2P network’.

Difference from client-server method

In addition to the P2P method, there is the conventional ” client-server” method of network communication.

The most significant difference between the two is the presence or absence of a centralized server. In the client-server method, known as the general communication method, the server provides data based on requests from the client (terminal) operated by the user. Websites that we usually access on the Internet mainly use this method.

In the P2P system, on the other hand, there is no server that centrally manages information, and data is retrieved and transferred directly between terminals connected to the network. Specifically, the terminal that possesses the information acts as the server, while the terminal that needs the information acts as the client and makes a data retrieval request to the terminal acting as the server.

P2P technology is used in cryptographic assets such as LINE and Bitcoin, as well as in file-sharing software.

Types of P2P (peer-to-peer)

There are three types of P2P

Pure P2P
Hybrid P2P
Supernode P2P

Let’s take a closer look at each of these.

Pure P2P

Pure P2P refers to a common P2P method in which files are retrieved and transferred directly between each node without a central server. Direct communication is performed between terminals with equal standing and functionality.

In pure P2P, which does not use servers, terminals distribute data and information among themselves and build an information network by compensating each other for missing data. Specifically, the terminal in need of information becomes the client, and information is obtained by making a search request to other terminals that have the information.

Hybrid P2P

Hybrid P2P refers to a communication method that uses a server in a conventional P2P network.

In hybrid P2P, the server manages the index information (i.e., which node has what information), while the actual data exchange takes place directly between nodes. This communication method is called a “hybrid method” because it combines the client-server method and the P2P method.

Supernode P2P

Super node P2P is a method in which node index information is managed by a special terminal called a super node.

Multiple terminals with excellent processing power and stable communication lines are selected as supernodes. The terminal selected as a super node manages the information of the nodes participating in the network and searches for necessary information in response to requests from each node.

Advantages of P2P (peer-to-peer)

P2P has three main advantages

Stable communication environment
Highly anonymous
Low-cost systems can be built.

We will explain in turn what it is all about.

Stable communication environment

The first advantage is the stable communication environment.

In the conventional client-server system, where information is managed and processed on a single server, clients cannot receive information if the server is down due to a concentration of accesses. This shutdown of the entire network due to server downtime is called ” downtime.

In contrast, the P2P method reduces the load on lines by distributing and managing data across multiple terminals, enabling faster communication than the client-server method. In addition, even if a particular client is down, the remaining active terminals can continue to communicate with each other, thus achieving ” zero downtime,” which means that the network is never down.

Highly anonymous

The second advantage is the high degree of anonymity.

In P2P, data is distributed across the network, making it difficult to know the information of all nodes and facilitating anonymity. The ability to communicate while maintaining privacy is a major advantage for network participants.

Low-cost systems can be built.

The third advantage is low-cost system construction.

The client-server method, in which data is managed by a specific central server, requires a high-performance server capable of processing vast amounts of information. In addition, running costs such as server maintenance and operation costs are also incurred, making the construction and maintenance of the system expensive.

On the other hand, P2P does not require a server, so the system can be built at a lower cost than the client-server method.

Disadvantages of P2P (peer-to-peer)

While it has the advantages just described, P2P also has the following disadvantages.

Virus spreads easily
Network bandwidth is easily overwhelmed

Each of these details is explained below.

Virus spreads easily

The first disadvantage is that viruses spread easily.

In P2P, data is exchanged directly between terminals without going through a server, so if there is a security problem at the connection point, there is a possibility of damage during communication.

Another disadvantage is that since countless PCs are connected like a mesh, viruses can easily spread throughout the network and it is difficult to identify the source of infection.

Network bandwidth is easily overwhelmed

The second disadvantage is that network bandwidth is easily overwhelmed.

Because data is sent and received intermittently with P2P, network bandwidth is easily overwhelmed. Therefore, while an application using P2P is in use, it may affect the communication environment for other applications.

Bitcoin and P2P (peer-to-peer)

Crypto assets, such as Bitcoin (BTC), use P2P communication methods.

Bitcoin employs a system in which funds are exchanged directly between users (P2P network) without the need for a bank or other administrator. All past transaction information is then recorded in a digital ledger called the blockchain, which can be freely viewed by anyone.

Since this blockchain is decentralized and managed by the nodes participating in the P2P network, the network can operate stably without system downtime even if some computers fail or are hacked.

In addition, because data is shared among many terminals, even if a malicious user attempts to tamper with the data, it can be detected immediately and hacking can be prevented.

Q&A on P2P (peer-to-peer)

Frequently asked questions about P2P are presented here in a Q&A format.

What is P2P?

P2P is an abbreviation for “Peer to Peer” and refers to a communication method in which files are exchanged directly between terminals (PCs, smartphones, etc.) without the need for a server.

What is the difference between client-server and P2P methods?

The most significant difference between the two is the presence or absence of a centralized server. In the client-server method, the server provides data based on requests from the clients (terminals) operated by the users.

On the other hand, in the P2P method, there is no server to centrally manage information, and data is directly retrieved and transferred between terminals connected to the network.

What types of P2P are there?