What is Peer-to-Peer (P2P) Network?

A peer-to-peer (P2P) network is a network in which every connected device, called a peer or node, acts as both a client and a server. Peers request resources from each other and supply resources to each other directly, with no central server in the middle.

P2P networks power file sharing (BitTorrent), blockchain and cryptocurrency, online gaming, and video calls. Inside large companies, the same principle is used to deliver live video to thousands of employees at once without overloading the corporate network. This guide explains how a P2P network works, the main types, examples, security risks, pros and cons, and where peer-to-peer fits in enterprise video delivery.

A peer-to-peer network works in four steps:

1. Discovery. A new peer joins and learns about other peers, either from a tracker or bootstrap server (hybrid P2P) or by asking peers it already knows (pure P2P). Structured networks use a distributed hash table (DHT) so any peer can locate content by key.
2. Request. The peer asks the network for a file, a stream segment, or a resource. The request is answered by whichever peers hold it, not by one central server.
3. Transfer in pieces. Large files and video streams are split into small chunks. A peer downloads different chunks from several peers at the same time, which is why P2P transfers speed up as more peers join.
4. Sharing back. As soon as a peer holds a chunk, it can serve that chunk to others. Every consumer is also a supplier, so the network’s capacity grows with its size instead of shrinking.

In an enterprise video network, the same mechanism runs inside a browser: employees watching the same live town hall exchange video segments over the local network, so only a few streams need to cross the WAN link into each office.

A P2P network is a decentralized collection of devices connected directly to each other via the internet, allowing you to share and access files without the need for a central server. This type of system design is an alternative to traditional client-server networks, where a central server houses data and controls access for all users. In a P2P system, every participating device, or peer, acts both as a client and a server, making the peer network highly resilient and scalable.

Decentralization is a key trait of P2P software. It eliminates the single point of failure and potential performance bottlenecks associated with having a centralized server. This makes the P2P protocol particularly effective for file sharing, blockchain technology, and collaborative tasks. The nature of these networks also means you can enjoy direct communication with other nodes, which can be useful in applications like online gaming and distributed computing.

Each P2P application boasts several distinctive traits that set it apart from the traditional client-server model. It’s crucial to be aware of them when choosing your infrastructure.

• Decentralization: In stark contrast to client-server architecture, there is no central authority in peer networking. Each node is responsible for a slice of the network’s function, from file-sharing software to controlling the network architecture.

• File Sharing: P2P file sharing allows efficient distribution and access to files among distributed coworkers. You can observe this in both an unstructured P2P network, which doesn’t have a predefined infrastructure, and a structured P2P network, which organizes peers in a specific fashion to optimize searching and data retrieval.

• Resources Distribution: Resources such as processing power, disk storage, and network bandwidth are distributed among the nodes, contributing to potentially increased overall network capacity and resilience.

• Scalability: Without a centralized point of burden, a P2P network can typically scale comparatively well, growing as more peers join and contribute their resources.

• Performance: Since you can retrieve files from multiple peers simultaneously, performance can be more robust compared to downloading files within a client-server infrastructure, where network traffic congestion is often an issue.

• Security: Securing P2P can be a double-edged sword. While decentralization can lead to increased resistance against singular points of failure, the widespread distribution of files may increase vulnerability to malicious activities without proper safeguards.

In a peer-to-peer network you rely on many contributors rather than one server. That structure is what gives P2P its efficiency, scalability, and resilience.

P2P networks come in three types. Unstructured networks let peers connect at random and flood the network with requests, which is simple but slow to search. Structured networks organize peers with a distributed hash table (DHT) so each peer is responsible for a known slice of the content and lookups are fast. Hybrid networks keep a small central component, such as a tracker or signaling server, to help peers find each other, then hand the data transfer to the peers. Most enterprise video P2P systems are hybrid.

While P2P networks offer numerous benefits, they also come with inherent security risks that you and your provider need to address proactively. 

• Distributed Denial-of-Service (DDoS) Attacks: P2P networks are vulnerable to DDoS attacks where multiple systems flood the bandwidth of resources of targeted servers, causing the service to become unavailable.

• File Poisoning: Deliberate sharing of corrupted or malicious files can result in compromised security measures.

• Man-in-the-Middle Attacks: Attackers can intercept and alter communication between peers.

• Routing Attacks: Your data can be misdirected through compromised nodes, leading to data leaks or loss.

• Identity and Privacy Issues: Since P2P networks are decentralized, there is a heightened risk of your privacy being violated as your IP address becomes visible to other peers.

To guard against those threats, you need to gather data about device diversity and BYOD policies in your organization, as these will determine access frameworks and encryption policies. Vbrick will be set up to follow best practices right out of the box, but you can also fine-tune additional security measures for API access, network monitoring or vendor management if necessary.

Security Best Practices in P2P Networks

To counter these challenges, you should adopt rigorous security measures.

• Cryptographic Techniques: Use strong encryption to ensure data integrity and confidentiality.

• Access Control Mechanisms: Restrict unauthorized users from accessing your network or certain confidential data.

• Content Verification: Implement systems to verify file integrity and authenticity.

• Traffic Filtering: Utilize tools to identify and block malicious traffic.

• VPNs: A Virtual Private Network can shield your IP address, enhancing your privacy and security from censorship or surveillance.

Focusing on elements like cost-effectiveness, scalability, resilience, and performance, let’s discuss the most significant pros and cons associated with P2P networks.

Pros of a Peer Network

• Cost Savings: By design, P2P networks minimize the need for centralized servers, which can lower your initial and ongoing costs. You’ll find that the barrier to entry is reduced since each computer in the network can directly share resources.

• Efficiency and Performance: When sharing files in a P2P network, your access to resources like memory and files increases as more peers join. This scalable model can enhance resource sharing and overall network performance.
• Flexibility and Resilience: Since a P2P network lacks a central point of failure, it tends to be more resilient if a peer goes offline. Each node, or peer, can operate independently, increasing the network’s robustness.

Cons of a Peer Network

• Bandwidth Utilization: The very efficiency of P2P can become a drawback. As each machine acts as a server and a client, it can consume significant bandwidth, affecting individual systems’ performance.

• Lack of Centralized Control: With no central authority to oversee the network, it can be challenging to enforce security policies or backups across all nodes, making the network potentially vulnerable to various risks.

• Complex Resource Sharing: While simple setups are straightforward, networks requiring advanced sharing configurations can become complex to manage without adequate networking knowledge.

The right setup depends on how each site connects to your network. Offices with many viewers on one LAN benefit most from peer-to-peer. Sites with multicast-enabled networks can add multicast, and remote or VPN users are served by edge caching. Vbrick’s Universal eCDN combines all three so each location gets the method that fits it. Schedule a demo to see how peer-to-peer video delivery would work on your network.