Understanding Web Sockets and Their Benefits

Web Sockets offer a high-throughput solution for real-time communication between a client and a server. Unlike traditional HTTP, which is designed for stateless, request-response interactions, Web Sockets enable a persistent, two-way communication channel. This makes them ideal for applications that require frequent or real-time updates, such as chat applications, live streaming, and online gaming. In this article, we explore how web sockets work and why they are advantageous.

How Web Sockets Work

Web Sockets operate over a single, long-lived TCP connection. This is achieved through an HTTP handshake, which upgrades the request from an HTTP connection to a WebSocket connection. During this process, the client sends an HTTP request with a specific upgrade header, and the server responds with an upgrade status, confirming the transition to a WebSocket session. The client and server then maintain this connection for as long as the application requires, allowing for real-time bidirectional communication.

Technological Overview

Let's compare Web Sockets with other technologies that are commonly used for real-time communication, such as HTTP, AJAX requests, WebRTC, and HTTP/2.0.

HTTP Requests

HTTP resources like .css, .js, .html, .jpg, and .mp4 files are handled through a multiplexed connection. Multiple requests can be made using a single TCP connection, but each new request must wait for the previous one to complete. This introduces a "head-of-the-line" blocking problem, similar to TCP's flow control. The flow control is applied to the entire request-response lifecycle, rather than a single packet.

AJAX Requests

AJAX requests involve additional Cross-Origin Resource Sharing (CORS) restrictions, often requiring an additional round trip to verify permission. This can introduce latency and reduce the efficiency of real-time data exchange.

WebRTC

WebRTC uses UDP for peer-to-peer communication. Unlike TCP, UDP is not designed for reliable data transmission and lacks flow control. WebRTC transmits small data packets at a consistent rate, making latency less of an issue but adding concerns about packet loss and internet relays.

HTTP/2.0

HTTP/2.0 introduces multiplexing, allowing multiple requests to be made over a single TCP connection without head-of-line blocking. This significantly reduces the number of round trips needed to fetch assets, improving page load times. However, server-push is only useful if the server is purpose-built for this purpose.

Web Sockets and Their Advantages

Web Sockets open a dedicated TCP connection, which maintains state and can be upgraded from an HTTP handshake. This connection is kept alive, allowing for sustained and efficient communication. Several features make Web Sockets preferable over other methods:

Non-blocking Communication: Web Sockets enable non-blocking communication, where data can be sent and received immediately. This is less feasible with HTTP polling or long polling, as they rely on client-side requests and server-side processing. Low Overhead: Web Sockets use a compact binary frame marker, reducing the overhead compared to ASCII headers. This is particularly beneficial in large-scale deployments. Flexibility: Web Sockets can send and receive multiple message types concurrently, allowing for complex applications like real-time collaboration tools. Scalability: Web Sockets can handle millions of idle connections without significant overhead, making them cost-effective for large-scale applications. Integration: Web Sockets can be integrated with cookie-based routing, enabling efficient data handling for large and small data sets.

Conclusion

Web Sockets offer a powerful solution for real-time communication, providing a persistent, two-way communication channel. Their ability to maintain long-lived connections and handle real-time data makes them ideal for a wide range of applications. By understanding how Web Sockets work and their advantages, developers can leverage their full potential to build highly responsive and efficient applications.