How is WebSocket different from TCP?

Title: The difference between WebSocket and TCP and code sample analysis

1. Introduction
WebSocket and TCP are both network communication protocols, but they exist in some aspects Some differences. This article will explore the differences between WebSocket and TCP in detail and provide some specific code examples to help readers better understand the differences between them.

2. Basic concepts of WebSocket and TCP

1. WebSocket
   WebSocket is a protocol for full-duplex communication on a single TCP connection. It establishes the connection through a handshake phase and then maintains a persistent connection after the connection is established, which is used to pass messages between the client and the server.
   WebSocket is often used to implement real-time communication, chat, games and other applications. It can enable the server to actively push messages to the client and the client to actively send messages to the server.
2. TCP
   TCP (Transmission Control Protocol) is a connection-oriented and reliable transmission protocol, which ensures the reliability and orderliness of data transmission. After TCP establishes a connection, it confirms the establishment of the connection through a three-way handshake, then performs data transmission, and finally closes the connection through four waves of hands.

3. The difference between WebSocket and TCP

1. Connection establishment method
   TCP establishes a connection through a three-way handshake, ensuring the reliability of the connection between both parties. WebSocket establishes a connection through HTTP handshake, which is cheaper.
   Code example:

TCP connection establishment:

import socket

# 创建socket对象
tcp_socket = socket.socket(socket.AF_INET, socket.SOCK_STREAM)

# 连接服务器
tcp_socket.connect(('127.0.0.1', 8888))

WebSocket connection establishment:

let socket = new WebSocket('ws://127.0.0.1:8888');

2. Data transmission method
   TCP is a For the byte stream-oriented transmission protocol, when transmitting data, the data needs to be split into packets of appropriate size and then transmitted through TCP.
   WebSocket is a message-based transmission protocol that can encapsulate data into messages for transmission without splitting and assembling data packets.
3. Server Push Capability
   WebSocket can enable the server to actively push messages to the client, which is suitable for real-time communication, chat, games and other scenarios that require real-time push.
   TCP requires the client to actively request the server, and then the server responds to the client's request.
4. Data transmission efficiency
   Since WebSocket maintains a persistent connection after establishing a connection, multiple data transmissions can be performed while the connection is maintained, so the communication efficiency is higher.
   And TCP needs to close and re-establish the connection after each request and response. The overhead of multiple connections will lead to low communication efficiency.

4. Summary
This article compares the differences between WebSocket and TCP in terms of connection establishment method, data transmission method, server push capability and data transmission efficiency. WebSocket has low connection cost, supports server push, and has high communication efficiency. It is suitable for real-time communication scenarios; while TCP is more suitable for request and response mode scenarios.

It should be noted that WebSocket is based on TCP. It performs a handshake through the HTTP protocol and then upgrades to the WebSocket protocol. Therefore, compared to TCP, WebSocket is slightly inferior in reliability.

Therefore, when choosing whether to use WebSocket or TCP, you need to make a specific choice based on actual needs and scenarios.

Reference:

1. RFC 6455 - The WebSocket Protocol
2. RFC 793 - Transmission Control Protocol

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