Differences between HTTP/1.1, HTTP/2 and HTTP/3

Preface:

Today the Internet has become an important part of people’s lives, and the HTTP protocol (Hypertext Transfer Protocol) is the basis for supporting Web communications. With the development of Web technology and the increasing number of Internet applications, HTTP is also evolving. The purpose of this paper is to introduce three important versions in the evolution of HTTP:HTTP 1.1、HTTP 2andHTTP 3。

catalogs

Preface:

compiler

HTTP1.1：

Pros:

Drawbacks:

HTTP2:

Improvements for HTTP 1.1:

Drawbacks:

HTTP3：

Summary:

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HTTP1.1：

    HTTP 1.1（Hypertext Transfer Protocol 1.1）It is a protocol used to transfer data between a client and a server. It is the first major version of the HTTP protocol.HTTP 1.1 was released in 1999 and has been widely used and improved over the years.

Pros:

1. persistent connection: HTTP 1.1 introduced persistent connections, allowing multiple requests and responses over the same TCP connection. This reduces the time and resources required to establish and close the connection and improves performance.
2. pipelining: HTTP 1.1 supports pipelining, which allows a client to send multiple requests on a single connection at the same time without having to wait for previous responses. This reduces latency and increases efficiency.
3. chunked transport encoding: HTTP 1.1 supports Chunked Transfer Encoding, which allows the server to send a response in multiple chunks. This allows larger responses to be sent incrementally without waiting for the entire response to be generated.
4. cache control: HTTP 1.1 introduces stronger cache control mechanisms, including validation, expiration and revalidation mechanisms for caches. This reduces requests to the server and improves performance.
5. Web Hosting Support: HTTP 1.1 supports virtual hosts and can distinguish between different hosts by sending the Host field in the request header. This allows you to run multiple websites on the same IP address, improving the utilization of server resources.

Overall, HTTP 1.1 builds on previous versions with a series of improvements and optimizations that increase performance and efficiency, making web pages load faster and more reliably. It is still one of the most commonly used versions of the HTTP protocol on the Internet.

(indicates contrast)pipeliningThis technique can be a hard sell to front- and back-end developers, as pipelining allows for multiple requests to be sent at once but theWhen receiving requests, they must be received in the same order in which they were sentIf there is a packet loss at this point, then it will fall into a queue header blocking situation, which is reflected in the user interface, that is, the website page has not been able to open. This is a network protocol layer problem that can only be solved by the developer. And many websites use similar techniques as below to solve this problem: 1.Putting multiple resources into one packageFor example, originally three images to be packaged into three packages to send, in order to minimize the blocking of the queue header, we will put the three images into a single image, and only send the single image after this integration, the front-end staff to crop the 2.Base64 encoding of image resources, embedded directly into the HTML code so that this resource is not requested at the time of the request. 3.Set an image domain name for each imageThis allows browsers to receive at the same time, reducing the impact of header blocking. 4.Inline CSS, JS code into HTML code。 While the above methods are feasible, they also greatly increase the workload of developers, making it impossible for developers to focus on the development requirements in several ways.

Drawbacks:

1. Performance Limits: HTTP 1.1 uses a serial request-response model, where each request requires a separate connection to be established and responses must be returned in the order of the requests. This approach limits concurrency performance and throughput, especially when dealing with large amounts of resources.
2. latency issue: Since HTTP 1.1 cannot send multiple requests at the same time on the same connection, it is necessary to wait for the response of one request before sending the next one, which leads to a certain latency, especially in high latency network environments.
3. Head Redundancy: HTTP 1.1 needs to carry a lot of header information in each request and response, which may be duplicated in each request and response, resulting in unnecessary data transfer and waste.
4. Security issues: HTTP 1.1 communications are transmitted in clear text, making it easy for eavesdroppers to intercept and steal sensitive information. In addition, the lack of a built-in encryption mechanism makes HTTP 1.1 vulnerable to security threats such as man-in-the-middle attacks.
5. Inability to effectively utilize multi-core processors: Due to the request-response model of HTTP 1.1, each request needs to be processed sequentially, which cannot fully utilize the advantages of multi-core processors and affects the processing performance and efficiency.

Especially later, with the various browsers need to use HTTPS, that is, the need to HTTP using TLS locking, locking the TLS overhead caused by making HTTP1.1 is worse, so in a thousand calls, HTTP2 shine!

HTTP2:

        HTTP2（Hypertext Transfer Protocol version 2）is the second major version of the HTTP protocol, released in 2015. It is a major upgrade to HTTP 1.1, designed to improve performance, security and efficiency.

Improvements for HTTP 1.1:

1. Binary Framing): HTTP/2 transfers data in frames using a binary format, replacing the text format used by HTTP 1.1. This approach processes and transmits data more efficiently, reducing latency and bandwidth consumption.
2. Multiplexing: HTTP/2 introduces a multiplexing mechanism that allows concurrent requests and responses on the same TCP connection. This means that a client can send multiple requests at the same time and the server can return responses concurrently in any order, improving concurrency performance and resource utilization.
3. Header Compression: HTTP/2 uses theHPACKThe algorithm compresses the request and response headers. This drastically reduces the amount of data transmitted, decreasing latency and bandwidth consumption.
4. Server Pushing: HTTP/2 introduces a server push mechanism that allows the server to actively push relevant resources to the client upon receiving a request without the client having to explicitly request them. This improves the speed and performance of page loading.
5. Stream Prioritization (Stream Prioritization): HTTP/2 introduces the concepts of Stream and Priority, allowing different priorities to be set for different requests. This allows for more precise control and management of the order of requests and responses, optimizing response time and user experience.
6. Encryption Support: HTTP/2 recommends the use of TLS (Transport Layer Security) encryption for transmitting data, which increases the security of communication and protects user privacy and data integrity.

With these improvements, HTTP/2 has dramatically improved web page loading speed, concurrency and user experience. It has been widely supported and adopted as one of the key underlying protocols for modern Web applications.

The server push mechanism introduced in HTTP2, which seems excellent and greatly reduces the number of request responses, has a glaring vulnerability: After each point into the web page, the server will take the initiative to push the relevant resources to the client, which is obviously an unbalanced leverage relationship, we use a small number of clients can pry the server to push a large number of resources, which can be can be a window for DDOS attacks.

Drawbacks:

1. Infrastructure to be upgraded: The use of HTTP/2 requires both server and client support for the protocol. For large-scale and complex systems, upgrading and configuring the associated infrastructure may require some time and resources.
2. Increased complexity: The introduction of HTTP/2 has increased the complexity of the protocol. It involves new concepts, algorithms, and protocol mechanisms, which can be challenging for developers and system administrators to learn and implement.
3. compatibility issue: Although HTTP/2 has been widely adopted, there are still older versions of browsers and servers that do not support HTTP/2. To ensure compatibility, appropriate detection and fallback strategies are required.
4. Queue head blocking at the TCP level: HTTP/2 solves header blocking at the HTTP level, but still faces potential header blocking problems at the TCP level. tcp’s blocking control mechanism may result in the blocking of data transfers over the entire connection, which can affect performance.
5. Resource consumption for encryption: Since HTTP/2 recommends the use of an encrypted Transport Layer (TLS), this increases the computational and resource consumption for server-side processing and client-side decryption. This may have some impact on some resource-constrained environments and devices.
6. Security issues: Although HTTP/2 supports encrypted transmissions, misconfiguration or implementation may result in reduced security. Therefore, proper configuration and management of TLS implementations is critical to securing communications.

Despite a number of challenges and considerations, HTTP/2, a key protocol for modern Web applications, continues to offer significant advantages in providing better performance and user experience. Properly evaluating and applying HTTP/2, and using it in conjunction with other related technologies and best practices, can help maximize its benefits and address potential drawbacks. In order to solve these problems with HTTP2, HTTP3 was created

HTTP3：

HTTP/3 is called HTTP over QUIC (QUIC stands for Quick UDP Internet Connections). Unlike previous versions, HTTP/3 uses theNew transport layer protocol QUICto perform data transfer. [Knowledge Points Randomized Analysis | Part 5] A Brief Introduction to What is QUIC – Blogs HTTP/3 was designed with the goal of providing a faster, more secure, and more reliable Web communications experience. It usesUDP associationThe QUIC protocol provides better error recovery mechanisms and congestion control algorithms at the transport layer to minimize network latency and improve the efficiency of data transmission, instead of the traditional HTTP protocol based on TCP. Specifically, HTTP/3 introduces the following key features and improvements:

1. Quick Connection Establishment: QUIC uses the 0-RTT and 1-RTT modes of the handshake process to establish connections and perform security authentication faster, increasing page load speeds.
2. multiplexed: HTTP/3 supports concurrent transmission of multiple requests and responses over the same connection, allowing for more efficient resource utilization and lower latency.
3. Data Flow Optimization: By introducing traffic prioritization and header compression techniques, HTTP/3 can transmit data more efficiently, reducing bandwidth usage and network congestion.
4. error recovery: QUIC provides a more robust error recovery mechanism to recover lost data faster and provide more reliable communication quality.
5. Enhanced security: HTTP/3 uses a TLS-based encryption mechanism to protect the security and privacy of communications and to ensure the integrity and confidentiality of data transmission.

Overall, HTTP/3 aims to provide better performance, efficiency and security by introducing the QUIC protocol and a series of improvements. It addresses the shortcomings of the traditional TCP protocol in high packet loss and high latency network environments and promotes the further development of Web communications. With the gradual popularization and application of HTTP/3, users can expect a faster and smoother Web experience.

Summary:

HTTP 1.1 has many limitations in transferring data, such as orderly processing of multiple concurrent requests, high latency, and redundant repetition of headers. To overcome these problems, the HTTP standard-setting bodies and the Internet Engineering Task Force (IETF) initiated the development of HTTP 2. With a focus on performance, HTTP 2 introduces a number of improvements designed to increase the speed and efficiency of loading Web applications. It replaces the text format in HTTP 1.1 with a binary protocol, introducing new features such as multiplexing, header compression, server push and traffic prioritization. These improvements allow for more efficient data transfer between the browser and the server, providing faster page loads and a better user experience. However, as the Internet grows, new needs and challenges emerge. The traditional TCP-based HTTP protocol did not perform well in the face of high packet loss and high latency network environments. To address these issues, HTTP 3 was created, which introduces the QUIC (Quick UDP Internet Connections) protocol, which is based on the UDP protocol for transferring HTTP data, and provides more reliable and efficient communication through a new transport layer solution. HTTP 3 effectively solves the performance problems in network environments with high packet loss and latency. problems and drives further development of the Web.