What is HTTP/2? Your Definitive Guide


HTTP (Hypertext Transfer Protocol) has evolved since its inception in 1991. By 1996, HTTP/1.1  had added features like metadata support, making it a flexible tool for online communication. There were several big improvements by 1999, including hosting multiple domains on a single IP address.

Fast forward to 2015 and HTTP/2, developed by the Internet Engineering Task Force. Several new features were added. They include fast, simultaneous loading from different resources, making it the latest standard. 

Read on to learn more about this development.

what is http2

What is HTTP/2?

HTTP/2 is a significant advancement in web protocols. It enhances web performance by optimizing bandwidth usage with features like header compression.

It also manages data transmission. This new protocol introduces multiplexing, allowing several requests to be sent over a single TCP connection.

HTTP/2 has server push. This feature speeds up page load times and even anticipates future requests.

The Basics of HTTP/2 Protocol

HTTP/2 is a binary tool.  That’s different from HTTP1.1. With the older system, each letter or request was sent and received one at a time. HTTP/2 uses a binary format that’s better for computers.

It breaks down communications into compact messages and simultaneously sends them over the same connection. This is called multiplexing.

Think of it as the difference between sending letters by mail (HTTP 1.1) and using a sophisticated telegraph system.

what is http2

Handling Multiple Requests Over a Single TCP Connection

HTTP/2 avoids the bottlenecks of HTTP 1.1, supplying faster web performance. Here’s how.

  •   It can handle multiple parallel requests over one connection, reducing load times for web pages.
  • Web content gets delivered quicker using flow control to manage the data’s transmission rates.

Think of HTTP/2 using one connection like a highway. Requests and responses are like cars that get put in different lanes in the same direction, so (web) traffic moves quickly.

what is http2

Server Push Feature in HTTP/2

This HTTP/2 push is a crucial improvement over HTTP 1.1.

  • This feature allows resources to be sent to clients’ browsers before they request them. Specifically, the server anticipates the need for images, JavaScript and other resources like CSS.
  •  Multiplexing allows the server to deliver resources without multiple connections.

Webpage loading times are decreased while resource delivery gets prioritized.

what is http2

Understanding Web Servers and HTTP/2

Web servers implement the features that HTTP/2 provides. Servers need to be configured to support it so they can manage resources and connections.

Adapting a Web Server for HTTP/2

Specific technical adjustments are required in the areas of header compression and flow control.

  • Flow control is used at the stream and connection levels. It uses a window-based approach and only allows users to send a certain amount of data. The server needs to buffer data when the window size is reached.
  •  Compressing headers reduces overhead, and HTTP/2 uses a certain specification called an HPACK. Compressing headers has security implications for the server that should be looked at.

Benefits of HTTP/2 for Web Servers

HTTP/2 has some specific benefits, including:

  1. Efficient resource utilization with multiplexing. Multiple requests and responses can be sent over a lone connection simultaneously.
  2.  Compression significantly reduces the amount of data transmitted.
  3. HTTP/2  is a binary protocol that’s less prone to error and more compact.
  4.  This protocol lets clients prioritize their requests so a server knows which resource to deliver first.
  5.  Flow control is independent of each stream for HTTP/2, which means resources get utilized more effectively.

Using HTTP/2 protocol offers significant improvements in web application performance, security, and user experience, making it a valuable upgrade for websites looking to enhance speed, efficiency, and overall service quality.

BenefitDescriptionTechnical AdvantageUser Experience Impact
Faster Page LoadReduced latency in data transmission.Utilizes multiplexing to send multiple requests over a single connection.Quicker website loading times for users.
Improved PerformanceEnhanced efficiency in data transfer.Binary framing layer improves the performance of data transfer.Smoother and faster interaction with web applications.
Server PushPreloading capabilities for faster access.Server can send resources proactively to the client.Immediate availability of content, reducing wait times.
Stream PrioritizationOptimizes processing of concurrent requests.Allows prioritization of resource loading.Critical resources are loaded first, enhancing the browsing experience.
Header CompressionReduces overhead in data requests.Uses HPACK compression to minimize header size.Decreases bandwidth usage and speeds up data transfer.
Improved SecurityEnhanced security features.Often implemented with mandatory encryption (TLS).Increases data security and privacy for users.
Resource OptimizationEfficient use of system resources.Reduces the need for multiple TCP connections.Optimizes server and client resource usage, benefiting large-scale websites.
Error HandlingBetter error detection and response.Improved mechanisms for managing connection errors.More stable and reliable web browsing experience.
Compatibility with HTTP/1.1Backward compatibility with legacy systems.Designed to work seamlessly with HTTP/1.1 protocols.Ensures accessibility to all users, regardless of their browser or system.
Reduced LatencyMinimizes protocol overhead.Lower protocol overhead compared to HTTP/1.1.Faster interactions, especially noticeable in high-latency networks.

what is http2

What is HTTPS Vs HTTP/2

 There are similarities and differences between HTTPS and HTTP/2. 

Security 

  HTTPS provides encryption to secure communication on the World Wide Web. The more modern version doesn’t provide this encryption, but it gets implemented over a TLS  or Transport Layer Security protocol. 

Performance 

HTTP/2 introduces several advancements, like compression for headers and server push. HTTPS doesn’t have these performance improvers.

Both are similar in that modern web servers and browsers widely support them. However, HTTPS enhances security by encrypting data, while its counterpart focuses on speed and efficiency.

what is http2

Security Aspects of HTTPS and HTTP/2

HTTP/2 adds performance enhancements to the encryption and security features found in HTTPS.

Performance Comparison Between HTTPS and HTTP/2

The most recent version enhances online performance over HTTP 1.1. Security isn’t compromised when HTTPS is implemented, either.

  • Bottlenecks are eliminated with multiplexing.
  •  Faster loading times are another bonus.
  •  Page loading speeds up since clients can prioritize requests.

what is http2

Implementing HTTP/2: Challenges and Considerations

There are real-world challenges and considerations for administrators and web developers adopting this protocol.

Overcoming Challenges in HTTP/2 Implementation

Configuring web browsers has a few different challenges. First, you need to ensure that your server software supports it.

You will likely need to set up TLS ( transport layer security). You’ll need to obtain and configure both TLS and SSL certificates.

Tweaking service settings related to TCP might also be in order. For example, look at the client-specific settings and the maximum number of concurrent streams.

what is http2

Considerations for Optimal Use of HTTP/2

Small businesses can leverage this effectively using the following considerations.

  •     Server configuration is critical because it has multiplexing and compression for headers as new features. Remember, this protocol requires a secure connection, so you’ll need to ensure you have updated SSL/TLS  certificates.
  •  Most modern browsers support this protocol, and that’s good for client compatibility. If you find some visitors are using older browsers that don’t support it, consider falling back to HTTP/1/1.
  •  Whether you’re maintaining or developing your website, it’s essential to use the tools optimized for the binary format of this protocol.

FAQs: What is HTTP2 Protocol?

Here are some of the common questions and answers around this protocol.

What Advantages Does HTTP2 Provide for a Web Server Over HTTP 1.1?

It uses HPACK, and that makes for encoded HTTP headers. That results in better use of bandwidth. Multiplexing allows for more efficient use of networking resources and faster data transfer without multiple TCP connections.

What is the Difference Between HTTP Protocol and Binary Protocol in HTTP2?

The most significant difference is that it uses a binary protocol, which is more efficient and reduces overhead. That’s the time needed to maintain a secure connection.

How Does a TCP Connection Work Differently in HTTP/2?

With this protocol, only a single connection handles multiple responses and requests.

Can HTTP2 Optimize Load Speed for Complex Websites?

Yes, efficient resource delivery and loading them over a single connection plus header compression make it possible.

Why is HTTP2 Not Widely Used?

One of the big reasons is the need to configure and upgrade server and client software.

Is There a Way to Tell if HTTP2 is Enabled?

 Browser developer tools can inspect the network and traffic of a given website to see if this protocol is being used.

Image: Depositphotos, Envato Elements

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Rob Starr Rob Starr is a staff writer for Small Business Trends. Rob is a freelance journalist and content strategist/manager with three decades of experience in both print and online writing. He currently works in New York City as a copywriter and all across North America for a variety of editing and writing enterprises.

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