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missing-protocol-http2

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Description

This rule determines if network protocol HTTP/2 is being used. The second iteration of the HTTP/1.1 protocol, known as HTTP/2, aims to address many of the issues with the previous HTTP/1.1 version in order to make applications faster and more robust. One of the ways in which HTTP/2 is faster is in how it prioritizes content during the loading process. HTTP/1.1 loads a single request for every TCP connection, while HTTP/2 avoids network delay by using multiplexing.

Some key features of HTTP/2 include:

  • Binary: HTTP/2 encapsulates data using a binary protocol. With HTTP/1.1, messages are transmitted in plaintext. That leads to the difference in the amount of data being transferred:
    Comparison amount of data being transferred
    HTTP/1.1 HTTP/2
    Uncompressed size 34.6KB 34.6KB
    Bytes transferred 28.2KB 21.4KB

    Given that the server settings were left unchanged, the automatic benefit is that the binary format has decreased the sent size by 7.4KB.

  • Multiplex: permits multiple requests and responses to be sent at the same time. HTTP/2 does this by splitting data into binary-code messages and numbering these messages so that the client knows which stream each binary message belongs to.
  • Compression: compresses headers that have been requested previously to make things more efficient.
  • Stream prioritization: this allows for the exchange of successive streams at one time.
  • Server push: The server can send additional information needed for a request before it is requested.
  • Increased security: HTTP/2 is supported through encrypted connections.
  • Header compression: every HTTP transfer contains headers that describe the sent resource and its properties. This metadata can add up to 1KB or more of overhead per transfer, impacting the overall performance. To solve that issue HTTP/2 uses HPACK compression to decrease the average size of the header.

SEO Benefits

Search engines like Google or Bing are all about page speed and they reward sites that improve their speed loading performance. One of the biggest SEO benefits of upgrading to HTTP/2 is that it will lead to faster loading, especially on mobile devices, resulting in a better user experience.

How to fix it

Standard

Best Practice, Performance, SiteLint

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