HTTP3 / QUIC Overview
QUIC is a general-purpose transport layer network protocol developed at Google and first deployed in 2012. It is designed to improve the performance of connection-oriented web applications as compared to TCP. It achieves this by utilizing multiplexed UDP connections, which allows data to be transported in multiple independent streams. This reduces the impact of any packet losses in one stream, as all of the other data streams can continue uninterrupted. QUIC also implements various other changes designed to reduce connection overhead and latency.
The HTTP mapping over QUIC is referred to as HTTP3, and is currently supported by Chrome (v87 and later), Microsoft Edge, Firefox, and Safari. Adoption of HTTP3 is expanding rapidly - most of Google's servers support it, as well as over 20% of the top 100 websites as of October 2021.
You can learn more about HTTP3 and QUIC here: https://quicwg.org
Catchpoint Support for HTTP3
Catchpoint supports testing for HTTP3 across the entire Node infrastructure in Web and Transaction tests using the Chrome monitor (version 87 or later.) There is nothing special you need to configure to enable HTTP3 in Catchpoint; simply configure a test using the Chrome monitor, and select version 87 or higher. The monitor automatically follows Chrome's HTTP3 implementation, which works as follows:
- Chrome connects to a remote host using HTTP2 (traditional TCP-based protocol)
- The response header from the remote host indicates support for HTTP3
- Chrome stores this information in its user profile folder
- Chrome sends subsequent requests to that host using HTTP3
This logic is followed for each host that the monitor connects to during a test run, so when viewing a Record that includes hosts which support HTTP3, you will see a mix of HTTP2 and HTTP3 traffic, as in the example below:
