Web pages, dynamic or not, are resource intensive. Browsers typically open one
or more TCP connections to an infrastructure to request resources. This
motivated the Internet Engineering Task Force (IETF) to pursue a new protocol
focused on network performance. In the process, other improvements were
adopted. HTTP/2 is the latest generation of HTTP protocols. The main body of
the new protocol was influenced and based on Google-sponsored SPDY.
HTTP/2 has several advantages over HTTP:
Messages are binary instead of textual.
Fully multiplexed, instead of ordered and blocking.
Everything happens in one connection.
Compressed headers.
Infrastructure can proactively push information/resources not requested by
clients.
Two protocols for SSL/TLS negotiation: NPN and APLN. The Acquia
platform uses OpenSSL 1.0.2g which supports both protocols.
Using the protocol and these features can reduce response time for websites.
Acquia supports HTTP/2 on its platform, with some exceptions. If you have a
compliant HTTP/2 client, no configuration is required.
Unsupported features
Acquia’s HTTP/2 implementation doesn’t support the following features:
Non-secure connections: TLS-protected requests are supported with HTTP/2
on Cloud Platform. Non-encrypted connections will always be served over
HTTP/1.1.
Elastic Load Balancers (ELB): Subscribers who have an ELB cannot use HTTP/2.
Infrastructure Push
CDNs
If your website is behind a CDN which supports HTTP/2, such as , it has HTTP/2 support. If your website is behind a CDN
that doesn’t support HTTP/2, you won’t.