HTTP/2 Delivery of Contents in AEM
HTTP/2 enables a more efficient use of network resources and a reduced perception of latency by introducing header field compression and allowing multiple concurrent exchanges on the same connection. It allows interleaving of request and response messages on the same connection and uses an efficient coding for HTTP header fields. It also allows prioritization of requests, letting more important requests complete more quickly, further improving performance. The resulting protocol is more friendly to the network, because fewer TCP connections can be used in comparison to HTTP/1.x. This means less competition with other flows, and longer-lived connections, which in turn leads to better utilization of available network capacity. Finally, HTTP/2 also enables more efficient processing of messages through use of binary message framing.
However, performance improvement of a site varies widely based on factors such as site’s code, how Dynamic Media is used, the client’s device, screen, and location, adobe’s own testing yielded interesting results — For images, response time improved 7%-28% depending on device and browser. The most notable performance gains were on iOS devices. PLUS load time performance improved up 15%.
Customers using AEM can be eligible for HTTP/2 based on conditions laid down by Adobe and enable HTTP/2 for their dynamic media. On request with required details, Adobe Customer Support adds them to the HTTP/2 customer waitlist based on the order in which requests were submitted.
However, there are few risks those need to be taken into consideration.
- The transition to HTTP/2 clears out your cache at the CDN because it involves moving to a new CDN configuration.
- The non-cached content directly hits Adobe’s origin servers until the cache is rebuilt again.
HTTP/2 and SPDY Indicator can be used on Chrome and Firefox to test if HTTP/2 is enabled.
