HTTP/2 Support

General

HTTP/2 is a major revision of the hypertext transfer protocol (HTTP) used in the World Wide Web. The protocol was derived from an experimental protocol named SPDY, introduced by Google, before it was published as RFC 7540 in 2015.

When designing HTTP/2, the inventors put their focus on efficiency. For that reason, the protocol offers a series of improvements over HTTP/1.1:

• HTTP/2 uses only one connection between client and server. This single connection supports multiple communication streams in parallel, which reduces the overhead for establishing multiple connections between client and server. In contrast: An HTTP/1.1 connection only allows simple request/response patterns.
• HTTP/2 is a binary protocol. As such it is not readable as opposed to HTTP/1.x.
• HTTP/2 uses a compression method that has been specifically designed for HTTP headers. This compression method takes into account that often very similar headers get sent over and over again.
• HTTP/2 allows a server to push resources to the client without an explicit request from the client.

Configuring HTTP/2

The Silk Performer HTTP/2 support is disabled by default. You can enable and configure HTTP/2 in the Profile Settings: Click Settings > Active Profile > Web (Protocol Level).

Limitations

Currently, Silk Performer supports HTTP/2 for replay only. Scripts recorded using HTTP/1.1 will replay correctly with HTTP/2 unless the server returns specific content that depends on the HTTP version the client uses.

The Silk Performer Recorder does not allow a browser to use HTTP/2, thus HTTP 1.1 is used. In most cases, this does not affect the recorded traffic and content. If however the server returns different content depending on the HTTP version used for communication, the HTTP/2 content cannot be recorded.