SPDY

( Speedy of english, fast ',' nimble 'or' fast ' ) SPDY [ spi ː di] is an experimental, TCP - based network protocol, which was developed by company Google. SPDY is not intended to completely replace, but augment or replace individual components of HTTP. The in-process standard HTTP/2.0 was originally based on SPDY.

Operation

Each SPDY transmission is encrypted using TLS. Originally, the compression of the HTTP header was provided with gzip - but because of what has become known attack of CRIME no more should be done. A roughly twice as fast page reached according to Google SPDY mainly by the multiplexing of transmissions. This can be transmitted in parallel over a single TCP connection any number of documents. Here SPDY provides the ability to prioritize the individual requests in order to avoid a deadlock or to get important documents faster.

In addition, in SPDY, the server itself initiate transfers and send content directly and without request to the client ( server push). So updated content (eg, new e -mails) without reloading by the user or constant search scripts will be sent directly to the already loaded page, which then updates the corresponding regions. Linked to this, inter alia, the load times of other page views can be reduced and a better utilization of the network can be achieved since pointless queries account for suspicion.

Implementations

On the client side

Google Chrome was the first browser with SPDY support. Mozilla Firefox support SPDY, version 11; from version 13, it is enabled by default. Opera supports SPDY since version 12:10. SPDY is supported by about 0.5 % of all websites. As of version 11 and Windows 8.1 also supports Microsoft Internet Explorer SPDY.

If SPDY was used for transmission, is in response headers in Firefox, the entry " X - Firefox SPDY " with a value greater than or equal to 1 records.

On the server side

For the very popular Apache web server, there is a module called mod_spdy which the server provides the support SPDY. Also for nginx, used in some great service, there is an experimental module.

Criticism

The semantics of the server push contradicts According to Microsoft, the HTTP.

The mandatory encryption many ( transparent ) proxies will not work. A filtering of the transmitted content is greatly difficult.