Re: HTTP/2 Push deployed on

Note that there is a thread on the Servlet EG list regarding an API for

where I've been asked some questions to describe "the rationalization used
by the httpbis wg"

Since I can't speak for the WG, I thought I'd echo my thoughts here
regarding the push mechanism to check that I'm not misrepresenting anything:

   - Push is a server-side coordinated mechanism in as much as the server
   must decide to push a resourced based only on information that it already
   has.   Specifically h2 provides no information on the contents or status of
   downstream caches.
   - Servers are free to innovate push strategies, with some of the
   following having been suggested:
      - Use knowledge from the web application/framework to determine what
      are associated resources.
      - Use heuristics derived from referrer headers and timing to infer
      what are associated resources
      - Use sessions to track what resources a client has
      requested/received to avoid unnecessary pushes
      - Use the presence of if-modified headers to infer the status of a
      client cache to avoid unnecessary pushes.
      - There are no functional problems other than increased latency of
   not pushing an associated resource
   - There are no functional problems other than wasted bandwidth of
   pushing an unnecessary resource:
      - Clients can reset a pushed stream if they determine it is
      unnecessary.   Thus is a server attempts to push a resource that
is already
      cached by the client, a RST will prevent wasting too much bandwidth.

Hopefully nothing controversial or misrepresented there?


On 18 August 2014 18:57, Simone Bordet <> wrote:

> Hi,
> the Jetty team has deployed h2-14 with HTTP/2 Push functionality on
>, see
> We are very interested in comments about how to make HTTP/2 Push
> better, so please try it out and tell us (also see discussion bullets
> towards the end of blog post).
> Thanks !
> --
> Simone Bordet
> ----
> Developer advice, training, services and support
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Received on Monday, 18 August 2014 23:55:32 UTC