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Re: Header compression: header set diff

From: James M Snell <jasnell@gmail.com>
Date: Thu, 21 Mar 2013 12:53:12 -0700
Message-ID: <CABP7RbfCyK8EFHt7g2s+uFhQHHPs3tv=2eunJ8rYDYgz2p=wmw@mail.gmail.com>
To: Patrick McManus <pmcmanus@mozilla.com>
Cc: ietf-http-wg@w3.org, RUELLAN Herve <Herve.Ruellan@crf.canon.fr>
+1.. In addition to this,  response headers tend to be significantly more
variable than request headers...  Which,  of course means much lower
compression ratios anyway if we're talking about delta based mechanisms.
It makes very little sense to optimize for the response side.
On Mar 21, 2013 6:14 AM, "Patrick McManus" <pmcmanus@mozilla.com> wrote:

> On Thu, Mar 21, 2013 at 8:50 AM, RUELLAN Herve
> <Herve.Ruellan@crf.canon.fr> wrote:
>
> > To better understand the impact of this choice of persisting the header
> set, we tested it inside HeaderDiff and saw a slight improvement of
> compaction for requests but also a slight(er) decrease of compaction for
> responses.
>
> All else being equal (which is of course never true), compression
> ratio of requests is more important than responses because the MUX
> allows multiple requests to fit inside the cwnd (and thus avoid
> scaling by rtt). The better the ratio, the greater the number of
> transactions in 1-flight-mux. On the response side the headers are
> mixed in with data frames which in many (but not all) scenarios
> overhwelm the headers on a byte count basis - so the effect of header
> compression is less likely to impact congestion control.
>
>
Received on Thursday, 21 March 2013 19:53:39 GMT

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