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Re: hpack static table question?

From: Roberto Peon <grmocg@gmail.com>
Date: Mon, 2 Jun 2014 09:54:01 -0700
Message-ID: <CAP+FsNcfLy81yBef9bzUL3yNKQhLZRtqACYmY166DMPs6T8sBg@mail.gmail.com>
To: Greg Wilkins <gregw@intalio.com>
Cc: HTTP Working Group <ietf-http-wg@w3.org>
This was for safety. This ensures that entries in the reference set get
counted, even if the reference set is composed solely of members from the
static table.

This method was the simplest method for doing so.

-=R


On Mon, Jun 2, 2014 at 7:45 AM, Greg Wilkins <gregw@intalio.com> wrote:

>
> The hpack draft 7 says in 3.2.1 : "The referenced static entry is inserted
> at the beginning of the header table".
>
> I can't understand why this copy of a static entry to the dynamic table is
> needed?   Doesn't this mean that the static entry will now be known by two
> indexes?     Why is this copy needed?  Also If a badly written encoder kept
> sending the static index reference, then it would be possible to fill up
> the header table with duplicates of the static header?
>
> I'm also struggling to work out why the indexing is done like:
>
>           <----------  Index Address Space ---------->
>           <-- Header  Table -->  <-- Static  Table -->
>           +---+-----------+---+  +---+-----------+---+
>           | 1 |    ...    | k |  |k+1|    ...    | n |
>           +---+-----------+---+  +---+-----------+---+
>           ^                   |
>           |                   V
>    Insertion Point       Drop Point
>
>
> I would have thought it better to have the tables as:
>
>           <----------  Index Address Space ---------->
>           <-- Static  Table -->  <-- Header  Table -->
>           +---+-----------+---+  +---+-----------+---+
>           | 1 |    ...    | k |  |k+1|    ...    | n |
>           +---+-----------+---+  +---+-----------+---+
>                                  ^                   |
>                                  |                   V
>                             Insertion Point       Drop Point
>
>
> This looks like a very deliberate decision made for good reason... but the
> reason alludes me at the moment.
>
> cheers
>
>
>
>
>
>
>
>
>
> --
> Greg Wilkins <gregw@intalio.com>
> http://eclipse.org/jetty HTTP, SPDY, Websocket server and client that
> scales
> http://www.webtide.com  advice and support for jetty and cometd.
>
Received on Monday, 2 June 2014 16:54:29 UTC

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