Re: Attn TorStatus folks! We are about to break your bandwidth measures!

["Kasimir Gabert" <kasimir.g@xxxxxxxxx>]

Hello Nick Mathewson,

Thank you very much for letting me know about this upcoming change.

I will get TorStatus to work with this new version, and release an
update, within the next few days.

2-4 weeks should be enough time to get most of the servers running the
new version of Tor and TorStatus.

Thanks again,
Kasimir Gabert

On 8/27/07, Nick Mathewson <nickm@xxxxxxxxxxxxx> wrote:
> Hi!
>
> So, for a long time, Tor servers put information in server descriptors
> that Tor clients didn't actually use.  The biggest offenders were the
> read-history and write-history lines: they account for around 60% of
> the size of a big set of compressed servers.  By removing these lines,
> we can save an enormous proportion of directory bandwidth, and (I
> hope) support more clients at a time.
>
> But what about the tools that use this information?
>
> Tor 0.2.0.x has a feature called "extra-info" documents.  This is an
> adjunct descriptor that gets published along side the main server
> descriptor.  Clients don't download it by default.  We now put
> bandwidth history information there.  Soon, extra-info documents will
> be the _only_ place to find bandwidth history information, once
> routers start omitting it from their regular descriptors.]
>
> [For the full details of the decisions involved above, see proposal
> 104 at
>   http://tor.eff.org/svn/trunk/doc/spec/proposals/104-short-descriptors.txt
> ]
>
> I'd like to get torstatus updated to handle extra-info before it starts
> getting bandwidth history.  To make this easier, I've added a GETINFO
> item:
>     GETINFO desc/all-recent-extrainfo-hack
>
> It gives the same result as desc/all-recent, except that it looks into
> any appropriate locally available extrainfo documents and adds
> bandwidth history lines that it found there.  (The signature is no
> longer valid, of course, but parsing should still work.)
>
> So, to keep torstatus's bandwidth history info from breaking, here's
> the procedure to follow:
>
>     1) Use Tor 0.2.0.6-alpha or later.
>
>     2) Switch GETINFO desc/all-recent to
>        GETINFO desc/all-recent-extrainfo-hack
>
>     3) Set "DownloadExtraInfo 1" in the tor process's configuration.
>
> (Later, it would be better to go back to GETINFO desc/all-recent, look
> at the extra-info-digest line in the original descriptor, and then
> GETINFO extra-info/<DIGEST> to get the bandwidth information.  But I
> wanted to provide something fast so that updating the code would be
> easy.)
>
> In all likelihood, servers will start dropping bandwidth history
> information from their descriptors in about 2-4 weeks from now.  Is
> that enough time?  We'd really like to get the directory bandwidth
> savings on the 0.2.0.x timeframe, but we don't want to break existing
> code in doing so if we can possibly help it.
>
> yrs,
> --
> Nick Mathewson
>
>


-- 
Kasimir Gabert