[Standards] s2s and gracelessly broken streams
fippo at goodadvice.pages.de
Tue Apr 3 06:52:15 UTC 2007
Matthias Wimmer wrote:
> Due to my experience servers that went down is only the cause for a very
> small fraction of wrong presences. Our main problem still seems to be,
> that even the user's server has a wrong impression of this user's
> presence (i.e. servers that do not detect that a user is not online
> anymore). We now have XEP-0199 that allows a server to probe if a client
> is still online. We should first see how much the problem of stale
> presences is improved if servers XEP-0199-pinging idle clients get more
> widely deployed, before we start tweaking less important factors.
I would suspect temporary s2s hiccups and 'lost' unavailable stanzas to
be another cause.
Whereas those stanzas are 'lost' in a situation like the following:
the user goes offline, the server does the unavailable presence
broadcast and something (*) goes wrong during s2s. The server will see a
<presence type='error' from='...' to='...'><error .../></presence>
and the information that this was an unavailable presence is lost,
hence there is no chance to resend it.
(*) for example your dns server refuses to work - the kind of bugs you
can hardly ever reproduce
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