[Standards] s2s and gracelessly broken streams

JD Conley jd.conley at coversant.net
Mon Apr 2 20:04:28 UTC 2007

> Let me rephrase that:
> The reason why we do not want to keep high number of open connections
> is
> that the number of open connections would be high.
> This really does not answer my question. :-)

I think this is best answered in the form of a question: How well do you
think SMTP would scale if it held open connections for every domain that
is in your address book?

There is a finite number of connections you can use per IP address. In a
32 bit process space sometimes this TCP/IP imposed limit isn't even
achievable. In Windows, at least, you have to have kernel reserved
memory available for every socket connection (I would guess it's the
same in the *nix world). Holding a connection open is resource
intensive. Why not have that physical memory available for other, more
important things, than managing a stale connection. As the popularity of
XMPP increases the number of openly federated services will also
increase. If we did not tear down stale s2s connections, I could see
even small organizations (i.e. low thousands of simultaneous users -
like jabber.org) needing more than one IP address and more advanced
software configurations for their publicly federated XMPP system.


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