[Standards] XEP-0073: Question about service discovery

Robin Redeker elmex at x-paste.de
Wed Feb 7 14:29:08 UTC 2007

On Wed, Feb 07, 2007 at 02:38:58PM +0100, Remko Tronçon wrote:
> >And what about XEP-0073? It does not require XEP-0115 for the basic
> >protocol suite. So a client implementing only the basic protocol suite
> >will cause lots of flooding (he doesn't know how and what to cache
> >and so sends disco#info and jabber:iq:* requests to anyone).
> If a client can't do something without flooding (i.e. it doesn't want
> to implement entity caps), it shouldn't do it at all. So in this case,
> it shouldn't disco#info, unless the user requests it, or unless it
> really has to (e.g. for file transfer). A client should also never
> send jabber:iq:version to all his contacts, that's not nice (and yes,
> i know Psi has always had an option to do this until recently).

Ok, I agree with that :-)

> >Clients that implement XEP-0115 are said to aviod sending disco#info
> >if the other client does not send a <c> in his presence stanza. But this
> >will limit them, and they will get less information about the other
> >side (when playing nice and not send disco#info) than clients which
> >don't play nice will get.
> If you don't get caps information, assume that the other side can do
> everything. 

Then what are service discoveries (XEP-0030) and entity capabilities
(XEP-0115) for? I would assume that the other client does not support
anything beyond RFC3921 if it doesn't implement XEP-0115.

> >The natural conclusion would be: I use the new disco on capabilities
> >if the other side supports it and I will send disco#info if the
> >other side does not support entity capabilites.
> Send disco#info?

I meant: If I can't get enough information via capabilities I will still
have to send a simple disco#info query to the entity.

> >And about jabber:iq:version: Looks like clients will still flood them
> >if they want to display the OS the contact is using.
> Indeed. This should be against all recommendations, though. It's evil.

I haven't found a recommendation about this in any XEP yet. I might
missed it.


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