[Standards] Jingle gateways, Stanza Session Negotiation and Service Discovery

Paul Witty paulrw at codian.com
Wed Apr 23 10:04:24 UTC 2008

Peter Saint-Andre wrote:
> Paul Witty wrote:
>> From what I can tell, XEP-0155 helps to get around this.  However, it
>> would be nice to include the ability to not just share presence, but to
>> also share service discovery information.
> As an option in the XEP-0155 negotiation? That seems sensible. Does it
> need to be a separate option or shall we assume that if you want to
> share presence you're also willing to share service discovery data?
> Probably it's best to make it explicit.
There needs to be a way to indicate that we are doing XEP-0155 in order 
to find presence and service discovery.  As it stands, all we can do is 
say that we may want to share presence, but the far end is under no 
obligation to do so.  While this makes sense for a text chat, if we want 
to start a Jingle session we can't do anything without presence and 
service information.  There should be a way that we say presence and 
service discovery (and perhaps Jingle) are required in this session, so 
that the client can reject/ignore the request immediately.

To make my life easier, something could be added to XEP-0166 saying that 
clients supporting Jingle should support XEP-0155, or even something 
similar to XEP-0155 but much lighter weight.
>> I've not yet tried doing this; it may be that it's entirely the wrong
>> way to go about it, so if anyone can suggest a better way, please speak
>> up.  For example, I'd like it so that one person could have many
>> different ways to be contacted e.g. H.323 endpoint, Jingle/XMPP client
>> on their desktop, Jingle/XMPP client at home.  We can't know in advance
>> what XMPP resource the user will have, so we want to just store the IP
>> address of their H.323 endpoint (e.g. and their XMPP ID, and
>> then connect to whichever resource is currently available.
> If you don't have any existing relationship with me and my server lets
> you know what my resources are, I would consider that to be a leak of
> private information. So I realize this is a pain, but sharing presence
> and resource information with unknown entities is widely considered to
> be a leak in the XMPP world. So we need to work around that, which we
> can do with XEP-0155, presence subscriptions, RAP (XEP-0168), etc.
I'm all for this, but I think that we should give the client the choice 
to allow incoming sessions from unknown clients, rather than having the 
server reject everything outright.



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