[Standards] Link-Local Messaging comments

Justin Karneges justin-keyword-jabber.093179 at affinix.com
Tue Mar 13 20:29:06 UTC 2007

> >   In section 6 it says that the stream opening should have no 'to' or
> > 'from' attributes. Which is kinda unfortunate. This means that when
> > someone opens a new connection to me, the only information i have is the
> > ip the connection originated from. If the machine where the connection
> > originated from has multiple presence, i'll have to wait untill the first
> > stanza containing a 'from' attribute is received before i can link a
> > connection to a presence.. If there would be a 'from' attribute in the
> > stream opening, it would obviously be much easier/elegant.

That's how the protocol works though.  If you depend on this attribute being 
present, then you'll lose iChat compatibility.

IMO, it makes a lot of sense for the stream to not identify a particular 
account during the initial negotiation.  Like s2s, Link-local simply links 
two systems, and identification of accounts is better placed in the stanzas 
themselves (which allows multiplexing of one TCP connection for many stanza 

Unfortunately, iChat doesn't multiplex chats over one connection like this.  
Instead, it explicitly ties a TCP connection to a contact.  For example, 
closing a TCP connection is considered to have a meaning similar to 
the "Gone" XEP-85 chat state.  Weird...  but this is how iChat works.

So, as much as we can talk about better ways of doing Link-local (what you 
did), or assumptions/possibilities about the current design (what I just 
did), it's all kind of moot if we want to retain iChat compatibility.

> Ah. I'll change that, since we modified it in rfc3920bis too:
> http://www.xmpp.org/internet-drafts/draft-saintandre-rfc3920bis-01.html#str

What was the rationale for this?


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