[Standards-JIG] Smack Jingle Development - XEP for Media Proxy negociation

Jean-Louis Seguineau jean-louis.seguineau at laposte.net
Mon Oct 30 19:53:25 UTC 2006

Sometimes STUN, TURN and their combination in ICE will not be enough to get
the peer-to-peer communication to work.
This is where a passive media relay proxy comes handy. The proxy will figure
out the RTP IP and port from the first packet that arrives on the local RTP
IP and port of the proxy, and use it instead of using the RTP IP and address
declared in the negotiated transport. This trick solves the NAT traversal
problem, no matter how many NATs the client is traversing. However, the main
disadvantage is that, in some cases, the client will not receive early media
and it will not hear the ringing.

BTW this is exactly how Skype is doing, by using Skype clients that are not
behind NATs to proxy data for clients behind NATs...


-----Original Message-----
Date: Mon, 30 Oct 2006 11:30:46 -0700
From: Peter Saint-Andre <stpeter at jabber.org>
Subject: Re: [Standards-JIG] Smack Jingle Development - XEP for Media
	Proxy	negociation
To: Jabber protocol discussion list <standards-jig at jabber.org>
Message-ID: <454644D6.7000203 at jabber.org>
Content-Type: text/plain; charset="iso-8859-1"

What does the XMPP server know about media candidates? It's (mostly)
just an XML router. Since you're already talking to a STUN server for
ICE, it makes sense to get your media candidates from the STUN server
(i.e., via TURN), not from the XMPP server.

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