Re: [rtcweb] RTCWeb default signaling protocol [was RE: About defining a signaling protocol for WebRTC (or not)]

Randell Jesup <> Mon, 19 September 2011 18:52 UTC

Return-Path: <>
Received: from localhost (localhost []) by (Postfix) with ESMTP id DB5CC21F8CD2 for <>; Mon, 19 Sep 2011 11:52:09 -0700 (PDT)
X-Virus-Scanned: amavisd-new at
X-Spam-Flag: NO
X-Spam-Score: -3.545
X-Spam-Status: No, score=-3.545 tagged_above=-999 required=5 tests=[AWL=1.054, BAYES_00=-2.599, GB_I_INVITATION=-2]
Received: from ([]) by localhost ( []) (amavisd-new, port 10024) with ESMTP id sBwmUW7+XIrj for <>; Mon, 19 Sep 2011 11:52:09 -0700 (PDT)
Received: from ( []) by (Postfix) with ESMTP id 6170421F8CDE for <>; Mon, 19 Sep 2011 11:52:09 -0700 (PDT)
Received: from ([] helo=[]) by with esmtpsa (TLSv1:AES256-SHA:256) (Exim 4.69) (envelope-from <>) id 1R5izB-00049D-20 for; Mon, 19 Sep 2011 13:54:33 -0500
Message-ID: <>
Date: Mon, 19 Sep 2011 14:51:11 -0400
From: Randell Jesup <>
User-Agent: Mozilla/5.0 (Windows NT 5.1; rv:6.0.1) Gecko/20110830 Thunderbird/6.0.1
MIME-Version: 1.0
References: <> <> <> <> <> <> <> <> <> <> <> <> <>
In-Reply-To: <>
Content-Type: text/plain; charset=ISO-8859-1; format=flowed
Content-Transfer-Encoding: 8bit
X-AntiAbuse: This header was added to track abuse, please include it with any abuse report
X-AntiAbuse: Primary Hostname -
X-AntiAbuse: Original Domain -
X-AntiAbuse: Originator/Caller UID/GID - [47 12] / [47 12]
X-AntiAbuse: Sender Address Domain -
Subject: Re: [rtcweb] RTCWeb default signaling protocol [was RE: About defining a signaling protocol for WebRTC (or not)]
X-Mailman-Version: 2.1.12
Precedence: list
List-Id: Real-Time Communication in WEB-browsers working group list <>
List-Unsubscribe: <>, <>
List-Archive: <>
List-Post: <>
List-Help: <>
List-Subscribe: <>, <>
X-List-Received-Date: Mon, 19 Sep 2011 18:52:10 -0000

On 9/19/2011 11:06 AM, Saúl Ibarra Corretgé wrote:
>>> That would require a signaling central point (think about
>>> NAT), does it mean that web sites should provide a like-"SIP proxy"
>>> within their infraestructure? (think about web sites hosted in shared
>>> datacenter by an Apache or other web server not behind the control of
>>> the web developer).
>> It would require a SIP proxy only if the app developer decides to use the SIP
>> module.
> I might be missing something, but how would Alice communicate with Bob if both are behind NAT and there is no server involved? Asking some IP and port out of band? I'm not aware of any Bonjour-style protocol for the Internet, is there something similar which could be leveraged?
> I see no clean way for 2 browsers to communicate without a server involved, and since it's not feasible to mandate that every browser manufacturer deploys one, I'd rather not have any simplified or default protocol.
You misunderstood me; I meant "if you use an optional SIP module, you'll
need to have a SIP proxy on your server".  WebRTC in general presumes some sort
of server architecture to solve the discovery/invitation problem.  There *are*
some possible uses of WebRTC that might not use a central server(s).   The simplest
would be the "phone-tag" server, where you and the person you want to talk to
exchange IP addresses and external port numbers over the phone, and type them into
the web app, which then opens a default-configured PeerConnection and re-negotiates
to the actual configuration.

Randell Jesup