Re: [rtcweb] Interest and need for Websocket subprotocol - JSEP over websockets

Christer Holmberg <> Thu, 04 December 2014 04:46 UTC

Return-Path: <>
Received: from localhost ( []) by (Postfix) with ESMTP id AD89D1A0047 for <>; Wed, 3 Dec 2014 20:46:45 -0800 (PST)
X-Virus-Scanned: amavisd-new at
X-Spam-Flag: NO
X-Spam-Score: -4.2
X-Spam-Status: No, score=-4.2 tagged_above=-999 required=5 tests=[BAYES_00=-1.9, HTML_MESSAGE=0.001, RCVD_IN_DNSWL_MED=-2.3, SPF_PASS=-0.001] autolearn=ham
Received: from ([]) by localhost ( []) (amavisd-new, port 10024) with ESMTP id 2K1zgJ4fFjoc for <>; Wed, 3 Dec 2014 20:46:43 -0800 (PST)
Received: from ( []) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by (Postfix) with ESMTPS id 8DCCB1A0039 for <>; Wed, 3 Dec 2014 20:46:42 -0800 (PST)
X-AuditID: c1b4fb30-f79d66d00000744c-ad-547fe7307ab1
Received: from (Unknown_Domain []) by (Symantec Mail Security) with SMTP id 50.1B.29772.037EF745; Thu, 4 Dec 2014 05:46:40 +0100 (CET)
Received: from ([]) by ([]) with mapi id 14.03.0195.001; Thu, 4 Dec 2014 05:46:40 +0100
From: Christer Holmberg <>
To: "" <>, "Makaraju, Maridi Raju (Raju)" <>
Thread-Topic: [rtcweb] Interest and need for Websocket subprotocol - JSEP over websockets
Thread-Index: AQHQDyhJsWChRutFjkOILDb7zwIvO5x+IkQAgAAF7QCAALQUmg==
Date: Thu, 4 Dec 2014 04:46:39 +0000
Message-ID: <>
References: <> <> <>, <>
In-Reply-To: <>
Accept-Language: en-US
Content-Language: en-GB
Content-Type: multipart/alternative; boundary="_000_7594FB04B1934943A5C02806D1A2204B1D57743AESESSMB209erics_"
MIME-Version: 1.0
X-Brightmail-Tracker: H4sIAAAAAAAAA+NgFmpgkeLIzCtJLcpLzFFi42KZGfG3RtfgeX2IQctLHYuGjVdYLWb+fshm sfZfO7sDs0frs72sHkuW/GTy2LfEPIA5issmJTUnsyy1SN8ugSvj/NX77AUrgioOH25kb2A8 6trFyMkhIWAiMf3Ia2YIW0ziwr31bCC2kMARRon+SSZdjFxA9mJGiW2bVjB1MXJwsAlYSHT/ 0wapERGokDj66TcLiM0soC5xZ/E5dhBbWCBKomnKOWaImmiJHbOfQNlOEh/2TwarZxFQkTjz 5DtYnFfAV+LvzQ+sELs6mSRmb9jICJLgFLCTWPVrLyuIzQh03PdTa5gglolLNH1ZyQpxtIDE kj3noR4QlXj5+B8ryJ3MAvkS+3aEQswXlDg58wnLBEaRWUi6ZyFUzUJSBVFiIPHl/W0oW1ti 2cLXzBC2vkT3+9NMyOILGNlXMYoWpxYn5aYbGemlFmUmFxfn5+nlpZZsYgRG2cEtvw12ML58 7niIUYCDUYmH1/BcfYgQa2JZcWXuIUZpDhYlcd6F5+YFCwmkJ5akZqemFqQWxReV5qQWH2Jk 4uCUamAU6Vh/wvXdjt+6/8Sayk5ckC6U6c9Je3Pgy6f2j5GGsw5W7WXI3PWd48pfddXSwAgW XYNTdxZ4iL4tbMz+fSmrXff6tsjctpqNz785bDXLOxCQqf30Z4TNg3VL5RZKRrokHXY/wJT1 yPF6nVdCnoqPdLL2oU2rd6xrZnPS2PZL+r+nvao2528lluKMREMt5qLiRABBLqVlkwIAAA==
Cc: "" <>
Subject: Re: [rtcweb] Interest and need for Websocket subprotocol - JSEP over websockets
X-Mailman-Version: 2.1.15
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: Thu, 04 Dec 2014 04:46:45 -0000

Hi Ranjit,

For WebRTC access to IMS, there is no such thing as a "default protocol".

It is true that, inside IMS, SIP is used, but you can use whatever protocol you want to access   IMS, as long as the eP-CSCF (acting as a WebRTC Gateway) can map it into SIP.



Sent from my Windows Phone
Sent: ‎03/‎12/‎2014 21:02
To: Makaraju, Maridi Raju (Raju)<>
Subject: Re: [rtcweb] Interest and need for Websocket subprotocol - JSEP over websockets

Hello all

While I agree SIP over Websockets is default signaling protocol for
WebRTC while working with IMS, there could be scenarios where WebRTC
calls can get initiated from non SIP UAs like web browsers which do not
support SIP. Then in such cases, the following things could happen
1) the WebRTC client on the browser can use JSEP to send its signaling
information over WebSocket,
2) the JSEP message would then land on the WebRTC GW over WS.
3) This JSEP message would then be converted to a SIP message and then
sent to IMS core.
4) within IMS core, its a regular SIP message
5) Again in the reverse direction, WebRTC GW would convert SIP to JSEP
6) JSEP message is sent over Websocket to UE.

now we see JSEP messages getting exchanged over Websockets. so if the
websocket sub-protocol does not define the type as "jsep", then the
WebRTC GW would not know the incoming message type and hence may discard
it or its behavior may be uncertain.

Also the JSEP message needs to be enhanced to add more message types
(along with current OFFER / ANSWER) to be able to map it with standard
signaling protocol like SIP as defined in


On 2014-12-03 12:40 pm, Makaraju, Maridi Raju (Raju) wrote:
> + 1 for using SIP over WebSocket.
> FROM: rtcweb [] ON BEHALF OF Roman
> Shpount
>  SENT: Wednesday, December 03, 2014 12:38 PM
>  TO:
>  CC:
>  SUBJECT: Re: [rtcweb] Interest and need for Websocket subprotocol -
> JSEP over websockets
> Is there any reason you cannot use SIP over WebSocket
> ( [1])?
> Call signaling will require a lot more information then what is
> provided in JSEP. JSEP mostly deals with offer and answer processing.
> Signaling will also need to deal with things like who is calling, why
> they are calling, transfers, other application specific details. In
> other words, I think this is a very bad idea.
> _____________
>  Roman Shpount
> On Wed, Dec 3, 2014 at 1:31 PM, <> wrote:
> Hi
>  With websockets as a de-facto transport protocol for WebRTC signaling
> and JSEP being the format of encoding information, there is a need for
> a defining a websocket sub-protocol : jsep. So I would like to know if
> there is any interest in the community and also the views from experts
> about the need for a websocket-sub protocol for JSEP.
>  The main purpose of defining the sub protocol (jsep) is to make sure
> that the WebRTC client (WIC) and WebRTC server (E-CSCF) are receiving
> JSEP encoded messages.
>  Thanks
>  Ranjit
>  _______________________________________________
>  rtcweb mailing list
> [2]
> Links:
> ------
> [1]
> [2]

rtcweb mailing list