Subject: [sipcore] WebSocket in a Browser and outside it (was Re: draft-ibc-sipcore-sip-websocket-02.txt )

From: Salvatore Loreto <[email-masked]>
Date: Sun, 29 Apr 2012 20:02:30 +0200

5.2.3.  Sending Responses

    This specification updates the section 18.2.2 "Sending Responses" in
    [RFC3261] by adding the following:

    o  If the Via "sent-protocol" is "WS" or "WSS" the response MUST be
       sent using the existing WebSocket connection to the source of the
       original request that created the transaction, if that connection
       is still open.  If that connection is no longer open, the server
       SHOULD NOT attempt to open a WebSocket connection for sending the
       response.

       This is due to the nature of the WebSocket protocol in which just
       the WebSocket client can establish a connection with the WebSocket
       server.  Typically a WebSocket client does not listen for inbound
       connections and WebSocket servers do not open outbound
       connections.

The last paragraph of this section confuses the limitation of the 
WebSocketProtocol
implemented in a Browser as a general limitation.
It is tautological saying that a WebSocket Client can act only as a client,
however in theory a UA (outside a Browser sandbox) could act as both a 
WebSocket client and WebSocket server.

As the authors have several time claimed that they want define the usage 
of SIP on top of WebSocket for the most
general scenario and not only for the Browser/JavaScript, I would invite 
to be more clear

/Salvatore

---

From: Iñaki Baz Castillo <[email-masked]>
Date: Sun, 29 Apr 2012 20:13:44 +0200

2012/4/29 Salvatore Loreto <[email-masked]>:
> As the authors have several time claimed that they want define the usage of
> SIP on top of WebSocket for the most
> general scenario and not only for the Browser/JavaScript, I would invite to
> be more clear

Very good point, the authors already discussed about that exact point
and decided to keep it for now until further discussion takes place.

IMHO you are right and the best I can suggest is just removing section
5.2.3. As you say, if a SIP UA implements a WebSocket client and
server, it has no problems in receiving responses in a new inbound WS
connection.

Thanks a lot.

-- 
Iñaki Baz Castillo
<[email-masked]>