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</o:shapelayout></xml><![endif]--></head><body lang=EN-US link=blue vlink=purple><div class=WordSection1><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>One approach is to tunnel the signaling protocol over HTTP. This requires support for bi-directional communications, such as can be provided by BOSH, or Websockets. In these architectures the web client communicates via HTTP with a “Connection Manager” which encapsulates/decapsulates the signaling messages and routes them appropriately on the backend. <o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>To provide interoperability, specifications for encapsulation of signaling messages within HTTP are required. Examples include:<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><a href="http://xmpp.org/extensions/xep-0124.html">XEP-0124</a>: Bidirectional-streams Over Synchronous HTTP (BOSH)<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><a href="http://xmpp.org/extensions/xep-0206.html">XEP-0206</a>: XMPP over BOSH<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><a href="http://tools.ietf.org/html/draft-moffitt-xmpp-over-websocket">An XMPP Sub-protocol for Websocket</a><o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>Information on BOSH implementations can be found here:<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><a href="http://xmpp.org/about-xmpp/technology-overview/bosh/#impl">http://xmpp.org/about-xmpp/technology-overview/bosh/#impl</a><o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><o:p> </o:p></span></p><div><div style='border:none;border-top:solid #B5C4DF 1.0pt;padding:3.0pt 0in 0in 0in'><p class=MsoNormal><b><span style='font-size:10.0pt;font-family:"Tahoma","sans-serif"'>From:</span></b><span style='font-size:10.0pt;font-family:"Tahoma","sans-serif"'> rtc-web-bounces@alvestrand.no [mailto:rtc-web-bounces@alvestrand.no] <b>On Behalf Of </b>Markus.Isomaki@nokia.com<br><b>Sent:</b> Sunday, January 30, 2011 2:45 PM<br><b>To:</b> bernard_aboba@hotmail.com; richard@shockey.us; erik@hookflash.com; jonathan.rosenberg@skype.net<br><b>Cc:</b> rtc-web@alvestrand.no; dispatch@ietf.org<br><b>Subject:</b> Re: [RTW] [dispatch] Does RTC-WEB need to pick a signaling protocol?<o:p></o:p></span></p></div></div><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>Hi,<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>I pretty much agree with what Bernard and Johathan Rosenberg have said.<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>There are just a couple of issues I would like to understand better:<o:p></o:p></span></p><p class=MsoListParagraph style='margin-left:.75in;text-indent:-.25in;mso-list:l0 level1 lfo2'><![if !supportLists]><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><span style='mso-list:Ignore'>-<span style='font:7.0pt "Times New Roman"'> </span></span></span><![endif]><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>I suppose these Javascript libraries can be cached on the browser and need not be downloaded every time the application/site is accessed? (These are probably a common practices in Javascript and Browsers but are good to clarify in this discussion.)<o:p></o:p></span></p><p class=MsoListParagraph style='margin-left:.75in;text-indent:-.25in;mso-list:l0 level1 lfo2'><![if !supportLists]><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><span style='mso-list:Ignore'>-<span style='font:7.0pt "Times New Roman"'> </span></span></span><![endif]><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>It may be easy for a web developer to use the client side Javascript library, but I believe the challenge may be bigger on the server side, where scalability etc. become issues. How about the server side, is there something ready-made for that? I suppose the Javascript on the browser can’t necessarily connect to vanilla SIP or XMPP servers but some HTTP/WebSocket/TLS tunneling and connection management magic is needed, especially when dealing with HTTP intermediaries. (But presumably the same issues would be faced if we “picked” SIP or XMPP.)<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>Markus<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><o:p> </o:p></span></p><div style='border:none;border-left:solid blue 1.5pt;padding:0in 0in 0in 4.0pt'><div><div style='border:none;border-top:solid #B5C4DF 1.0pt;padding:3.0pt 0in 0in 0in'><p class=MsoNormal><b><span style='font-size:10.0pt;font-family:"Tahoma","sans-serif"'>From:</span></b><span style='font-size:10.0pt;font-family:"Tahoma","sans-serif"'> rtc-web-bounces@alvestrand.no [mailto:rtc-web-bounces@alvestrand.no] <b>On Behalf Of </b>ext Bernard Aboba<br><b>Sent:</b> 30 January, 2011 07:35<br><b>To:</b> Richard Shockey; erik@hookflash.com; jonathan.rosenberg@skype.net<br><b>Cc:</b> rtc-web@alvestrand.no; dispatch@ietf.org<br><b>Subject:</b> Re: [RTW] [dispatch] Does RTC-WEB need to pick a signaling protocol?<o:p></o:p></span></p></div></div><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal style='margin-bottom:12.0pt'><span style='font-size:10.0pt;font-family:"Tahoma","sans-serif"'>> Duh ... what are we abandoning 10 years of work?<br><br>The web is a "generative" platform that supports not just protocols, but also execution of code. This enables the platform to be extended in a virtually infinite number of ways, including the development of Javascript signaling APIs, without needing to add yet more core code to the browser. This is the preferred approach unless it can be shown that something *absolutely* must be natively supported (as was discussed at the workshop, STUN/TURN authorization for peer-to-peer media is probably an example of something that *does* need to be native). <br><br>As an example of what is possible, there is an excellent Javascript library for XMPP (strophe, see <a href="http://code.stanziq.com/strophe/">http://code.stanziq.com/strophe/</a>). Poking around, it would appear that there are a number of Javascript libraries that claim to provide support for SIP (such as <a href="http://phono.com/">http://phono.com/</a>), although I have no idea of their usefulness. <br><br>Given the generality and power of the web platform and the ease with which sophisticated signaling libraries can be implemented today, the bar for getting additional code into any browser is going to be quite high. If you doubt this, ask the build-master of your favorite browser for the requirements for checkin of a complete SIP stack :) <o:p></o:p></span></p></div></div></body></html>