OK, so what I think Christer and Andy are saying is that it is not just about having the right the mandatory-to-implement protocols, codecs, etc., but also about sufficient control at the API so that appropriate ones can be selected when interoperating with existing equipment. I would agree with that. Do Christer and Andy consider my text proposal for the charter to be sufficient, or does it need changing or extending? John
-----Original Message----- From: Hutton, Andrew Sent: 21 March 2011 14:16 To: Elwell, John; Christer Holmberg; Ted Hardie Cc: rtc-web@alvestrand.no Subject: RE: [RTW] New proposed charter text. Please review before the BoF.
Hi,
I think Christer's comment is really important.
If the web application is going to be responsible for ensuring interoperability with SIP or anything else then the API between the browser and the web application needs to be flexible and powerful to enable this interoperability to take place. So I believe the charter needs to make it clear that the input for this API that the IETF provides to W3C will take in to account the fact that the web application has to achieve interoperability with non RTC-Web based systems of which SIP/SDP based systems are the obvious example.
Regards Andy
-----Original Message----- From: rtc-web-bounces@alvestrand.no [mailto:rtc-web-bounces@alvestrand.no] On Behalf Of Elwell, John Sent: 21 March 2011 07:41 To: Christer Holmberg; Ted Hardie Cc: rtc-web@alvestrand.no Subject: Re: [RTW] New proposed charter text. Please review before the BoF.
-----Original Message----- From: Christer Holmberg [mailto:christer.holmberg@ericsson.com] Sent: 19 March 2011 11:22 To: Ted Hardie; Elwell, John Cc: rtc-web@alvestrand.no Subject: RE: [RTW] New proposed charter text. Please review before the BoF.
Hi,
Regarding interoperability (or, creating new solutions in general), there are a couple of things we need to consider.
One is of course the protocols supported by the browser (e.g RTP, ICE etc).
The second, which I THINK John is referring to, is to ensure that web applications (whether they are SIP based or based on something else) are able to ENABLE the browser protocols and features in a good and effective way. For that we need to ensure that the API between the browser and the web app is powerful enough. [JRE] That might be one of the consequences - if the browser is able to use a protocol that is not interoperable with existing equipment and a protocol that is interoperable, then clearly an application wanting to interoperate would want to be able to choose the latter.
That was not the main point of my proposed addition to the charter - the main point was that the set of mandatory-to-implement protocols in the browser should include those that can interoperate in a reasonable way with existing equipment. Based on discussions to date, the most problematic is likely to be codecs, particularly video codecs, because of the cost and performance degradation when transcoding has to be done.
John
In the ucreqs document, we have tried to differentiate between those two things by having separate browser requirements and API requirements.
Regards,
Christer
________________________________________ From: rtc-web-bounces@alvestrand.no [rtc-web-bounces@alvestrand.no] On Behalf Of Ted Hardie [ted.ietf@gmail.com] Sent: Friday, March 18, 2011 7:38 PM To: Elwell, John Cc: rtc-web@alvestrand.no Subject: Re: [RTW] New proposed charter text. Please review before the BoF.
On Fri, Mar 18, 2011 at 10:17 AM, Elwell, John <john.elwell@siemens-enterprise.com> wrote:
Ted,
In the same way that charters tend to call out "horizontal" topics for special mention, such as security, privacy and NAT/firewall, I believe the ability to achieve interop with existing equipment should also be given a mention.
Hi John,
Unsurprisingly, I am also a fan of interoperability. But I think there are multiple ways to scope interoperability. The charter currently does it by focusing on the interoperability we
get at the
protocol level, largely by choosing tools for this toolkit that match the tools already in place (e.g. RTP, ICE, etc.). I agree that we shouldn't select tools that are in place but unusable. I think we end up having to trust the working group on this anyway, as it will decide which tools are unusuable even if we insert a "don't pick unusable tools" section.
So the basic question boils down to: do we also want to assert a need for interoperability with a specific application or set of applications in the charter?
My personal take is no. Those are use cases, and important ones. But the charter is focused on building a toolkit "to enable innovation on top of a set of basic components." I have no doubt that someone will be able to build a fully backwards compatible service using these components and a gateway,. But the more important charter goal is to get the component set right to enable them to build more than that. And I think calling out that specific use case is more likely to limit our vision than to result in more clarity in picking protocols and tools.
Again, just my personal opinion,
regards,
Ted Hardie
Note that I stop short of demanding backwards compatibility, but instead make a somewhat more flexible proposal.
Using defined protocols isn't necessarily sufficient if we pick things that are not implemented. As an extreme case, take S/MIME, for example.
John
-----Original Message----- From: Ted Hardie [mailto:ted.ietf@gmail.com] Sent: 18 March 2011 17:01 To: Elwell, John Cc: rtc-web@alvestrand.no Subject: Re: [RTW] New proposed charter text. Please review before the BoF.
On Fri, Mar 18, 2011 at 5:04 AM, Elwell, John <john.elwell@siemens-enterprise.com> wrote:
Ted,
I think there needs to be some mention of interop with existing real-time applications using IETF protocols (such as SIP, RTP). Something along the lines of: "Work should take account of browser-based applications that require to interoperate with existing applications using IETF protocols such as SIP and RTP and commonly deployed audio and video codecs. Solutions that require mediation functions to achieve interoperation might be acceptable, provided such functions are not unduly complex, expensive or detrimental to performance."
So, my personal read is that these work items:
"4. Define which RTP functions and extensions shall be supported in the client and their usage for real-time media, including media adaptation to ensure congestion safe usage. 5. Define what functionalities in the solution, such as media codecs, security algorithms, etc., can be extended and how the extensibility mechanisms works. 6. Define a set of media formats that must or should be supported by a client to improve interoperability."
and this general statement which follows the work items:
"This work will be done primarily by using already defined protocols or functionalities. "
Those seem to cover the same ground as your "take account of". If your aim is to get to something more concrete, like "you must be able to build a browser-based SIP softphone using the tools identified by this group", I think you need to unpack that a bit more. Some of the presence aspects of that toolkit, for example, may not be identified here.
To put this another way, my personal read is that we're aiming to create the toolkit needed to build real-time media applications in web contexts. Any specific application, including a SIP softphone, would be a use of the toolkit; those will be covered by something like draft-holmberg-rtcweb-ucreqs-00.txt as a use case, rather than in the charter.
Again, just my personal take on this.
regards,
Ted Hardie
John
> -----Original Message----- > From: rtc-web-bounces@alvestrand.no > [mailto:rtc-web-bounces@alvestrand.no] On Behalf Of Ted Hardie > Sent: 17 March 2011 16:18 > To: rtc-web@alvestrand.no > Subject: [RTW] New proposed charter text. Please review > before the BoF. > > Name: Real-Time Communication in WEB-browsers (RTCWeb) > > There are a number of proprietary implementations that provide direct > interactive rich communication using audio, video, collaboration, > games, etc. between two peers' web-browsers. These are not > interoperable, as they require non-standard extensions or plugins to > work. There is a desire to standardize the basis for such > communication so that interoperable communication can be established > between any compatible browsers. The goal is to enable innovation on > top of a set of basic components. One core component is to enable > real-time media like audio and video, a second is to enable datagram > and byte stream data transfer directly between clients. > > This work will be done in collaboration with the W3C. The IETF WG > will produce architecture and requirements for selection and profiling > of the on the wire protocols. The architecture needs to be coordinated > with W3C. The IETF WG work will identity state information and events > that need to be exposed in the APIs as input to W3C. The W3C will be > responsible for defining APIs to ensure that application developers > can control the components. > > The security goals and requirements will be developed by the WG. The > security model needs to be coordinated with the W3C. The work will > also consider where support for extensibility is needed. RTP > functionalities, media formats, security algorithms are example of > things that commonly needs extensions, additions or replacement, and > thus some support for negotiation between clients is required. > > The WG will perform the following work: > 1. Define the communication model in detail, including how session > management is to occur within the model. > 2. Define a security model that describes the security goals and > how the communication model can achieve these goals. > 3. Define how NAT and Firewall traversal is to occur. > 4. Define which RTP functions and extensions that shall be > supported in the client and their usage for real-time media, including > media adaptation to ensure congestion safe usage. > 5. Define what functionalities in the solution, such as media > codecs, security algorithms, etc., that can be extended and how the > extensibility mechanisms works. > 6. Define a set of media formats that must or should be supported > by a client to improve interoperability. > 7. Define how non RTP datagram and byte stream data communication > between the clients can be done securely and in a congestion safe way. > 8. Provide W3C input for the APIs that comes from the > communication model and the selected components and protocols that are > part of the solution. > > > This work will be done primarily by using already defined protocols or > functionalities. If there is identification of missing protocols or > functionalities, such work can be requested to be done in another > working group with a suitable charter or by requests for chartering it > in this WG or another WG. The following topics will be out of scope > for the initial phase of the WG but could be added after a recharter: > RTSP, RSVP, NSIS, Location services, IM & Presence, Resource Priority. > > The products of the working group will support security and keying as > required by BCP 61 and be defined for IPv4, IPv6, and dual stack > deployments. The Working Group will consider the possibility of > defining a browser component that implements an existing session > negotiation and management protocol. The working group will follow BCP > 79, and adhere to the spirit of BCP 79. The working group cannot > explicitly rule out the possibility of adopting encumbered > technologies; however, the working group will try to avoid encumbered > technologies that require royalties or other encumbrances that would > prevent such technologies from being easy to use in web browsers. > > Milestones: > > Aug 2011 Architecture and Security and Threat Model sent to W3C > > Aug 2011 Use cases and Scenarios document sent to W3C > > Sept 2011 Architecture and Security and Threat Model to IESG > as Informational > > Sept 2011 Use cases and Scenarios for RTCWeb document sent to IESG as > Informational > > Dec 2011 RTCWeb and Media format specification(s) to IESG as PS > > Dec 2011 Information elements and events APIs Input to W3C > > Apr 2012 API to Protocol mapping document submitted to the IESG as > Informational (if needed) > _______________________________________________ > RTC-Web mailing list > RTC-Web@alvestrand.no > http://www.alvestrand.no/mailman/listinfo/rtc-web >
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