[RTW] WG charter, take 4

Thu Feb 24 20:51:08 CET 2011

Agree with Jonathan on the security issues below. 

Personally, I'd like to see an analysis of the issues added to the charter
-- along with some opportunity for the
security community to review the document.   Allowing P2P media is a
non-trivial change to the security threat 
model of the browser. 

-----Original Message-----
From: rtc-web-bounces at alvestrand.no [mailto:rtc-web-bounces at alvestrand.no]
On Behalf Of Rosenberg, Jonathan
Sent: Thursday, February 24, 2011 8:33 AM
To: 'Harald Alvestrand'; RTC-Web at alvestrand.no
Subject: Re: [RTW] WG charter, take 4

A few comments:

I'm happy with the charter language around discussion of session
management protocols being in scope for the WG. I don't understand why,
during the BoF, we will discuss whether to bake a decision on this into
the charter. Determining the protocols needed for browser RTC - both the
types of protocols and specific protocol instances and profiles - is the
work of the group and NOT the work of the charter.

This piece of wording is also concerning:
>have interactive real time voice and video pairwise between browsers or
>other devices using RTP

While I think we agree this is a goal, there are real security issues in
play here that the group needs to iron out. I do not want to bake in a
charter requirement that says we MUST deliver a solution that allows
point-to-point media (i.e., no gateways or SBCs or other intermediaries)
between browsers and existing RTP endpoints. I'd suggest something softer
like:

"enable real-time voice and video communications between browsers and
non-browser endpoints, with direct media when possible based on security
and interoperability considerations"

Which states the intent but leaves the recommendation to the wg.

Thanks,
Jonathan R.

Jonathan D. Rosenberg, Ph.D.               SkypeID: jdrosen
Skype Chief Technology Strategist                               
jdrosen at skype.net                          http://www.skype.com
jdrosen at jdrosen.net                        http://www.jdrosen.net

-----Original Message-----
From: rtc-web-bounces at alvestrand.no [mailto:rtc-web-bounces at alvestrand.no]
On Behalf Of Harald Alvestrand
Sent: Thursday, February 24, 2011 8:45 AM
To: RTC-Web at alvestrand.no
Subject: [RTW] WG charter, take 4

This is the current charter text - it's updated somewhat based on
discussions on the list.

In particular, there's now suggested language about the relationship to
session management protocols.
We'll make this an explicit discussion at the BOF, with the aim of
getting one of three conclusions in the charter:

- The WG will not address session management protocols
- The WG will choose one or more session management protocols
- The WG will discuss session management protocols, and do what makes
sense.

The last one is the one suggested by the current charter text; the other
possible outcomes should be easier to write text for.

Comments welcome!

Harald

(Note: The below is not going out in < 80 columns, I think. Please
forgive the formatting issue.)

------------------------------------------------

Version: 4

Name: RTCWEB
WG Chair(s): Cullen Jennings <fluffy at cisco.com>

Body:

Many implementations have been made that use a Web browser to support
direct, interactive communications, including voice, video,
collaboration, and gaming. In these implementations, the web server acts
as the signaling path between these applications, using locally
significant identifiers to set up the association. Up till now, such
applications have typically required the installation of plugins or
non-standard browser extensions. There is a desire to standardize this
functionality, so that this type of application can be run in any
compatible browser and allow for high-quality real-time communications
experiences within the browser.

Traditionally, the W3C has defined API and markup languages such as HTML
that work in conjunction with with the IETF over the wire protocols such
as HTTP to allow web browsers to display media that does not have real
time interactive constraints with another human.

The W3C and IETF plan to collaborate together in their traditional way
to meet the evolving needs of browsers. Specifically the IETF will
provide a set of on the wire protocols, including RTP, to meet the needs
on interactive communications, and the W3C will define the API and
markup to allow web application developers to control the on the wire
protocols. This will allow application developers to write applications
that run in a browser and facilitate interactive communications between
users for voice and video communications, collaboration, and gaming.

This working group will select and define a minimal set of protocols
that will enable browsers to:
have interactive real time voice and video pairwise between browsers or
other devices using RTP
have interactive real time application data for collaboration and gaming
pairwise between browsers

Fortunately very little development of new protocol at IETF is required
for this, only selection of existing protocols and selection of minimum
capabilities to ensure interoperability. The following protocols are
candidates for including in the profile set:

1) RTP/ RTCP

2) a baseline audio codec for high quality interactive audio. Opus will
be one of the codecs considered

3) a baseline audio codec for PSTN interoperability. G.711 and iLBC will
be some of the codecs considered

4) a baseline video codec. H.264 and VP8 will be some of the codecs
considered

5) Diffserv based QoS

6) NAT traversal using ICE

7) media based DTMF

8) support for identifying streams’ purpose using semantics labels
mappable to the labels described in RFC 4574

9) Secure RTP and keying

10) support for IPv4, IPv6 and dual stack browsers

Please note the above list is only a set of candidates that the WG may
consider and is not list of things that will be in the profile the set.

This group's primary aim is to enable web applications to manage
real-time communication sessions with other web-context applications
that implement this specification. When making choices, the working
group will also consider the impact of those choices on interoperability
with other devices that create or manage multimedia sessions, including
the complexity imposed
on any gateways which may be required.

The Working group will identify information needed for session
negotiation and management in web contexts, and its output documents
will describe the relationship of this to information carried in session
protocols used in other standardized contexts.

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 cooperate closely with the W3C activity that
specifies a semantic level API that allows the control and manipulation
of all the functionality above. In addition, the API needs to
communicate state information and events about what is happening in the
browser to applications running in the browser. These events and state
need to include information such as: receiving DTMF in the RTP, RTP and
RTCP statistics, and the state of DTLS/SRTP handshakes. The output of
this WG will form input to the W3C group that specifies the API, and if
there are parts of the mapping between the API and the protocols that
need to be done outside of the W3C, this group will do it.

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.

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, LOST,
Geolocation, IM & Presence, NSIS, Resource Priority. RTP Payload formats
will not be done in this WG.

Deliverables:
An overview document describing the architecture
A scenarios document describing scenarios that are expected to be
supported
A profile document specifying the protocols and options that must be
supported by a conforming implementation
(If needed) A mapping document describing the relationship between the
protocols and the W3C-defined API.

Milestones:

May 2011 Main alternatives identified in drafts

Aug 2011 WG draft with text reflecting agreement of what the profile set
should be

Sept 2011 Scenarios specification to IESG as Informational

Nov 2011 Draft available of documentation specifying mapping of protocol
functionality to W3C-specified API produced. This is an input to W3C API
work.

Dec 2011 Profile specification to IESG as PS

Apr 2012 Mapping document submitted to the IESG as Informational (if
needed)

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