[RTW] [dispatch] Fwd: New Version Notification for draft-alvestrand-dispatch-rtcweb-protocols-00

Thu Dec 23 10:44:14 CET 2010

Hi Justin

In some sense you are very right but I make a slightly different interpretation.

Quoting section 4 in RFC3711
"While there are numerous encryption and message authentication algorithms that can be used in SRTP, below we define default algorithms in order to avoid the complexity of specifying the encodings for the signaling of algorithm and parameter identifiers. The defined algorithms have been chosen as they fulfill the goals listed in Section 2. Recommendations on how to extend SRTP with new transforms are given in Section 6."
I don't interpret this as mandatory to implement said algorithms, rather I see this as something needed to make the RFC complete. The encryption can be negotiated out of band so an implementer can avoid said algorithms completely if he/she wants to.
Now I don't say that this is _the_ interpretation, please correct me if neecessary.

I don't intend to enter a heated debate about which codecs should be used.
My concern is more that it is not good to end up in a situation where a mandatory codec is specified in an IETF RFC and later on gets subject to some legal issues. What is the situation for the RFC then?, should the codec be demoted to optional in a new RFC that deprecates the old ?
I don't have the answers, hope that some of the "grey-beards" can chime in and give some guidance later on.

Regards and happy holidays
/Ingemar

________________________________
From: Justin Uberti [mailto:juberti at google.com]
Sent: den 22 december 2010 17:15
To: Ingemar Johansson S
Cc: dispatch at ietf.org; rtc-web at alvestrand.no; Markus.Isomaki at nokia.com
Subject: Re: [RTW] [dispatch] Fwd: New Version Notification for draft-alvestrand-dispatch-rtcweb-protocols-00

Ingemar,

RFC 3711 defines AES as the default encryption algorithm and HMAC-SHA1 as the default authentication algorithm for SRTP. As a result, those algorithms are used by pretty much every application that uses SRTP, which makes interoperability much easier.

I think a similar statement can be made regarding the selection of MTI video codecs. There are various reasons why one might choose one codec versus another. But if we are unable to pick at least one default/MTI codec (for each media type), interoperability and thereby adoption of this platform will be much more challenging.

--justin

On Tue, Dec 21, 2010 at 11:44 PM, Ingemar Johansson S <ingemar.s.johansson at ericsson.com<mailto:ingemar.s.johansson at ericsson.com>> wrote:
Hi

Not meaning to express any preference in any direction but more a question to the more experiened IETFers.

My impression here is that algorithms devised outside the IETF are rarely mandated in IETF frameworks.

Two examples that I can come up with are

SRTP (RFC3711): Only specifies the framework for secure RTP but does not mandate any encryption/authentication algorithms. Not sure if excryption algos are specified in separate RFC's

FECFRAME (RFC6015): Specifies the framework for generic FEC, generic enough to plug in any FEC algo, the actual FEC algos are specified in separate drafs (http://tools.ietf.org/wg/fecframe/)
Perhaps there are similar examples in other IETF areas that can serve as guidance ?, you may want to ping the eriIetf list on this (I leave it up to you)

So to me it seems like there is preference to _not_ mandate algorithms (compression, fec, encryption) in IETF frameworks (I can imagine one specific reason to this). And... as I believe that RTC-Web will be some kind of framework I would say that this would apply here as well ?.

Please feel free to bash my conclusion.

/Ingemar

-------------------------------------------
Message: 1
Date: Tue, 21 Dec 2010 21:38:42 +0000
From: <Markus.Isomaki at nokia.com<mailto:Markus.Isomaki at nokia.com>>
Subject: Re: [dispatch] Fwd: New Version Notification   for
       draft-alvestrand-dispatch-rtcweb-protocols-00
To: <peter.musgrave at magorcorp.com<mailto:peter.musgrave at magorcorp.com>>, <harald at alvestrand.no<mailto:harald at alvestrand.no>>
Cc: rtc-web at alvestrand.no<mailto:rtc-web at alvestrand.no>, dispatch at ietf.org<mailto:dispatch at ietf.org>, ted.ietf at gmail.com<mailto:ted.ietf at gmail.com>
Message-ID:
       <DD8B10B86502AB488CB2D3DB4C546E3806DA99 at 008-AM1MPN1-003.mgdnok.nokia.com<mailto:DD8B10B86502AB488CB2D3DB4C546E3806DA99 at 008-AM1MPN1-003.mgdnok.nokia.com>>

Content-Type: text/plain; charset="us-ascii"

Hi Peter, all,

About the video codec: Are there any arguments on why VP8 would not have IPR issues? It is available as an open source implementation, but that does not mean there are no IPR against it. My understanding is that the IPR situation wrt. VP8 is still unclear and thus risky. The other issue with VP8 is, as far as I know, the lack of a clear spec out of which independent interoperable implementations can be created.

So I don't at least buy the argument that we should choose VP8 as mandatory to implement video codec because of IPR reasons.

I'm working on a separate review on Harald's drafts (thanks for putting them together) and will come back to the codec issue there in more detail, but just wanted to respond to Peter's point here.

Regards,
               Markus

From: dispatch-bounces at ietf.org<mailto:dispatch-bounces at ietf.org> [mailto:dispatch-bounces at ietf.org<mailto:dispatch-bounces at ietf.org>] On Behalf Of ext Peter Musgrave
Sent: 17 December, 2010 13:48
To: Harald Alvestrand
Cc: rtc-web at alvestrand.no<mailto:rtc-web at alvestrand.no>; dispatch at ietf.org<mailto:dispatch at ietf.org>; Ted Hardie
Subject: Re: [dispatch] Fwd: New Version Notification for draft-alvestrand-dispatch-rtcweb-protocols-00

I'd also like to echo Alan's thanks for these drafts.

The protocol doc is very clear. [If you read only one dispatch draft this Christmas, make it this one. ;-)  ]

One observation to the group. The mandatory to implement video CODEC is VP8 (presumably since it does not have IPR issues - which some other choices would have).

Regards,

Peter Musgrave

Nits
Introduction
s/veichle/vehicle/

Section 2 Para "Within each.."
s/implementaiton/implementation/

Section 4 Para1
"such as" (something missing here?)

Section 5 Para2
"There is no third mandatory to implement"
? Was there a mention of a third before. Not sure why this statement is there.

On 2010-11-10, at 6:34 AM, Harald Alvestrand wrote:

This is the overview document for the IETF-related RTC-WEB work.

-------- Original Message --------
Subject:

New Version Notification for draft-alvestrand-dispatch-rtcweb-protocols-00

Date:

Wed, 10 Nov 2010 03:31:05 -0800 (PST)

From:

IETF I-D Submission Tool <idsubmission at ietf.org<mailto:idsubmission at ietf.org>><mailto:idsubmission at ietf.org<mailto:idsubmission at ietf.org>>

To:

harald at alvestrand.no<mailto:harald at alvestrand.no><mailto:harald at alvestrand.no<mailto:harald at alvestrand.no>>

A new version of I-D, draft-alvestrand-dispatch-rtcweb-protocols-00.txt has been successfully submitted by Harald Alvestrand and posted to the IETF repository.

Filename:      draft-alvestrand-dispatch-rtcweb-protocols

Revision:      00

Title:         Overview: Real Time Protocols for Brower-based Applications

Creation_date:  2010-11-11

WG ID:         Independent Submission

Number_of_pages: 9

Abstract:

This document gives an overview of a protocol suite intended for use

with real-time applications that can be deployed in browsers - "real

time communication on the Web".

It intends to serve as a starting and coordination point to make sure

all the parts that are needed to achieve this goal are findable, and

that the parts that belong in the Internet protocol suite are fully

specified and on the right publication track.

This work is an attempt to synthesize the input of many people, but

makes no claims to fully represent the views of any of them.  All

parts of the document should be regarded as open for discussion.

The IETF Secretariat.

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