Re: [rtcweb] Review comments on draft-ietf-rtcweb-data-protocol-03

Michael Tuexen <Michael.Tuexen@lurchi.franken.de> Tue, 04 March 2014 18:28 UTC

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From: Michael Tuexen <Michael.Tuexen@lurchi.franken.de>
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Date: Tue, 4 Mar 2014 18:28:21 +0000
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To: Paul Kyzivat <pkyzivat@alum.mit.edu>
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Subject: Re: [rtcweb] Review comments on draft-ietf-rtcweb-data-protocol-03
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On 04 Mar 2014, at 17:54, Paul Kyzivat <pkyzivat@alum.mit.edu> wrote:

> On 2/25/14 5:07 PM, Michael Tuexen wrote:
> 
>>> 2. Section 4:
>>> 
>>> The method
>>>   used to determine which side uses odd or even is based on the
>>>   underlying DTLS connection role when used in WebRTC, with the side
>>>   acting as the DTLS client using even stream identifiers.
>>> 
>>> Isn't this unnecessary using the vague word of WebRTC instead of simply
>>> pointing to the DTLS roles of the established data channel?
>> The point is that in the WebRTC you use DCEP/SCTP/DTLS/UDP and therefore
>> you can refer to the DTLS role. However, you could use DCEP/SCTP/IP
>> or DCEP/SCTP/UDP/IP or DCEP/SCTP over something not involving DTLS.
>> In that case DTLS is not used and you can not refer to the DTLS role.
>> That is why the restriction is used.
> 
> So data channels could work over SCTP/IP or SCTP/UDP/IP, but in fact can't solely because the choice of even/odd role is dependent on DTLS connection role?
When not running over DTLS, you have not the security features provided by DTLS, of course.
> 
> Couldn't you find a way to choose the even/odd role based solely on the SCTP layer and the SDP? Then data channels could be used over those other stacks.
When running over UDP or IP you could define a client and server role and use a similar rule.

Best regards
Michael
> 
> 	Thanks,
> 	Paul
> 
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