Subject: [rtcweb] Is "use_srtp" DTLS extension required if just DataChannel is requested?

From: Iñaki Baz Castillo <[email-masked]>
Date: Tue, 5 Jan 2016 20:55:49 +0100

If a WebRTC endpoint acting as DTLS client just wants to offer a
DataChannel (and not audio or video) should it also include the
"use_srtp" DTLS extension?

Should a WebRTC endpoint acting as DTLS server reject the DTLS
handshake if the DTLS client did not include the "use_srtp" DTLS
extension?

Thanks.

-- 
Iñaki Baz Castillo
<[email-masked]>

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From: Roman Shpount <[email-masked]>
Date: Tue, 5 Jan 2016 16:36:25 -0500

I think the decision was that "use_srtp" DTLS extension is required and
DTLS server should reject the handshake if this extension is not offered.
This was decided since it is difficult to predict if RTP would be added in
the bundle over the same transport in some point in the future.
Without "use_srtp"
DTLS extension being present from the start adding RTP would require
negotiating a whole new transport including ICE setup since "use_srtp"
extension cannot be added to an existing DTLS association.

_____________
Roman Shpount

On Tue, Jan 5, 2016 at 2:55 PM, Iñaki Baz Castillo <[email-masked]> wrote:

> _______________________________________________
> rtcweb mailing list
> [email-masked]
> https://www.ietf.org/mailman/listinfo/rtcweb
>

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From: Iñaki Baz Castillo <[email-masked]>
Date: Tue, 5 Jan 2016 22:37:16 +0100

2016-01-05 22:36 GMT+01:00 Roman Shpount <[email-masked]>:
> I think the decision was that "use_srtp" DTLS extension is required and DTLS
> server should reject the handshake if this extension is not offered. This
> was decided since it is difficult to predict if RTP would be added in the
> bundle over the same transport in some point in the future. Without
> "use_srtp" DTLS extension being present from the start adding RTP would
> require negotiating a whole new transport including ICE setup since
> "use_srtp" extension cannot be added to an existing DTLS association.

Clear. Thanks.

-- 
Iñaki Baz Castillo
<[email-masked]>