Re: [MMUSIC] Mirja Kühlewind's Discuss on draft-ietf-mmusic-sctp-sdp-23: (with DISCUSS)

Eric Rescorla <ekr@rtfm.com> Thu, 16 February 2017 15:03 UTC

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From: Eric Rescorla <ekr@rtfm.com>
Date: Thu, 16 Feb 2017 07:02:36 -0800
Message-ID: <CABcZeBPPFUe-ZtW9Lt636OhoMH8ws2oVi94YQJeUQKXteC-XRg@mail.gmail.com>
To: Christer Holmberg <christer.holmberg@ericsson.com>
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Cc: "mmusic-chairs@ietf.org" <mmusic-chairs@ietf.org>, "mmusic@ietf.org" <mmusic@ietf.org>, "fandreas@cisco.com" <fandreas@cisco.com>, "Mirja Kuehlewind \(IETF\)" <ietf@kuehlewind.net>, The IESG <iesg@ietf.org>, "draft-ietf-mmusic-sctp-sdp@ietf.org" <draft-ietf-mmusic-sctp-sdp@ietf.org>
Subject: Re: [MMUSIC] =?utf-8?q?Mirja_K=C3=BChlewind=27s_Discuss_on_draft-ietf?= =?utf-8?q?-mmusic-sctp-sdp-23=3A_=28with_DISCUSS=29?=
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As Christer says. This design is optimized for making the media stack
simpler, which
using TLS here would not do.

-Ekr




On Thu, Feb 16, 2017 at 7:00 AM, Christer Holmberg <
christer.holmberg@ericsson.com> wrote:

> Hi,
>
> ----------------------------------------------------------------------
> DISCUSS:
> ----------------------------------------------------------------------
>
> >>> Why is this using TCP/DTLS/SCTP instead of TCP/TLS/SCTP?
> >>>
> >> Because the way it is realized is by transporting SCTP on top of DTLS
> (as defined in draft-ietf-tsvwg-sctp-dtls-encaps) and
> >> transporting DTLS on top of TCP (defined in RFC 4571).
> >
> > I got this but DTLS is a mapping to use TLS with UDP because UDP is an
> unreliable datagram transport. If you use TCP, you
> > should use TLS. And rfc4571 is not a mapping of DTLS to TCP.
>
> The framing mechanism of RFC 4571 is used, with DTLS packets sent instead
> of RTP packets.
>
> Regards,
>
> Christer
>
>