Subject: [AVT] DTLS-SRTP over TCP?

From: Eric Rescorla <[email-masked]>
Date: Mon, 25 Aug 2008 14:13:42 -0700

In his WGLC comments on draft-ietf-avt-dtls-srtp, SEC AD Pasi Erenon writes:

  Section 8 seems to specify a token DTLS over TCP. However, RFC 4347
  doesn't specify how that would work (and it's obvious that it won't
  work as is -- e.g. the state machine handling timeouts/retransmissions
  needs changes, MTU discovery won't be identical, etc.). If the intent
  is to specify DTLS-over-TCP, that really needs a separate section (or
  ideally, a separate document) describing the deltas from ordinary
  DTLS.

Pasi is right that this is underspecified. 

I know that we agreed that this would be the way forward in the future
for secure media over TCP, but what I don't know is whether this 
is imminent. My normal instinct would be to remove this from this
document and when (if?) necessary, fully specify the DTLS-SRTP 
behavior in a separate document. What do others think?

Thanks,
-Ekr

_______________________________________________
Audio/Video Transport Working Group
[email-masked]
https://www.ietf.org/mailman/listinfo/avt

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From: "Dan Wing" <[email-masked]>
Date: Mon, 25 Aug 2008 14:31:19 -0700

> behavior in a separate document. What do others think?

This primarily affects ICE-TCP, when UDP communications can't be
established and only TCP can be established.  I don't see much other
significant use of DTLS-SRTP-over-TCP.

I am okay with removing it, so long as ICE-TCP mentions that DTLS-SRTP
cannot utilize an ICE-TCP-negotiated TCP transport.

-d

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From: "Roni Even" <[email-masked]>
Date: Tue, 26 Aug 2008 07:58:48 +0300

Hi,
I think it is reasonable to remove TCP in the current draft. 
Maybe, for completeness, have some text similar to section 3 of
draft-ietf-avt-srtp-not-mandatory-00 suggesting that for TCP you can use TLS
and suggest that DTLS-SRTP-over-TCP is for further study.
Roni Even

-----Original Message-----
From: [email-masked] [mailto:[email-masked]] On Behalf Of Dan
Wing
Sent: Tuesday, August 26, 2008 12:31 AM
To: 'Eric Rescorla'; [email-masked]
Subject: Re: [AVT] DTLS-SRTP over TCP?

-d