Re: [MMUSIC] DTLS-over-SCTP, anyone?

[Roman Shpount <[e-mail]>]

On Wed, Feb 10, 2016 at 2:58 PM, Christer Holmberg <
[e-mail]> wrote:

> >>> I think we can add the following to section 7.1 of dtls-sdp:
> >>>
> >>> If DTLS is transmitted over a reliable transport and if DTLS
> procedures for retransmissions are not used, for instance as described in
> >>> RFC 6083 for DTLS over SCTP, then DTLS association MUST NOT span
> across multiple transports. Using 'dtls-connection' attribute with
> >>> an 'existing' value in combination with change of such a reliable
> transport should be treated as an error and DTLS association MUST be
> >>> terminated.
> >>
> >> Your text as such looks ok. But, do we really want to add it as a
> generic restriction in draft-dtls-sdp? Shouldn't it be
> >> specific for DTLS-over-SCTP instead? What if someone defines
> DTLS-over-<new-fancy-reliable-transport> and they DO allow span?
> >
> > The reason multiple DTLS associations cannot span across several SCTP
> association is due to SCTP association handling DTLS packet
> > retransmission and DTLS procedures for retransmissions not being used.
> We can make a generic statement or limit this to RFC 6083
> > only, but I think, stating the reason why DTLS association cannot span
> multiple transports is important.
>
> I agree.
>
> But, again DTLS-over-SCTP is described in draft-sctp-sdp, so I think such
> text belongs there.
>
>
How about saying the following in draft-dtls-sdp:

If DTLS is transmitted over a transport that prohibits spanning of DTLS
association across multiple transports, such as DTLS over SCTP as described
in RFC 6083, then 'dtls-connection' attribute MUST be set to 'new' every
time transport is changed.

And you can put the previous language in draft-sctp-sdp

This way each draft only specified things relevant to itself.

Regards,
_____________
Roman Shpount