Re: [rtcweb] DTLS, DTLS-SRTP, and 5-tuples

[Roman Shpount <[e-mail]>]

On Thu, Mar 5, 2015 at 8:44 AM, Christer Holmberg <
[e-mail]> wrote:

> >- A sends USE-CANDIDATE requests in parallel.
> >- A receives the ok response from one of them.
> >- A sends DTLS ClientHello.
> >- A receives the ok response with higher priority from another pair.
> >- A then continues sending media (maybe remaining DTLS stuff or RTP) for
> that pair.
>
> Just to clarify: when you say "continues sending", you are NOT saying that
> A "starts over" by sending a new initial ClientHello on the new pair -
> instead A only switches to the other pair and continues with normal DTLS
> setup procedures?
>
> ...which means that both the client and server may receive DTLS messages,
> associated with the same DTLS connection setup, on different 5-tuples?
>

End point should not "start over". End point should continue the normal
DTLS setup over a new pair. This does mean that the same DTLS association
can go over different 5-tuples over time. With some of the new proposals,
such as continuous nomination, DTLS association can be switching the
underlying 5-tuple at any time while the connection is active, not just
during the initial setup. As far as DTLS is concerned, all 5-tuples setup
with the same ICE ufrag pair are the same transport and all the packets
received over any of those 5-tuples should be processed by the same DTLS
association.
_____________
Roman Shpount