Re: [MMUSIC] Merging ICE aggressive and regular nomination (was Re: [tram] Comment on draft-williams-peer-redirect-01: might it not converge?)

Iñaki Baz Castillo <ibc@aliax.net> Sat, 02 August 2014 22:06 UTC

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From: Iñaki Baz Castillo <ibc@aliax.net>
Date: Sun, 03 Aug 2014 00:06:26 +0200
Message-ID: <CALiegfnn0Vs-TeTn29fhC4Hb9RFVZOAzx7ZQHRCVBDp=VF+ObQ@mail.gmail.com>
To: Martin Thomson <martin.thomson@gmail.com>
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Cc: Jonathan Lennox <jonathan@vidyo.com>, mmusic <mmusic@ietf.org>
Subject: Re: [MMUSIC] Merging ICE aggressive and regular nomination (was Re: [tram] Comment on draft-williams-peer-redirect-01: might it not converge?)
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2014-08-01 18:04 GMT+02:00 Martin Thomson <martin.thomson@gmail.com>:
> On 1 August 2014 01:15, Iñaki Baz Castillo <ibc@aliax.net> wrote:
>> PS: In the text above I'm assuming that peerA initiates two different
>> DTLS handshakes over pair1 and pair2. In case bullet 2) is the way to
>> go, may we assume/mandate at least that peerA MUST perform a *single*
>> DTLS handshake (regardless packets are sent and received via pair1 or
>> pair2 or via both of them)?
>
> You can only have one DTLS connection, however...
>
> Sending two ClientHellos is OK, because DTLS requires retransmission
> of ClientHello to deal with packet loss.  The server should treat
> those as duplicates (and if they don't carry the same information, you
> are setting yourself up for failure when it comes to generating the
> Finished message).

OK, that's clear. If a single DTLS handshake is allowed then things
become easier.

Just a question: how to determine the remote address for sending data?
Theoretically that is determined by the "selected ICE pair", but what
about if, at some point, the remote peer sends a valid SRTP packet
from a different address (let's imagine it is an address from which a
valid ICE Binding request with USE-CANDIDATE was previously received
assuming the remote peer uses aggressive nomination)?. Should the
local peer change its sending address?

-- 
Iñaki Baz Castillo
<ibc@aliax.net>