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Re: [rtcweb] Data Channel Protocol: Data before DATA_CHANNEL_ACK

Peter Thatcher <pthatcher@google.com> Mon, 10 February 2014 18:21 UTC

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From: Peter Thatcher <pthatcher@google.com>
Date: Mon, 10 Feb 2014 10:20:52 -0800
Message-ID: <CAJrXDUHBBt6L7tp4Ck426xQEkAQEmOnscmu2mBFUGR8YVHqoaw@mail.gmail.com>
To: Christer Holmberg <christer.holmberg@ericsson.com>
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Cc: "rtcweb@ietf.org" <rtcweb@ietf.org>
Subject: Re: [rtcweb] Data Channel Protocol: Data before DATA_CHANNEL_ACK
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If you have to wait for the ACK, it's one more RTT you have to wait before
you can send data.  We've already got many RTTs form ICE and DTLS and
what's built into SCTP.  We originally didn't have an ACK message at all,
in large part because we didn't want more RTTs.  The ACK was put in to
handle the edge case of unordered data arriving before the OPEN message.
 But we added it in a way that it doesn't add more RTTs.


On Mon, Feb 10, 2014 at 2:20 AM, Christer Holmberg <
christer.holmberg@ericsson.com> wrote:

> Hi,
>
> As is defined in the data channel protocol, an entity can send data once
> DATA_CHANNEL_OPEN has been sent, before the associated DATA_CHANNEL_ACK is
> received.
>
> What is the reason for allowing data to be sent before DATA_CHANNEL_ACK?
> The sender may not even know (depends on whatever external negotiation
> mechanisms are used) whether the remote peer supports the protocol to begin
> with.
>
> It think it would be good to allow the remote peer to accept
> (DATA_CHANNEL_ACK) or reject (stream reset) the DATA_CHANNEL_OPEN before
> data is sent.
>
> Regards,
>
> Christer
>
>
> _______________________________________________
> rtcweb mailing list
> rtcweb@ietf.org
> https://www.ietf.org/mailman/listinfo/rtcweb
>

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