Re: [MMUSIC] I-D Action: draft-ietf-mmusic-msrp-usage-data-channel-10.txt - Comment on msrp-cema attribute

Jose M Recio <jose@ch3m4.com> Thu, 25 April 2019 11:08 UTC

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To: Christer Holmberg <christer.holmberg@ericsson.com>, RIchard Ejzak <richard.ejzak@gmail.com>, "mmusic@ietf.org" <mmusic@ietf.org>
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From: Jose M Recio <jose@ch3m4.com>
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Date: Thu, 25 Apr 2019 19:08:04 +0800
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Subject: Re: [MMUSIC] I-D Action: draft-ietf-mmusic-msrp-usage-data-channel-10.txt - Comment on msrp-cema attribute
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On 23/4/19 1:56 PM, Christer Holmberg wrote:

>>     Since I wrote the original text, I should probably reply...
>>     
>>     I agree with Christer that the CEMA attribute is not needed.  It was
>>     originally included to make it clear that the path attribute could not
>>     be used to establish the data channel.  But this is obvious for this new
>>     type of transport.  RFC7977 (WebSocket transport for MSRP) handles this
>>     very nicely by using an .invalid domain name in the path attribute.  I
>>     suggest adopting this approach for dc.

Would this be a fair summary:

- Paragraph in discussion was meant to prevent using path attribute, but that's a moot point for data channel anyway.

To make this more clear, we can: 1) remove the paragraph, adding a clarification sentence for the reader saying that, due to the nature of the transport, path is not used for dc establishment; and 2) remove all references to cema attribute.

With that, I think mandatory modification of the path is not needed, as it's clear that the address and port parts are not used for dc. It can be added as a way to make it more explicit.