Last Call Review of draft-ietf-mmusic-msrp-usage-data-channel-23
review-ietf-mmusic-msrp-usage-data-channel-23-tsvart-lc-nishida-2020-08-12-00

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ongoing effort to review key IETF documents. These comments were written
primarily for the transport area directors, but are copied to the document's
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Summary: This document is almost ready for publication, but I think it will be
better to clarify the following points.

1: If the other endpoints is on a TCP connection, It seems to me that it can
look downgrading the security level of the connection.
   If this is the case, do we need some guidances here?

2: 'If the non-data channel endpoint does not support MSRP CEMA, transport
level interworking mode is not possible,
   it needs to act as an MSRP B2BUA.'
   -> This may sound like it falls back to B2BUA when CEMA is not available.
        But, I guess there might be a case where users don't want fallback.

3: As the doc mentions the use of B2BUA, it might be useful to refer security
consideration in RFC7092 in Section 9.