Re: [MMUSIC] WGLC on draft-ietf-mmusic-msrp-usage-data-channel-16

[Paul Kyzivat <[e-mail]>]

On 5/12/20 8:32 AM, Christer Holmberg wrote:
> Hi,
> 
>>- Added text to make more clear the scope of path and MSRP URI:
> 
>>Data channels are negotiated independently of the value of the "path" 
> attribute. This means that when MSRP messages are transported on a data 
> channel, the "path" attribute
> 
>>is not used for transport negotiation or routing of the messages. MSRP 
> endpoints using data channels can set the value of the "path" attribute, 
> including the MSRP URI, and use it as described in RFC4975
> 
> I think we need to be a little more explicit, so I suggest something like:
> 
> "When MSRP messages are transported on a data channel, the "path" 
> attribute is not used for routing of the messages. The MSRP data channel 
> is established using the SDP offer/answer procedures defined in 
> [I-D.ietf-rtcweb-data-channel], and the MSRP messages are then 
> transported on that data channel. Because of that an MSRP endpoint can 
> set the MSRP-URI authority value of the "path" attribute at its own 
> discretion, following the syntax and rules in [RFC4975]."

I'm concerned that this might imply that an msrp(s) URI is not 
sufficient information to establish communication. (That some additional 
information, received out-of-band, might be a prerequisite.)

Do you intend that to be a possible situation?

I would hope that it is not - that an msrp(s) URI is sufficient. In that 
case, both the transport setup and the path attribute would be derived 
from the same source.

	Thanks,
	Paul