Re: [MMUSIC] I-D Action: draft-ietf-mmusic-msrp-usage-data-channel-11.txt

[Christer Holmberg <[e-mail]>]

Hi,

>>>> But, are the data channel endpoints still going to insert the path(s) in the MSRP messages?
>>>>
>>>> I think nothing prevents endpoints to format From-Path and To-Path in
>>>> MSRP messages as required by the application, for example, as defined by
>>>> RCS specifications.
>>  
>> Sure, but this draft needs to define what the endpoints do.
>
>    The draft does not need to impose any requirements on how the endpoints 
>    form the MSRP messages. This is defined by the MSRP RFCs, RCS specs, or 
>    others.
  
You may be right. In the non-gateway case I think the only important thing to point out is the usage of CEMA (see other e-mail).

---
  
>>> If the other endpoint is not a GW or is a GW acting as B2BUA, those
>>> fields would be processed as defined by MSRP and the application using
>>> the protocol.
>>>
>>> If the other endpoint is a GW providing transport interworking, there's
>>> no reason for look at MSRP messages. It should be restricted to
>>> transport interworking. How transport is established it's not defined by
>>> the draft, it just says that path attributes should not be used for that
>>> purpose.
>>      
>>  Let's forget GWs for a moment, and focus on the data channel. A data channel endpoint does not know whether the peer is a GW, so there needs to be generic procedures.
>
>  What I tried to explain (unsuccesfully) is that MSRP processing is not 
>  affected in endpoints implementing this draft, it is the same if the 
>  endpoint is either a gateway or another endpoint.

I agree with that: an MSRP data channel endpoint doesn't need to know whether the peer is an endpoint or a gateway.

---    
    
>>      We need text that describes how the MSRP messages are created/encoded. We can simply 
>>      refer to 4975 if that works, but it needs to be clear whether to e.g., use
>>      received path attributes and create To/From-paths etc.
>    I agree with that, I think referring back to 4975 is enough, and it would make  behavior more clear.

Yes. I was thinking whether we need to reference CEMA e.g., for URI comparison, but probably not.

I will keep discussions related to gateway in a separate e-mail.

Regards,

Christer