Re: [Stox] Extended WGLC for draft-ietf-stox-groupchat-04 [was: WGLC for draft-ietf-stox-groupchat-04]

Hi, 

Here's some belated comments:

General:

I strongly suggest this be reviewed by one or both of the authors of draft-ietf-simple-chat, if it hasn't been already.

Conceptually it looks good. But I see some issues with the SIP interaction. It may be that I am confused by the two-gateway model, but you have a number of transactions where the SIP responses do not go back to the same entity that sent the SIP request. I suspect the intent was that one gateway or the other would handle things depending on which side initiated communication, but you've got dialogs (even individual transactions) split across them. If this is intended, then they would need to share SIP dialog and transaction state somehow.

Details:

-- Section 4: 

It would be helpful to show a network diagram before jumping directly into the call flows.  (Same for the later scenario where the conference is an XMPP MUC).

- F3 is left hanging. If the xmpp-msrp gateway sends the INVITE, it needs to receive the response and also send an ACK. Also, it appears to skip the MSRP-XMPP gateway, but the rest of the transaction terminates there.  Effectively, the MSRP-XMPP gateway receives an unsolicited SIP response. This won't work.

- F4 and F5 appear to be duplicates.

- F7 indicates the MSRP session is between the MSRP-to-XMPP gateway and the conference server. But the MSRP-XMPP gateway never saw the XMPP user enter the room. Also, there should be a initial MSRP SEND request prior to the nick.

F8: Technically, the "OK" in the MSRP response is just a comment. I suggest showing MSRP responses by just the response code in the diagram. The comment has no semantic effect (and is even optional).

F18: This assumes the MSRP default reporting model was selected. This draft should probably consider how the MSRP REPORT method fits into the picture. (Along those lines, does anything change if MSRP relays are present?)

Also, F19 needs to land on the same device that sent F18.

F20: What triggered the msrp-xmpp gateway to send the XMPP groupchat message?

-- Section 4.1, example 2:

The a=chatroom attribute does not include support for private messaging or nicknames. Since the flow uses these later, they should probably be included. (Repeats in 5.1)

-- Section 4.2, Example 6:

I suggest putting something more informative than "OK" in the MSRP 200 response. (e.g. "Nickname-Accepted").

-- Section 5:

What is the SIP Server? Is this a SIP Proxy, or something else? What value does it add to the flow? 

F46: Need an initial MSRP SEND prior to the nickname request. Also, MSRP requests should not traverse a SIP server (unless it is also an MSRP relay.)

F47: I suggest moving F47 to after F45. As is, it looks like it take the SIP server a long time to proxy the ACK.

F56 and F57:

This shows the XMPP-MSRP gateway receiving the XMPP presence message, and sending the SIP NOTIFY. But that device never saw the SIP SUBSCRIBE. Either the SUBSCRIBE should have gone to it, or F56 and F57 should have crossed the other gateway.

Thanks!

/Ben

On Apr 24, 2014, at 11:12 AM, Yana Stamcheva <yana@jitsi.org> wrote:

> Hello all,
> 
> Only one review has been received on this list during the WGLC (Thanks Philipp!) and in order to be able to proceed we would need more people to express their support for this document!
> 
> Therefore, we hereby would like to extend the WGLC period with 2 more weeks and end it on May 5, 2014.
> 
> Please, if you'd like this document to go forward, send your reviews, comments or support notes to the list before May 5, 2014!
> 
> If you're willing to review the document but for some reason you won't be able to do it before the above deadline, please contact the chairs.
> 
> Thanks!
> Yana Stamcheva & Markus Isomaki
> 
> On 06 Apr 2014, at 20:20, Yana Stamcheva <yana@jitsi.org> wrote:
> 
>> The editors and the chairs believe that the following draft is now ready and hereby start a 2-week Working Group Last Call for:
>> 
>> draft-ietf-stox-groupchat-04 : http://tools.ietf.org/html/draft-ietf-stox-groupchat-04 (Last updated on 2014-03-25)
>> 
>> The WGLC ends on April 21, 2014.
>> 
>> Please review the document and bring any remaining issues, or issues whose resolution is not satisfactory, to the attention of the Working Group on this list before April 21.
>> 
>> If after reviewing the document you find it complete and do not have any comments, please send a note to that effect as well!
>> 
>> Regards,
>> Yana Stamcheva & Markus Isomaki
> 
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