Re: [Stox] Nickname Usage Conflict Resolution

Peter Saint-Andre <stpeter@stpeter.im> Wed, 24 July 2013 02:57 UTC

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Date: Tue, 23 Jul 2013 20:57:30 -0600
From: Peter Saint-Andre <stpeter@stpeter.im>
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Cc: "stox@ietf.org" <stox@ietf.org>, "De Vries, Michael \[USA\]" <devries_michael@bah.com>
Subject: Re: [Stox] Nickname Usage Conflict Resolution
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On 7/20/13 7:48 AM, Saúl Ibarra Corretgé wrote:
> Hi Michael,
> 
> On Jul 20, 2013, at 1:07 AM, De Vries, Michael [USA] wrote:
> 
>> Hello everyone,
>> 
>> I have a concern with the suggested possible resolutions for a 
>> Nickname Usage Conflict in the draft-ietf-stox-groupchat-00 
>> document.  In section 3.2, the document says
>> 
>> |   Alternatively [to translating the MSRP 425 message to a 
>> <conflict/> error], |   the gateway might generate a new
>> nickname request on |   behalf of the XMPP user, thus shielding
>> the XMPP client from handling |   the conflict error.
>> 
>> Additionally, section 5 says
>> 
>> |   If there is a conflict between the SIP nickname and the XMPP
>> | nickname, the SIP-to-XMPP or XMPP-to-SIP gateway is
>> responsible for |   adjusting the nickname to avoid the conflict
>> and for informing the |   SIP or XMPP client of the unique
>> nickname used to join the chatroom.
>> 
>> First, section 3.2 suggests that the gateway may choose to
>> generate a new nickname, but can instead merely forward on the
>> translated MSRP 425 or <conflict/> error, whereas section 5 says
>> that the gateway is responsible for (aka MUST) adjusting the
>> nickname in the event of a conflict.  Both of these sections
>> suggest that in the case of a nickname conflict the gateway may
>> act independently of the client to change the client-generated
>> nickname to one which is unique within the context of the
>> chatroom.  I'm not certain this is the most appropriate approach.
>> Nicknames are important in that they are needed to facilitate
>> private messaging and other features, as well as being an
>> important part of user identification.  It seems risky to
>> automatically generate a new nickname when a conflict is found,
>> instead of merely presenting the error to the user (via MSRP 425
>> message or <conflict/> error) so that they can choose a new
>> nickname via their client.  Additionally, a cursory examinatio n
>> of the XMPP, MSRP, and MUC RFCs/XEPs does not appear to show any
>> recommendation that nicknames be automatically generated in the
>> event of a conflict.
>> 
>> I believe that it would be better to require that the gateway 
>> merely forward on the translated MSRP 425 or <conflict/> error 
>> instead of attempting to address the conflict automatically, but
>> I may not sufficiently understand the reasoning behind the
>> automated nickname resolution.
>> 
> 
> I agree. This is how things are usually handled in MSRP. When
> testing things in XMPP however, not every client is able to
> properly deal with nickname conflicts though. Peter, maybe this was
> the reason why that text was added?

I doubt that was the reason, since I don't believe in designing
protocols around buggy software. :-)

Many XMPP clients will indeed shield the user from making a decision
about the nickname (e.g., if "stpeter" is taken they will cycle
through nicks like "stpeter1" or "stpeter_" or whatever). So pushing
an error back to the originating client seems fine to me in all cases.

Question: if the gateway were to choose a nick on behalf of the
client, are we sure that the chosen nick would get communicated back
to the originating client?

In any case, I think that what Mike proposes is sensible.

Peter

- -- 
Peter Saint-Andre
https://stpeter.im/


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