Subject: [Simple] Re: Chat Nicknames

From: "Niemi Aki (Nokia-M/Espoo)" <[email-masked]>
Date: Mon, 01 Mar 2004 10:24:03 +0200

ext Cullen Jennings wrote:
> I might be missing the boat here but let me ask a question that separates
> stuff. 

I doubt it. I think this particular boat is still covered up in storage, 
waiting for spring. ;)

> Is there a requirement to be able to change you nickname on every message or
> would it be acceptable to set up a new session if you want to change you
> nickname?

I think the requirement is definitely to require a re-INVITE (or 
equivalent) to change the nickname. In fact, once the nick is set within 
the conference, the server ought to administer it as well. Otherwise 
users could impersonate others in the conference.

As I commented in SIPPING this morning, this has many similarities to 
the identity stuff anyway. It's just that in this case, the UAS that the 
UAC wants to tell its name is a conference focus.

One might also imagine a system, where the conference server can assert 
a nickname that has been properly set up beforehand. For example, 
example.com's conference server might have an interface for requesting 
and getting nicknames, perhaps bootstrapped to some existing credentials 
the user may have at example.com. These nicknames could then be used in 
all conferences at that domain.

This would prohibit anyone from stealing a nickname, since it would 
persist over conferences, and the fact that the conference server had 
asserted the nickname could be seen by the other participants.

Similar functionality exists on Internet chatboards, where visitors can 
still post (using an invented nickname), but registered users are 
offered perks like avatars and wider priviledges (and their nickname 
can't be stolen).

> It seems that the name could be set when you set up the session. If this is
> the case, then the display name of the From is very clear you can put any
> alias you want in it. The chat controller can tell you that name is not
> acceptable thought, in practice, there is no fundamental reason you can't
> have people with the same nickname and just have the conf server append
> something to make them unique.

Yes, that's possible. However, how would a participant joining a 
conference request that the From is used instead of, say, 
P-Asserted-Identity? Also, changing the entire From suffers from the rfc 
2543 compatibility problems already mentioned elsewhere. I can also 
think of scenarios where the display name alone is not enough, but there 
is a need for a URI as well. E.g., From/To in CPIM is a display name and 
a URI. This URI may not always be a SIP URI.

> RTP/RTCP had different requirements for this because you could join a
> multicast session with effectively no signaling with all the participants so
> there was a need to continuously and adaptively flow the name information as
> the conference changed. Since this this centralized conferencing, you can
> get the names from the centralized thing.

Exactly. And the centralized point should also police the used nicknames 
so that I won't be able to send messages using someone else's nickname.

> Say two people joined with nick name of anon. The chat mixer may identify
> them as anon1 and anon2 in the session and you can send a private message to
> one of them by sending to location for anon2 (which would be an anonymous
> perhaps on the same box as the mixing was happening on).

Yes, that would work also.

Cheers,
Aki

> Cullen

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From: "Niemi Aki (Nokia-M/Espoo)" <[email-masked]>
Date: Mon, 01 Mar 2004 10:24:03 +0200

Cheers,
Aki

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From: Cullen Jennings <[email-masked]>
Date: Fri, 27 Feb 2004 16:10:50 +0900

Cullen