Subject: Session Initiation protocol and videogame consoles

From: [email-masked] (Dan Kolis)
Date: Thu, 16 May 2002 09:27:05 -0400

Hi to all,

Does anyone know of active work to encapsulate multi-player
videogames inside Session initiation protocol?

I guess I'm considering doing this. Especially curious if someone who
is pretty sure about it could suggest the protocol SIP sould suggest
for the stream from the game. The idea being running processes
(usually games) that don't know their inside SIP.

Would it be RTP? Ethernet tunnelling maybe?

Also in the session would be codec(s) of course.

Regards,
Dan

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From: "John Stracke" <[email-masked]>
Date: Thu, 16 May 2002 11:18:02 -0400

>The idea being running processes

Huh.  Well, if you've got a game that thinks it's just running over IP, or 
over Ethernet, then you don't really need RTP's timestamps.  On the other 
hand, you also don't need the reliability of SIP-level messages--and those 
would be a larger problem than the timestamps, because the game's protocol 
might include some bits that should be unreliable (e.g., if audio 
streams).

I suppose you could (on the right OS) set up an IP interface, or a dummy 
Ethernet device, that actually tunnels over a SIP session.  (Make sure you 
had a sufficiently unique MAC address, of course.) The hard part would be 
doing it securely--if you're behind a firewall, you need to make sure that 
your virtual network has filtering at least as strong as your physical 
network.  With an OS like the HURD (when it's ready), or maybe Plan 9, you 
could make that interface available only to the process(es) running the 
game; that would contain the amount of damage that could be done.

None of this is really the Right Thing, of course; what you really want is 
a gaming protocol that actually runs over SIP, instead of having to tunnel 
it.

/=================================================================\
|John Stracke                    |Principal Engineer              |
[email-masked]   |Incentive Systems, Inc.         |
|http://www.incentivesystems.com |My opinions are my own.         |
|=================================================================|
|"Your reality, sir, is lies & balderdash, and I am pleased to say|
|I have no grasp on it whatsoever!" --Baron Munchausen            |
\=================================================================/

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From: "Christian Huitema" <[email-masked]>
Date: Thu, 16 May 2002 09:39:55 -0700

> might include some bits that should be unreliable (e.g., if audio

Tunneling protocol data inside SIP is generally considered a bad idea,
as it would dramatically alter the workload of the SIP servers. It is
also a bit weird. If you think about it that would be pretty much like
sending game messages as instant messages. That may work for announcing
your chess moves, but if you try that with a first person shooter
neither the IM provider not the game player are going to like the
result.

The architecturally correct way to use SIP for games is to use a SIP
exchange to initiate a game session, i.e. invite "sip:[email-masked]"
to join a game. The payload of the SIP messages (INVITE and response)
will carry the IP address and port numbers used by the game application.

-- Christian Huitema