[sldev] [AWG] Comments on SLGOGP Draft 1

[Lawson English]

Ben Francis wrote:
> Dear list,
>
> I've just been reading the first draft of the Open Grid Protocol and 
> listening to the audio recording of the second Architecture Working 
> Group meeting and it has got me interested.
>

I hope you've managed to read a few of the chatlogs of AW Groupies 
in-world meetings and Zero's office hours and so on, which give context 
to the second meeting:

https://wiki.secondlife.com/wiki/AW_Groupies#Activities


> == Quick Introduction ==
>
> By way of introduction I am an undergraduate at the University of 
> Birmingham [1] reading MEng Computer Interactive Systems and my final 
> year masters project next year will hopefully be on 3D Web technology. 
> I'm also currently in the very early stages of founding Krellian [2] 
> and the not-for-profit Krellian Foundation [3].
>
> I have never been involved in any standardisation work before but am 
> an advocate of open standards and have an interest in online 3D 
> worlds. Although an occasional Second Life user I know very little 
> about the current Second Life architecture and come from a web 
> programming background, so tend to see online virtual worlds as the 
> "3D Web", a direct extension of the existing web. I think this is a 
> slightly different way of looking at things than the current approach 
> taken by Second Life.
>
> What most interests me about the AWG discussions is how open the group 
> appears to be to utilising relevant existing standards rather than 
> attempting to re-invent new ones.

Except where needed. You should talk to Zero Linden (Mark Lentczner of 
Linden Lab) and Zha Ewry (David Levine of IBM) about issues with using 
XMPP for IM in Second Life, especially in the super-grid that a 
full-blown 3D web would involve with billions of accounts, 50-100 
million avatars online, etc.

>
> A particularly interesting technology mentioned was XMPP. The obvious 
> application of this is for Instant Messaging and presence, 
As above for IM and understand that "presence" in Second Life will have 
two, possibly three distinct stages, and that XMPP's "presence" may not 
address them as well as you might expect.




> but I think the most important use is as a general point-to-point 
> protocol. I have thought about using XMPP in realtime web apps before 
> to overcome the limitations and asynchronous nature of HTTP, but have 
> never actually come close to implementing it. In my opinion using XMPP 
> would certainly be preferable to inventing a new TCP or UDP based 
> protocol in cases where HTTP is not suitable, providing it stands up 
> to the requirements. I understand XMPP [9] to be very extensible.
>
> It seems odd to discuss open standards for the 3D Web without 
> mentioning the Web3D Consortium [10] and X3D. Are there 
> representatives from Web3D involved in the discussions and how would 
> X3D fit into this proposed architecture?
>

Second Life is an existing system with exceedingly poor documentation 
and protocols that are in total flux. There's no point in seeking out 
standards bodies until the new protocols are in place and documented 
sufficiently well that they can be critiqued. As for X3D, I don't think 
its quite up to handling SL and other large-scale virtual worlds 
requirements, though I may be wrong, of course.



> == Scope and general approach ==
>
> Overall the basic structure of the proposed protocols is similar to 
> the way I envisaged the 3D Web on my web site [11] (apologies for 
> referring to Second Life as the "AOL of the 3D Web" on that page :P ). 
> In that design concept I called the "Viewer" a "3D Web Browser", the 
> "Agent Domain" an "Avatar Server" and the "Region Domain" simply the 
> "3D Web Server". I also covered a lot of relevant points in my 
> response [12] to a blog post by Bob Sutor of IBM where he listed the 
> requirements of his ideal virtual world.
>
> I can not find a clear definition of the scope of the AWG 
> specification. The current standardisation approach seems very 
> bottom-up, focusing on matching standards to features that are known 
> to exist in Second Life.
That is because the AWG itself is dedicated to supporting the 2-year 
plan of Linden Lab, to open up the *Second Life* grid to third parities 
willing to use the protocols that are compatible with  Second Life as it 
is projected to exist 2 years from now. Trying to accommodate virtual 
worlds that haven't been designed  to be 100% compatible with Second 
Life is a much more difficult goal. The IBM-Linden Lab project to create 
a portable avatar standard is more along those lines. The AW Groupies 
theoretical discussions wander into that territory quite often as well. 
There are several Second Life-related projects that are looking to 
extend the SL capabilities  in various ways not necessarily envisioned 
by Linden Lab, and the contact info for them is found here:

https://wiki.secondlife.com/wiki/AW_Groupies#External_Resources

There are other groups and organizations where Second Life isn't the 
central focus which may be more what you are looking for in that regard, 
such as Croquet/Qwak, Wonderland and so on, though of course, each of 
them is more closed in some ways than Second Life is expected to become.



> I would be interested to see a little more top-down work to more 
> precisely define the scope of exactly what is being standardised and 
> how this fits into the wider world of Internet standards. For example, 
> I personally feel that although instant messaging and the concept of 
> currency are inevitably used in online virtual worlds, they are not a 
> required part of the core specification. Currency and instant 
> messaging in a 3D world should simply be a 3D front end to existing 
> systems (in the same way that meebo.com is a front end to a jabber 
> service, the web browser does not need to support XMPP).
>

As I said, the AWG's focus is on virtual worlds that are 100% compatible 
with Second Life. Trying to accommodate 3rd party money and IM that 
aren'tt compatible with Linden Lab's own offerings is a far more 
difficult goal --one that the AWG isn't looking at. The AW Groupies 
meetings discuss this, and Open Sim has a more open stance on these 
issues. See above for Open Sim contacts.

> This is probably quite obvious but I also think there should be no 
> *enforcement* of a topology which requires that virtual spaces have a 
> constant position relative to each other (i.e. "teleporting" should be 
> the same as clicking on hyperlinks in text web pages, where you jump 
> between spaces rather than having to navigate around them spatially as 
> in the real world). That way, the closeness of two spaces is measured 
> by interest rather than spatial dimensions.
>
In Zero Linden's vision, a grid topography reveals asset trust: if you 
can walk from one grid to the next in the same way you can walk from one 
Second Life region to the next, it is an assurance to the avatar that 
asset and monetary issues behave the same in both worlds. Working with 
two different "grids" that may not even be grids is another issue that 
goes beyond the AWG's near-term goals, though TP between them should 
obviously be possible if they both accept the same TP protocols.



> == Context ==
>
> Something which interests me personally is how the 3D Web fits in the 
> context of the rest of the World Wide Web and the rest of the Internet.
>
> I would like to see a World Wide Web where a URI identifies a 
> resource, but that resource can have many representations. Those 
> representations may include rich text (XHTML), 2D vector graphics 
> (SVG), a speech dialogue (VoiceXML) or an interactive 3D world (X3D?). 
> Content Negotiation in HTTP could then be used to negotiate a 
> representation format between the web server and web user agent (or 
> the "region domain" and "agent domain"). The user could switch between 
> these different representations based on hardware capabilities, 
> personal abilities and current user environment.
>
> This may require certain distinctions between the server and user 
> agent which are not currently part of the AWG proposed protocols.
>
> Would this be something that could form the basis for a "Device 
> Independence" Viewpoint Advocacy Group?
>
>
I'm sure there are plenty of people who are interested in this. You 
should come to AW Groupies meetings, Zero's office hours, as well as 
talk to the Open SIm, realXtend, openviewer people. Other virtual worlds 
have other contact points, but none are as open in the sense of being 
open source AND open protocol as the groups I've listed in the AW 
Groupies external links, or so I believe.

AW Groupies meetings happen every Tuesday morning in-world at 9:30 am 
Second Life Time (Pacific Coast Time). I won't be attending this next 
one, but you can contact Zha Ewry or Tree Kyomoon for a group invite to 
get to the meeting.

Zero LInden's office hours are Tuesdays at 1PM SLT and Thursdays at 8:30 
AM SLT.

Contacts for other groups related to Second Life are found on the AW 
Groupies page:

https://wiki.secondlife.com/wiki/AW_Groupies


Hope to see you at the various meetings. Sounds like you have a lot to 
contribute.

Lawson (Saijanai Kuhn)