On 3/20/2010 4:43 PM, Michael Rueger wrote:
On 3/20/10 4:35 PM, Marcus Denker wrote:
So why does everyone ignore TeaTime? I admit I don't understand the internals, but it obviously *looks* like it could be the basis of Nebraska (or any other P2P solution).
Can you point me to a real good publication about it? I mean, a *real* one?
AFAIK TeaTime never happened but they (Croquet/Cobalt) switched to some multiplayer game like sync scheme (at least the poor me understood when I saw the implementation ;-) ).
Actually we didn't. TeaTime (as conceived by David Reed) consisted of two separate ideas, namely that of a world synchronization protocol and that of a P2P network protocol. When David Smith and I implemented the version we shipped in Hedgehog we dropped the P2P network protocol part and only concentrated on the synchronization aspect which resulted in *major* simplifications. That turned out to be a real win because the original design required N^2 connections for N participants with the obvious resulting problems if you get to larger numbers of users (today we can run sessions in Teleplace with 250+ active participants). David and I originally replaced the P2P communication with a single central entity (the router) but today this is actually a router overlay network that gives us theoretical scalability to 10,000s of users in the same space (unfortunately the client currently cannot cope with the rendering of all the stuff today at scales > 250). Anyway. The important part is that due to the practical connectivity restrictions for most users (bandwidth, latency, firewalls) running purely P2P is really stupid. You need a fixed point outside the firewall that you connect to via TCP through proxy and whatever BS the local environment requires and from that fixed point it goes into the overlay network. This has many additional advantages that I won't elaborate on here. As for publications, I don't know what amounts for a "real" publication in your eyes Marcus but considering that neither David nor myself are measured by number or quality of our publications you'll have to do with the publications listed at http://opencroquet.org/index.php/Overview I would in particular recommend the Hedgehog architecture presentation at http://opencroquet.org/images/e/ee/2005_Hedgehog_Architecture.pdf which is from the talk David and I gave at the OOPSLA workshop. As you look at the presentation read the documentation at http://opencroquet.org/index.php/Croquet_SDK which talks about the stuff in the slides. Coincidentally, I am toying regularly with the idea of using an even more simplified version of TeaTime to do something like Nebraska. Might get around to it one of these days, it's actually straightforward. BTW, it's a misconception to think TeaTime is something complicated. Complicated things don't work. Simple things do. TeaTime is actually VERY simple. That's why it works. Cheers, - Andreas