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<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'>We really don’t want to start encoding info into a GUID.
The RFC that describes them pretty much details what kinds of entropy can be
used. <o:p></o:p></span></p>
<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'><o:p> </o:p></span></p>
<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'>I’ve been thinking for a while that the handle service (<a
href="http://www.handle.net">http://www.handle.net</a>) might be a nice way to
do a URL style mechanism to refer to assets and such not on a local server.
It’s been a while since I looked at it but it’s pretty much
designed for the purpose and there’s a proxy architecture already defined
for it.<o:p></o:p></span></p>
<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'><o:p> </o:p></span></p>
<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'>Mike<o:p></o:p></span></p>
<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'><o:p> </o:p></span></p>
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<p class=MsoNormal><b><span style='font-size:10.0pt;font-family:"Tahoma","sans-serif";
color:windowtext'>From:</span></b><span style='font-size:10.0pt;font-family:
"Tahoma","sans-serif";color:windowtext'> opensim-users-bounces@lists.berlios.de
[mailto:opensim-users-bounces@lists.berlios.de] <b>On Behalf Of </b>Diva Canto<br>
<b>Sent:</b> Saturday, November 01, 2008 9:05 AM<br>
<b>To:</b> opensim-users@lists.berlios.de<br>
<b>Subject:</b> Re: [Opensim-users] [Opensim-dev] Grid Numberging<o:p></o:p></span></p>
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<p class=MsoNormal><o:p> </o:p></p>
<p class=MsoNormal>Actually, I just realized that the problem is already much
worse than I thought.<br>
The practices that we are all doing around opensim completely invalidate the
concept of uniqueness in UUIDs. This comes from the fact that UUIDs are being
externalized into DBs and XML representations, which are then being imported
elsewhere. As people reuse entire DBs and XML files to recreate the same worlds
in different grids, uniqueness goes down the drain. So definitely, forget about
"Universal" Unique Identification with UUIDs; uris/urls are
absolutely required for universal naming. The only way to savage UUIDs would be
use part of their representation to deterministically code up the ip/port of
where they come from.<br>
<br>
Stefan Andersson wrote: <o:p></o:p></p>
<p class=MsoNormal style='margin-bottom:12.0pt'>And the whole thread started
with suggesting we allocate information bits to encode semantics. Which
drastically heightens the risk of collisions, intentional or malicious.<br>
<br>
Just see guids as private to the trust domain, and we'll all fine. Grids should
be publicly referred to by something riches, as an uri/url for example.<br>
<br>
Best regards,<br>
Stefan Andersson<br>
Tribal Media AB<br>
<br>
Join the 3d web revolution : <a href="http://tribalnet.se/" target="_blank">http://tribalnet.se/</a><br>
<br>
<br>
<br>
<o:p></o:p></p>
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<p class=MsoNormal><br>
Date: Fri, 31 Oct 2008 20:10:41 -0700<br>
From: <a href="mailto:diva@metaverseink.com">diva@metaverseink.com</a><br>
To: <a href="mailto:opensim-users@lists.berlios.de">opensim-users@lists.berlios.de</a><br>
Subject: Re: [Opensim-users] [Opensim-dev] Grid Numberging<br>
<br>
Not to mention the dudes and dudettes who generate region UUIDs by hand...
(a-hem)<br>
Purely random UUIDs that don't encode higher-order information are too fragile
when there is a chance that people will get their hands on them. I'm not even
talking about malicious manipulation, just simple human intervention.<br>
<br>
Frisby, Adam wrote: <br>
<br>
<o:p></o:p></p>
<pre>Yeah, the reason I said 'almost' wasn’t because of a good UUID generator, - it's the bad ones.<o:p></o:p></pre><pre><o:p> </o:p></pre><pre>IE, people using bad random sources, etc which dramatically increase the chance of a collision - ie if you are only getting 30 bits of randomness, you could run into a collision fairly quickly.<o:p></o:p></pre><pre><o:p> </o:p></pre><pre>Adam<o:p></o:p></pre><pre><o:p> </o:p></pre><pre> <o:p></o:p></pre>
<blockquote style='margin-top:5.0pt;margin-bottom:5.0pt'><pre>-----Original Message-----<o:p></o:p></pre><pre>From: <a
href="mailto:opensim-users-bounces@lists.berlios.de">opensim-users-bounces@lists.berlios.de</a> [<a
href="mailto:opensim-users">mailto:opensim-users</a>-<o:p></o:p></pre><pre><a
href="mailto:bounces@lists.berlios.de">bounces@lists.berlios.de</a>] On Behalf Of Sean Dague<o:p></o:p></pre><pre>Sent: Friday, 31 October 2008 4:48 PM<o:p></o:p></pre><pre>To: <a
href="mailto:opensim-users@lists.berlios.de">opensim-users@lists.berlios.de</a><o:p></o:p></pre><pre>Subject: Re: [Opensim-users] [Opensim-dev] Grid Numberging<o:p></o:p></pre><pre><o:p> </o:p></pre><pre>Dr Scofield wrote:<o:p></o:p></pre><pre> <o:p></o:p></pre>
<blockquote style='margin-top:5.0pt;margin-bottom:5.0pt'><pre>Frisby, Adam wrote:<o:p></o:p></pre><pre> <o:p></o:p></pre>
<blockquote style='margin-top:5.0pt;margin-bottom:5.0pt'><pre>Shouldn’t UUIDs by definition be unique?<o:p></o:p></pre><pre><o:p> </o:p></pre><pre><o:p> </o:p></pre><pre><o:p> </o:p></pre><pre>IE – if your generating them randomly a collision is almost<o:p></o:p></pre><pre>guaranteed to never ever occur.<o:p></o:p></pre><pre> <o:p></o:p></pre></blockquote>
<pre>"almost" being a key word here...<o:p></o:p></pre><pre> <o:p></o:p></pre></blockquote>
<pre>"...after generating 1 billion UUIDs every second for the next 100<o:p></o:p></pre><pre>years, the probability of creating just one duplicate would be about<o:p></o:p></pre><pre>50%. The probability of one duplicate would be about 50% if every<o:p></o:p></pre><pre>person on earth owns 600 million UUIDs.<a
href="http://en.wikipedia.org/wiki/UuidJusttokeep" target="_blank">"<o:p></o:p></a></pre><pre><span
class=MsoHyperlink><a href="http://en.wikipedia.org/wiki/UuidJusttokeep"
target="_blank"><o:p><span style='text-decoration:none'> </span></o:p></a></span></pre><pre><span
class=MsoHyperlink><a href="http://en.wikipedia.org/wiki/UuidJusttokeep"
target="_blank">http://en.wikipedia.org/wiki/Uuid<o:p></o:p></a></span></pre><pre><span
class=MsoHyperlink><a href="http://en.wikipedia.org/wiki/UuidJusttokeep"
target="_blank"><o:p><span style='text-decoration:none'> </span></o:p></a></span></pre><pre><span
class=MsoHyperlink><a href="http://en.wikipedia.org/wiki/UuidJusttokeep"
target="_blank">Just to keep "</a></span>almost" in perspective,<o:p></o:p></pre><pre><o:p> </o:p></pre><pre> -Sean<o:p></o:p></pre><pre><o:p> </o:p></pre><pre>--<o:p></o:p></pre><pre>Sean Dague / Neas Bade<o:p></o:p></pre><pre><a
href="mailto:sdague@gmail.com">sdague@gmail.com</a><o:p></o:p></pre><pre><a
href="http://dague.net/" target="_blank">http://dague.net</a><o:p></o:p></pre><pre><o:p> </o:p></pre><pre> <o:p></o:p></pre></blockquote>
<pre>_______________________________________________<o:p></o:p></pre><pre>Opensim-users mailing list<o:p></o:p></pre><pre><a
href="mailto:Opensim-users@lists.berlios.de">Opensim-users@lists.berlios.de</a><o:p></o:p></pre><pre><a
href="https://lists.berlios.de/mailman/listinfo/opensim-users" target="_blank">https://lists.berlios.de/mailman/listinfo/opensim-users</a><o:p></o:p></pre><pre><o:p> </o:p></pre><pre> <o:p></o:p></pre>
<p class=MsoNormal><br>
<br>
<o:p></o:p></p>
<pre><o:p> </o:p></pre><pre style='text-align:center'>
<hr size=4 width="90%" align=center>
</pre><pre><o:p> </o:p></pre><pre>_______________________________________________<o:p></o:p></pre><pre>Opensim-users mailing list<o:p></o:p></pre><pre><a
href="mailto:Opensim-users@lists.berlios.de">Opensim-users@lists.berlios.de</a><o:p></o:p></pre><pre><a
href="https://lists.berlios.de/mailman/listinfo/opensim-users">https://lists.berlios.de/mailman/listinfo/opensim-users</a><o:p></o:p></pre><pre> <o:p></o:p></pre>
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