[or-cvs] r11239: Merge a condensed proposal 108 (without too much implementat (in tor/trunk: . doc/spec)

[nickm at seul.org]

Author: nickm
Date: 2007-08-21 01:37:21 -0400 (Tue, 21 Aug 2007)
New Revision: 11239

Modified:
   tor/trunk/
   tor/trunk/doc/spec/dir-spec.txt
Log:
 r14757 at catbus:  nickm | 2007-08-21 01:35:24 -0400
 Merge a condensed proposal 108 (without too much implementation detail, since that's implementation detail, into dir-spec.txt.



Property changes on: tor/trunk
___________________________________________________________________
 svk:merge ticket from /tor/trunk [r14757] on 8246c3cf-6607-4228-993b-4d95d33730f1

Modified: tor/trunk/doc/spec/dir-spec.txt
===================================================================
--- tor/trunk/doc/spec/dir-spec.txt	2007-08-21 05:37:19 UTC (rev 11238)
+++ tor/trunk/doc/spec/dir-spec.txt	2007-08-21 05:37:21 UTC (rev 11239)
@@ -937,12 +937,22 @@
    "Running" -- A router is 'Running' if the authority managed to connect to
    it successfully within the last 30 minutes.
 
+
    "Stable" -- A router is 'Stable' if it is active, and either its
-   uptime is at least the median uptime for known active routers or
-   its uptime is at least 30 days. Routers are never called stable if
+   Weighted MTBF is at least the median for known active routers or
+   its Weighted MTBF is at least 10 days. Routers are never called Stable if
    they are running a version of Tor known to drop circuits stupidly.
    (0.1.1.10-alpha through 0.1.1.16-rc are stupid this way.)
 
+        To calculate weighted MTBF, compute the weighted mean of the lengths
+        of all intervals when the router was observed to be up, weighting
+        intervals by $\alpha^n$, where $n$ is the amount of time that has
+        passed since the interval ended, and $\alpha$ is chosen so that
+        measurements over approximately one month old no longer influence the
+        weighted MTBF much.
+
+        [XXXX what happens when we have less than 4 days of MTBF info.]
+
    "Fast" -- A router is 'Fast' if it is active, and its bandwidth is
    either in the top 7/8ths for known active routers or at least 100KB/s.