[tor-bugs] #7177 [Torflow]: Understand how accurate the bandwidth authority estimates are

Tor Bug Tracker & Wiki torproject-admin at torproject.org
Thu Oct 25 13:03:02 UTC 2012


#7177: Understand how accurate the bandwidth authority estimates are
----------------------+-----------------------------------------------------
 Reporter:  karsten   |          Owner:  aagbsn
     Type:  project   |         Status:  new   
 Priority:  normal    |      Milestone:        
Component:  Torflow   |        Version:        
 Keywords:  SponsorZ  |         Parent:        
   Points:            |   Actualpoints:        
----------------------+-----------------------------------------------------
Changes (by aagbsn):

 * cc: gamambel (added)


Comment:

 Replying to [ticket:7177 karsten]:
 > (Re-using text from Roger and Mike for this ticket description.)
 >
 > It would be good to have a better understanding of how accurate the
 bandwidth authority estimates are.  Why do some really fast relays get
 huge weights, and other really fast relays don't?  Does it have to do with
 location of the measurers?  What exactly is the trade-off between having
 fast nodes all nearby each other (and nearby the bandwidth authorities) in
 the network, and having nodes in geographically dispersed places?

 Can we come up with a list of "really fast relays" that don't have huge
 weights? I've seen an exit operator complain that his/her exit in the same
 datacenter as another exit does not see similar performance [1]. I'd guess
 that this means it's probably a difference in the exit configuration
 rather than geographic location, and since the faster relay was operated
 by torservers.net I pointed the operator at their wiki which contains more
 details about the server configuration (e.g., tcp stack tuning)[2]. Maybe
 we can simulate circuits of varying latency and see how these tunables
 affect results?

 [1] https://lists.torproject.org/pipermail/tor-
 relays/2012-October/001689.html
 [2]
 https://www.torservers.net/wiki/setup/server#high_bandwidth_tweaks_100_mbps

 >
 > We probably should figure out a way for the bandwidth authorities to
 utilize per-node as well as ambient circuit failure (#7023, #7037).

 >
 > There's a bunch of related stuff for TCP socket exhaustion, too.  All of
 it probably involves some fairly diligent monitoring of results and
 experimentation though.

-- 
Ticket URL: <https://trac.torproject.org/projects/tor/ticket/7177#comment:2>
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