[tor-bugs] #2536 [Tor Relay]: Disable outgoing token bucket and reduce token bucket refill interval

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#2536: Disable outgoing token bucket and reduce token bucket refill interval
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 Reporter:  karsten      |          Owner:  karsten           
     Type:  enhancement  |         Status:  assigned          
 Priority:  normal       |      Milestone:  Tor: 0.2.3.x-final
Component:  Tor Relay    |        Version:                    
 Keywords:               |         Parent:                    
   Points:               |   Actualpoints:                    
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Comment(by Bjoern):

 Replying to [comment:13 Sebastian]:
 > What happens to the current notion of a bandwidthburst? That is probably
 what M wants to be based on somehow, yes?

 We need to distinguish two burst sizes, in the incoming and the outgoing
 direction. The incoming burst size is, just like before, given by the size
 of the token bucket on the incoming side; let me denote this size by T
 here. For the outgoing side, we have, analogously, a size S for the credit
 bucket. Then, there is a hard limit of M+S+T on the outgoing burst size:
 in the extreme case, the incoming bucket is full (x=T) and the credit
 bucket on the outgoing side is also full (y=S), so we may send out M+S+T
 bytes immediately. This may happen if (a) there has been lots of incoming
 traffic which "vanished" inside the router before (so that the credit
 bucket became full) and (b) there is currently no incoming traffic (so
 that the incoming bucket ran full, too), and (c) lots of outgoing traffic
 is spontaneously generated within the router.

 To reliably avoid double-dooring, S and M should both be at least a few
 times larger than T. To be on the absolutely safe side, we could either
 have separate configuration parameters for M, S, and T, or we could have
 one maximum burst size parameter b and would internally use a fixed ratio
 between the sizes, e.g., T = 0.1*b, S=0.45*b, M = 0.45*b.

 For good performance, it will of course be essential to configure a
 sufficiently large burst size. This should be communicated in the
 documentation.

-- 
Ticket URL: <https://trac.torproject.org/projects/tor/ticket/2536#comment:14>
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