On 21/11/14 23:05, Lei Yang wrote:
Dear Dr. Loesing,
I have a concern about the consensus_weight. The definition of it seems that the consensus_weight is a completely measured value by the authorities. However, from the Bandwidth Scanner Specification, if I understand correctly, it looks like a combination of observed bandwidth and the measured bandwidth. This is the description about how to calculate the consensus weight in the Bandwidth Scanner Specification, "we compute an average of the filt_bw fields over all nodes we have measured. These averages are used to produce ratios for each node by dividing the measured value for that node by the network average. These ratios are then multiplied by the most recent observed descriptor bandwidth we have available for each node, to produce a new value for the network status consensus process."
If I am wrong, could you please let me know? Thank you very much!
Hi Lei,
thanks for your feedback. You're correct that the consensus weight is based on observed and measured bandwidth. The definition I wrote was an attempt to put the consensus weight, which is to some extent verified by third parties, in contrast to advertised/observed bandwidth, which is entirely self-reported by relays. Let me try to make the definition slightly more correct without making it unnecessarily complex:
""" consensus weight: value assigned to a [relay] that is based on bandwidth observed by the relay and bandwidth measured by the [directory authorities], included in the hourly published consensus document, and used by [clients] to select relays for their [circuits]. """
Does this definition sound okay? Anything else I can tweak?
Obviously, this definition is not as precise as the definitions given in the Bandwidth Scanner Specification. The idea is that whoever reads specification documents doesn't need to read the shorter definitions on the Tor Metrics website. But at the same time people shouldn't get confused by oversimplified definitions.
Again, thanks for your input!
All the best, Karsten