At 16:19 10/15/2013 -0400, starlight@binnacle.cx wrote:

Question:

What the difference between the bandwidth value given by getinfo ns/name/xxxxx

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w Bandwidth=297

and getinfo dir/server/authority

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bandwidth 300000 375000 335872

Since no one answered the question and I now have an idea about it, I'll attempt an answer for future web-searchers. . .

getinfo ns/name/<node-name>

This appears to be a consensus bandwidth calculation generated by five of the nine Tor authority nodes. These nodes run a special relay control client that accumulates and analyzes bandwidth reporting by other Tor nodes via "signal" updates from a daemon control channel. Think they are called 'bwauth's.

The value can swing wildly, but appears that the pattern is sinusoidal with an average close to the true bandwidth available from a relay. After a few days the swings in the value seem to dampen somewhat.

This "consensus bandwidth" value appears to be what is used by the client nodes' relay path selection algorithm.

getinfo dir/server/authority

This appears to the observed bandwidth calculation derived from local node statistics. Is much more stable and accurate, but is "informational" and is not used in the path selection algorithms.