On Wed, Jan 22, 2014 at 01:02:29PM -0500, [email protected] wrote: > >Also keep in mind that what the bandwidth > >authorities actually measure is not total capacity > >but spare stream capacity (by downloading large > >files through at least 5 different two hop > >circuits times for each relay). > > Wait... So if I understand this correctly > the bandwidth number is the difference between > the actual bandwidth of the node and the > actively utilized bandwidth?
No. The bandwidth number is how much attention clients should give the relay. That is, it's a weighting that clients use when selecting relays, and they select a given relay proportional to its bandwidth weight. > I looked high-and-low for a proper definition > of the value This is where the consensus weight is described: https://gitweb.torproject.org/torspec.git/blob/HEAD:/dir-spec.txt#l1634 The consensus weight is computed using a) the relay's self-advertised bandwidth in its descriptor: https://gitweb.torproject.org/torspec.git/blob/HEAD:/dir-spec.txt#l389 b) the ratios of bandwidth weights for various types of relays: https://gitweb.torproject.org/torspec.git/blob/HEAD:/dir-spec.txt#l2137 and c) the result of the active measurements from the bandwidth authorities: https://gitweb.torproject.org/torflow.git/blob/HEAD:/NetworkScanners/BwAuthority/README.BwAuthorities https://gitweb.torproject.org/torflow.git/blob/HEAD:/NetworkScanners/BwAuthority/README.spec.txt > However I must complain that the consensus > bandwidth does not say much about the > relative health of a relay. Does a good > (ungamable) way exist to show the bandwidth > capacity of relays along with the available > capacity? Ungameable is a much harder requirement. See e.g. http://freehaven.net/anonbib/#eigenspeed but Eigenspeed does not do well at assessing the speed of fast relays, since it's hard to design a system where relays can accurately assess the speed of faster relays. --Roger _______________________________________________ tor-relays mailing list [email protected] https://lists.torproject.org/cgi-bin/mailman/listinfo/tor-relays
