On Mon, Oct 13, 2003 at 12:34:21PM +0200, Some Guy wrote: > --- Todd Walton <[EMAIL PROTECTED]> wrote: > > On Sun, 12 Oct 2003, Benjamin Coates wrote: > > > > > A discussion on #freenet leads me to suggesting this change to QueryReject > > > behavior: > > > > > > The goal here is to reduce the message traffic to overloaded nodes without > > > seriously changing network behavior. > > > > What advantage does this have over the way it already happens, i.e. > > NGRouting. With NGRouting, if a node is overloaded and QRs, everybody > > adjusts their appraisal of the node downwards, and message traffic to that > > overloaded node is reduced. > > > > What advantage does your above idea offer over the NGRouting effect? > > > > (Not that there are no advantages, just asking what they are.) > Be Nice. > > NGR and the old routing take a long time (hours) to train up. So, they would also > take a while to > "train down". This is probably too slow to react to some overload problems.
NGR should react pretty quickly to QueryRejects. It's not an estimator it's just a decaying average. > > You may also argue that the rejections caused by overload as noise, which if treated > the same as > normal DNFs muck up the picture and make it that much harder for NGR or LGR (last > generation > routing) to learn. > > For these reasons, it seems like you'd want to have special DNFs to let overloaded > nodes say hey > "leave me alone for a bit". > > That said I do understand why it seems cleaner to let NGR handle the problem. > --------- > My suggestion: Look at how Ethernet worked on coax. You'd broadcast your message > and if you got a > collision, back off for a random period and try again. For every repeated failure > you'd double > the wait time until some high limit. > > It can be shown that such a simple algorithm can allow a theoretically infinite > number of devices > to get an equal share of the media, without the collisions wasting more than a > particular fraction > of the bandwidth (I think <70% for ethernet). > > The problem is similar with an overloaded freenet node: > We have a limited resource. > We don't know who all is using it. > If we all jump on it, it won't be able to service any of us, because all upbandwidth > will be used > in rejecting messages. > > Maybe if all the nodes would back-off exponentially on overload DNFs, we wouldn't > get those 16.88% > accepted queries Mathew reffered to in his next post. -- Matthew J Toseland - [EMAIL PROTECTED] Freenet Project Official Codemonkey - http://freenetproject.org/ ICTHUS - Nothing is impossible. Our Boss says so.
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