[freenet-dev] Statistics Project Update #1
On Tue, May 1, 2012 at 7:48 AM, Zlatin Balevsky wrote: >> On 04/28/2012 06:56 PM, Zlatin Balevsky wrote: >>> In Gnutella we observed that long-lived nodes tend to be better >>> connected and that they also cluster with other high-uptime nodes. >>> If the same is true for Freenet it's a good idea to keep an eye for >>> side effects as you tweak the behavior. >> >> Good to know - I'll look for that. Are there any particular effects >> you had in mind? The Metropolis-Hastings correction in the new probes >> should produce a fairly uniform distribution of endpoints despite >> clustering and well-connected nodes, but explicitly simulating the >> effects of high uptime could be helpful. > > There was a study that higher uptime correlated with the probability > of further uptime so if you shift bias towards low-uptime nodes you > could end will lower overall reliability. ?It was done on a different > network with different usage patterns but imho you should definitely > treat node uptime as a parameter in any simulations. > ___ > Devl mailing list > Devl at freenetproject.org > https://emu.freenetproject.org/cgi-bin/mailman/listinfo/devl MH should produce a good simple random sample from all nodes currently online, provided that the walk is of sufficient length, regardless of clustering effects. If there are partitioning effects, those will make the required walk length to get good dispersion longer, in a way that might be somewhat difficult to measure, but as long as the network is not completely partitioned, a sufficient walk length will produce a good sample. The fact that a large sample must be taken over an extended period means that low-uptime nodes will have a somewhat disproportionately lower chance of being in the sample (I think... need to do math here), but isn't a huge problem. Evan Daniel
Re: [freenet-dev] Statistics Project Update #1
On Tue, May 1, 2012 at 7:48 AM, Zlatin Balevsky zlat...@gmail.com wrote: On 04/28/2012 06:56 PM, Zlatin Balevsky wrote: In Gnutella we observed that long-lived nodes tend to be better connected and that they also cluster with other high-uptime nodes. If the same is true for Freenet it's a good idea to keep an eye for side effects as you tweak the behavior. Good to know - I'll look for that. Are there any particular effects you had in mind? The Metropolis-Hastings correction in the new probes should produce a fairly uniform distribution of endpoints despite clustering and well-connected nodes, but explicitly simulating the effects of high uptime could be helpful. There was a study that higher uptime correlated with the probability of further uptime so if you shift bias towards low-uptime nodes you could end will lower overall reliability. It was done on a different network with different usage patterns but imho you should definitely treat node uptime as a parameter in any simulations. ___ Devl mailing list Devl@freenetproject.org https://emu.freenetproject.org/cgi-bin/mailman/listinfo/devl MH should produce a good simple random sample from all nodes currently online, provided that the walk is of sufficient length, regardless of clustering effects. If there are partitioning effects, those will make the required walk length to get good dispersion longer, in a way that might be somewhat difficult to measure, but as long as the network is not completely partitioned, a sufficient walk length will produce a good sample. The fact that a large sample must be taken over an extended period means that low-uptime nodes will have a somewhat disproportionately lower chance of being in the sample (I think... need to do math here), but isn't a huge problem. Evan Daniel ___ Devl mailing list Devl@freenetproject.org https://emu.freenetproject.org/cgi-bin/mailman/listinfo/devl
