Not that I'm aware of. The current plan is to see if it appears under a network running Opennet (path folding) with added churn (nodes joining for a while taking a randomized position, participating some in swapping, then disappearing for good).
Simulating a darknet-style network about if this is happening is more complicated, I don't know of a straightforward way to simulate churn where nodes leave for good in a darknet and with new ones arriving being placed well in the topology (with no path folding). Vilhelm On Wed, Aug 15, 2007 at 12:14:16PM -0500, Ian Clarke wrote: > Indeed, have we actually replicated the clustering effect with churn in a > simulation? > Ian. > > On 8/14/07, Matthew Toseland <toad at amphibian.dyndns.org> wrote: > > > > The reasons we need periodic randomization are 1) churn results in > > clustering > > and 2) attacks. So it would be interesting to look at it with some churn. > > > > I'll have a look at the rest tomorrow. > > > > On Tuesday 14 August 2007 21:50, vive wrote: > > > Here are some experiments on running the swapping algorithm with > > periodic > > > randomization of node positions. The idea is to study measures against > > > position clustering, and later on what can be made to counter attacks > > > against the swap algorithm. No attacks have been simulated yet, this is > > the > > > pure impact of randomizing positions on the swapping algorithm. > > > > > > The network size was fixed to 10000 nodes, HTL to 100, and the average > > > degree was varied. Each run a network was initiated as the Kleinberg > > model, > > > measured by routing a while on it, and then positions were uniformly > > > randomly assigned between 0 and 1 before staring the swapping algorithm > > to > > > recover the efficient routing. > > > > > > The major thing to study was the frequency of randomizing the position. > > One > > > run was evaluated for each different frequency X. Randomizing frequency > > X > > > was used as follows: each node randomizes its location each X'th swap > > that > > > goes out from that node. To avoid cyclic behaviour (at least of the > > simple > > > case, perhaps this needs to be extended) each nodes counter for doing > > this > > > is initialized independenty between 0 and X before starting the > > > simulations. Lets say a node randomly initalizes its counter to y > > (between > > > 0 and X), then it will randomize its location on the swap > > > y,y+X,y+2X,y+3X... that starts from it with a random walk (of length 6). > > > This is an easy way to let a node stay with a location for a while > > (unless > > > swapping) and to let the neighbors route through it before randomizing > > > again. X=0 corresponds to not randomizing at all. > > > > > > Discussing the results: > > > There seems to be room for running a low-frequent randomization to begin > > > with. For one case (average degree=10) it even seems to perform better > > in > > > some cases with randomization with a quite large period (this surely > > > depends on that randomization can help the algorithm get out of some > > > suboptimal configurations). This does not seem to happen for a larger > > > average degree, perhaps because each randomization will have impact on > > more > > > links (but that is no controlled answer, just speculation at the > > moment). > > > > > > Another note: how quickly the algorithm improves the network from the > > > entirely randomized state is not of foremost interest here, the > > interesting > > > thing is what happens when the network is rather stable from swapping > > for a > > > long period. Therefore its the resulting level (on the right sides of > > the > > > plots) that are important, but the levels seem to have settled around > > some > > > performance (I will rerun the first simulation again to see how pure > > > swapping without no randmization behaves in a longer run) > > > > > > Finally, we dont know if the observed behaviour here will be the same in > > > the current Freenet topology (since the efficiency of the swapping > > > algorithm depends on how much the topology deviates from the Kleinberg > > > model in the first case). Therefore any implementation attempt should be > > > using defensively low periods of randomization. > > > > > > regards, > > > /Vilhelm > > > > _______________________________________________ > > Tech mailing list > > Tech at freenetproject.org > > http://emu.freenetproject.org/cgi-bin/mailman/listinfo/tech > > > > > > > -- > Founder and CEO, Thoof Inc > Email: ian at thoof.com > Office: +1 512 524 8934 x 100 > Cell: +1 512 422 3588 > AIM: ian.clarke at mac.com > Skype: sanity > _______________________________________________ > Tech mailing list > Tech at freenetproject.org > http://emu.freenetproject.org/cgi-bin/mailman/listinfo/tech -------------- next part -------------- A non-text attachment was scrubbed... Name: not available Type: application/pgp-signature Size: 187 bytes Desc: not available URL: <https://emu.freenetproject.org/pipermail/tech/attachments/20070815/0de65120/attachment.pgp>
