On Feb 4, 2008, at 7:24 PM, Michael Rogers wrote: > Matthew Toseland wrote: >> Swapping creates this problem. Or does it? Could you perhaps do >> some simulations of two networks of different sizes weakly linked >> and show whether they get independant location spaces, or whether >> swapping tries to put one of them within the global keyspace for >> the other? > > Here's a quick simulation that shows that two weakly-connected > subnets move into separate regions of the key space. Each subnet has > an ideal Kleinberg topology and starts out uniformly distributed > across the whole key space, and there are also a few random links > between the subnets - this is meant to represent what would happen > if you created a few links between two mature networks, or between a > real network and a Sybil network. > > I couldn't be bothered to do a nice GUI so the output is just a > series of histograms: on each line the key space is divided into 20 > regions, and each column shows the number of nodes from the first > subnet in that region. Initially there are roughly 50 nodes in each > region, but swapping causes the subnets to segregate so that > eventually most regions are almost exclusively occupied by one > subnet or the other. > > It's kind of interesting to compare this with "white flight" in > sociology... > > Cheers, > Michael
Ok. I see it Michael's way now. I'm not sure to what degree this effects our present network, but when graphed out, the individual location movements from this swapping simulator often mirror zothar's previous graph (of location jumping); and while one network is making a hole in the other, the sliding/ compression looks just like what I saw previously as network rotation. This is quite a problem. In fact, this may be the fundamental problem with swapping. Because of this, a sybil network could presently even choose which segment of the keyspace to occupy with very few links. The same network coloring/routing logic *might* be applicable to swapping. That is, to simply confine swaps to the network they came from. I'm not aware of another way to both secure sybil nets from invasion and keep major keyspaces separate. Unfortunately it has the obvious problem of a dependency feedback loop: (1) swaps are fundamental to routing, (2) routing is required for my auth-ping idea, (3) these auth pings are required for secured network-id coloring, (4) then... could we use the network id's to modify swapping??? It seems like the network-id idea would have to be changed to be a little more relaxed; either by not effecting swapping until we have computed the assigned network-ids (fall-open while in transition), or by simply accepting (for the moment) the most common network id from our peer set (rather than strictly random id on startup). My question is, *if* such an idea is considered valid and in such a case how could we be assured that us labeling and isolating a subnet is not what *keeps* it labeled as a subnet because it's routing is messed up for lack of swapping? I guess that would require all the bordering nodes to consider that simultaneously, which would be a rare and unstable condition in a well connected network. -- Robert Hailey
