Hmm - not sure on who owns the trees, but if anyone does know it would be very useful. Most of the work I've read say the connection distribution follows a power law, and is why I did not think it would follow a linear pattern, but just guess work on my part. There has been some work at BU that says all the power law stuff is just sampling bias inherent in traceroute type of data aquisition. In which case vulnerbility might not be as dire as some of the early reports. How to get an accurate topology is the real big problem, but no need to reopen the private sector vs government vs academia debate. ----- Original Message ----- From: William Waites <ww@styx.org> Date: Thursday, November 21, 2002 7:56 pm Subject: Re: Network integrity and non-random removal of nodes

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"Sean" == <sgorman1@gmu.edu> writes:

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The supposition would be that the remaining nodes are evenly distributed around the core so the percentage of nodes outside of the core without connectivity should be roughly the same as the percentage of nodes removed from the core. At least until the core goes non-linear...

Sean> Is that the supposition stated in the paper?

No.

Sean> The reason being it contradicts quite a bit of similar Sean> research. Nodes inside and outside of the core do not Sean> typically disconnect at the same rate.

References? Note that I posited that the rate was proportional, not the same.

Sean> The nodes outside of the core on the other hand are much Sean> more sparsely connected. 55% of them are trees meaning that Sean> they only have one connection. There is no back up link, so Sean> if their big hub node goes down they are out of commission.

That's more or less what I said. If the trees are evenly distributed around the core, and you take away 2% of the core, you can expect 2% of the trees to disappear too. Of course 2% of the trees is a much larger number of nodes than 2% of the core.

Sean> Hence you could have large numbers of nodes outside the core Sean> disconencted before you would see any effect inside the Sean> core. By the time the core goes non-linear the periphery is Sean> gonna be long gone and disconnected.

True iff the links to the periphery are not evenly distributed across the core, which is my, perhaps faulty, underlying assumption. Does UUNet still own most of the trees?

-w