[53719] in North American Network Operators' Group
Re: Network integrity and non-random removal of nodes
daemon@ATHENA.MIT.EDU (William Waites)
Thu Nov 21 14:56:41 2002
To: <sgorman1@gmu.edu>
Cc: nanog@merit.edu
From: William Waites <ww@styx.org>
Date: 21 Nov 2002 14:56:10 -0500
In-Reply-To: <4d9b6f4d8284.4d82844d9b6f@gmu.edu>
Errors-To: owner-nanog-outgoing@merit.edu
>>> "Sean" == <sgorman1@gmu.edu> writes:
>> 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
