Network integrity and non-random removal of nodes

William Waites ww at
Thu Nov 21 19:56:10 UTC 2002

>>> "Sean" ==   <sgorman1 at> 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? 


    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?


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