# Network integrity and non-random removal of nodes

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...

Is that the supposition stated in the paper? The reason being it
contradicts quite a bit of similar research. Nodes inside and outside
of the core do not typically disconnect at the same rate. Think of it
this way, if a big well connected node goes down the other big conencted
nodes in the core are likely to have an alternate connection to
compensate for the link loss. Average distance might go up a little
bit, but that is about it. The nodes outside of the core on the other
hand are much more sparsely connected. 55% of them are trees meaning
that they only have one connection. There is no back up link, so if
their big hub node goes down they are out of commission. Hence you
could have large numbers of nodes outside the core disconencted before
you would see any effect inside the core. By the time the core goes
non-linear the periphery is gonna be long gone and disconnected.

"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...

> Is that the supposition stated in the paper?

No.

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

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

> The nodes outside of the core on the other hand are much
> more sparsely connected. 55% of them are trees meaning that
> they only have one connection. There is no back up link, so
> 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.

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