North American Network Operators Group

Date Prev | Date Next | Date Index | Thread Index | Author Index | Historical

## Re: Points of Failure (was Re: National infrastructure asset)

• From: Peter van Dijk
• Date: Tue Sep 25 16:26:16 2001

```On Tue, Sep 25, 2001 at 04:04:38PM -0400, batz wrote:
[snip]
> Is there a geometric method of measuring the 'meshedness' of a
> given set? If you take all the as-paths from a sampling of
> peers across the Internet, and show the relative density of
> where the respective paths converge, you can get a good picture
> of who's transiting the most routes.

The mathematical term 'connectivity' measures the least number of
vertices that has to be destroyed to stop a network from being fully
connected.

Any network that contains a SPoF (even if it only causes one small bit
to go lost) has a connectivity of '1'. Any network that you need to
hit at least 2 vertices (routers and switches would be vertices, lines
would be edges) has a connectivity of '2'.

There are very nice mathematical methods for determining the
connectivity and connectionness of a graph (network).

I can recommend Skiena's "The algorithm design manual" for anybody
interested. It is supposedly available online in HTML (I bought the