# Shortest path to the world

Leo Bicknell bicknell at ufp.org
Thu Jul 16 03:06:13 UTC 2009

```In a message written on Wed, Jul 15, 2009 at 10:39:05PM -0400, Sean Donelan wrote:
> As I said in the original message, every nation in the world.  Or more
> specifically the largest number of IP endpoints reachable in the most
> nations from the locations chosen.
>
> A = the few locations you pick
> B = every other IP endpoint reachable from those locations
>
> If every point B in the world is inside your network, awesome.  But
> highly unlikely.

I will assert that for all the small numbers (N < 5) the answers
are non-overlapping sets.

That is, not that these are the acual sites, N = 1 may be New York,
N = 2 may be Amsterdam and LA, N = 3 may be Hong Kong, Chicago,
Frankfurt, and so on.

> More than likely to maximize reachability, minimize latency, the
> highest goodput, and most availability will require some combination
> starting locations and ISPs.

Reachability, latency, and goodput can not be all minimized at the
same time.  There are more than one way to create a synthetic metric
combining the three, so it's quite unclear how to answer your
question.

> True, optimization and constraints solving is easier with fewer variables.
> There are also researchers that seem to spend lots of time measuring
> the Internet and collecting data for all sorts of reasons.  When creating
> graphs of the Internet, one of the basic problems every mapper has to
> solve is deciding where are the "centers" of the map.

95% of the mapping efforts look only at reachability, and then from
incomplete data.  Another 4% look at it from latency.  1% look at
it from goodput.  I have never seen a data set that related two,
much less all three in any meaningful way.

Quite frankly, your question reminds me a bit of the geography
question "where is the center of the US".
http://en.wikipedia.org/wiki/Geographic_center_of_the_contiguous_United_States
While nifty trivia, it acutally has no useful value for well,
anything.  If it did, there would be more there than a small monument.

If you're going to deploy something, in addition to the criteria
you have listed you will have to consider cost and availability of
time in doing business in multiple jurisdictions, getting people
to these locations to set stuff up, cost and availability of bandwidth
between sites, management overhead of what you're going to deploy,
and so on.

One last wrench in your works.  It depends on how much traffic you
want to do.  If you want to move 50Mbps total, the answer is entirely
different than if you want to move 500Gbps.  Goodput holds until
links fill, and which point it falls off.  Plenty of video sites have
great goodput from their set of locations until a flashmob (say, Michael
Jackson) comes along and then the goodput from the same set of sites
crashes and burns.

So, you have a question that probably can't be answered, but if it could
the answer doesn't matter, and even if it did, the Internet is dynamic
so it will all be different tomorrow.

--
Leo Bicknell - bicknell at ufp.org - CCIE 3440
PGP keys at http://www.ufp.org/~bicknell/
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