N+? redundancy

[Michael.Dillon () radianz com]

> And I agree re: the building entrance issue and later choke points.
> Anyone recall the time several years ago that most of the Valley was
> isolated? One route was across the ?Bay? Bridge; it was down for
> planned maintenance when backhoe fade struck around San Jose.
> How many paths is enough?

In my opinion, the following rule of thumb is reasonable.

1 path is enough for a site/enterprise that shuts 
down its services evenings and weekends.

2 paths is enough for a site/enterprise that provides
a 24 hour, 7 day per week service.

3 paths is enough for a population center with under
a million inhabitants.

5 paths is enough for a population center with over
a million inhabitants.

And a very few population centers such as New York,
London, Tokyo, and Cheyenne Mountain should probably
have more than 5 paths.

--Michael Dillon