NAT usage at large companies (was: Re: [e2e] Number of persistent connections per HTTP server?)

[John Heidemann]

On Mon, 14 Oct 2002 22:42:33 PDT, Vadim Antonov wrote: 
>On Mon, 14 Oct 2002, Joe Touch wrote:
>> Since the NAT likely shares the majority of the path that determines RTT 
>> and bandwidth, it won't hurt sharing.
>
>Very often, this is not the case.  What you have in a typical organization
>is single NAT/firewall, and a VPN behind it.  Quite often parts of that
>VPN are on different continents :)

Can folks offer some more details about how prevalent this kind of
NAT deployment is?

My assumption was that NAT is primarily used by homes/small
organizations that are geographically co-located.

I would have assumed that organizations large enough to have large
multiple, geographically distributed locations (i.e., more than just a
few people dialing in) would use application-level gateways for most
of their traffic (especially for web traffic).  They would do this to
take advantage of caching/conservation of their upstream bandwidth, or
because they are multi-homed and so can't easily run a single NAT,
etc.  (Insert your own more inflamatory statements about NAT here.)

Can you suggest (or imply :-) what large organizations would deploy
NATs as their primary means of gatewaying traffic to the Internet?

   -John Heidemann