Hello, and welcome to AO

I don't really understand what you are trying to achieve here, so some clarification of yoiur objectives might help?

From what I can see from your diagram, you are looking at the difference between a router with access control list and an external (stand alone) firewall? Well I can tell you that...........the firewall solution is slower because it has to negotiate both the PIX and the router.

Biggest flaw that I can see in your proposed test is the internet cloud................. my connections can vary in a matter of seconds, so I would not consider it to be a reliable metric at all, as you do not have control over all the elements.

Personally I would just place a dumb server at the exit and measure to that..............at least that is a level playing field, which the internet certainly is not.

And why so "accurate"???????????? why would a few milliseconds matter when you have a luser between chair and keyboard?