I understand that the servers have a 10/100 network card...

but you are paying a 3rd party vendor for your internet connection. they are giving you a connection that has a finite speed. Who is your vendor? at what speed are you connecting? this is relevant.

using your diagram and adding points of reference

Server 1 == 10/100 -- internet company --- lots of hops -- internet company --- 10/100 == Server 2

Your VPN will never be 100Mbps, unless you are using the internet2 connections that some colleges have.

If you are not sure, contact your accounting department and ask them the name of the company that is paid to give you your internet at your place of business.

Your internet company provides you with bandwith. this is the amount of data that can be sent / received at any point in time usually represented in down / up (down TO you and up FROM you [example, some DSL will give you 1.5Mb/386kb which is 1.5Mb you can download from the internet but only 386kb with which you can SEND to another server - internet connection]).

We keep asking this information because if you have a T-1 line (highly recommended as it is usually has a static IP address) then you set it up one way, and if you have residental cable (usually has DHCP addresses) then you would need to set it up a different way.