How can I test my application's network footprint?

I have no experience in network administration, so apologies if this is a clumsy question.

I have a .NET application to deploy locally at my client's site. They have the hardware to do this, but have concerns about the network capability.

Infrastructure

• My client has a开发者_StackOverflow 2mb upload/download network connection.
• They currently serve webmail to 260 users.

Web app

• The web application will be used by ~200 users
• Each user will probably log in a couple of times a week, no spike time of day.
• An average usage would probably involve the download/upload of about 5 fairly small form pages (5-15 fields)

My gut feel is that this is very low usage, and shouldn't cause much impact on their current setup. However, I would like to verify this if possible.

Generate typical workload and run sniffer like tcpdump, writing raw packets to dump file. At the end of the day you can examine dump's contents to see how much of bandwidth your application utilized.
Sample command-line:

tcpdump -w dump.log port PORT_OF_YOUR_APPLICATION_HERE

There are few ports of tcpdump to windows platform.