MS Terminal Server Bandwidth Requirements (WAN)

I’m trying to get some information on what sort of bandwidth I would need to connect 15 Thin Client machines to a terminal server over the internet.

We have a remote site which needs 15 machines but with a limited budget a leased line would be imposable. I was thinking perhaps using RDP over the net to connect these but need to know what sort of bandwidth I would need so there ‘usable’. I don’t think they’re going to do anything to graphical on them mainly just Office, email and a bit of web browsing (normal student activates).

we based our ica bandwidth utilisation on 20kb/s per user/device. I doubt rdp would be much more

That sounds very low I wouldn't have though I could get 15 connections out of a standard ADSL (400kbs down speed).

ica and rdp traffic is isn't constant, it's bursty traffic and if you can QOS or COS it is worth prioritising this traffic. It's difficult to give a precise bandwidth answer because it depends on what the users are doing.
I've run ica over a dialup connection and had no problems whatsoever (logging in to school via citrix and using the internet is quicker than using internet over dialup!), I didn't think rdp was much worse, but i could be wrong.

The QOS will be out of my hands once it leaves the router but locally it will be a nice fast LAN with only local printers.

Thanks for your input CyberNerd I’m guessing it going to be a trail and see how they get on.

There's a little bit of info at Windows IT Pro - How many concurrent RDP connections are possible which suggests RDP will probably take about 30kbps, depending upon the features you enable.

RDP uses much more bandwidth than Citrix, Citrix is specially optimized and due to an agreement between MS and Citrix MS did not develop their RDP option much until recently. The later versions of RDP are better on bandwidth so you could benifit by using Windows 2008 as you terminal server and fully up to date RDP client software if bandwidth is an issue.