UN Mission: Satellite links & VoIP

5 locations, geostationary satellite links
600ms latency! Full mesh network, 4 transmitters

Linux IP^3 machines for TCP/IP trickery, 'IPMAX'
VoIP, HTTP & SMTP all over a single 128kbit connection

Requirements:
As many phonecalls as can fit
Mail should come in speedily
Webbrowsing should work 
Exchange Webmail in Brussels