I wanted to answer your question here instead of the other thread. IPLC stands for internet private leased circuit. The difference between running public IP and IPLC is that IPLC uses a different signalling usually and is more reliable then pure IP. It goes through lesser hops and is managed all the way. IPLC in Pakistan can be taken from FLAG telecom but it will prove expensive as compared to public IP. So Faheem, IPLC is another form of bandwidth.
Five9 is a good solution and we use it in our center apart from 2BT’s solution. You will need their media gateway ; you can contact my company to help you setup.
Where are you looking to setup the call center ?