Asterisk PBX in Nigeria

Hi all, It has been a long time since I had published any item on this blog. There have just been distractions but I am back now. The period of absence does not mean that nothing has been happening in the IP PBX world or that I have not been doing things. I will share with you a scenario where I was involved in the design of a voice network that spans Nigeria and Ghana. This scenario will make us understand practical situations where we can use an IP PBX and how we can configure the PBX to achieve so much. Scenario : An international organisation requires Asterisk PBX in Lagos, Nigeria and Accra, Ghana offices.  The organisation has a VPN link in place between the offices in the two countries. As such, a computer in Nigeria can ping an IP in Ghana and vice versa. Requirement :  The PBX should do the following: Users in Lagos should dial the extension number of the Accra users directly without a leading number and vice versa. The users in both countries to make