IP-Centrex & Multi-Tenant PBX Systems: Overview

IP-Centrex services is a term for hosted PBX services. That is to say providing businesses with PBX services in the cloud, rather installing expensive PBX hardware on site.


IP-Centrex Architecture


IP-Centrex is not to be confused with multi-tenant PBX systems, which are installed on site for hosted office suites to allow landlords to bill their tenants for calls.


IP-Centrex Architecture

IP-Centrex gives businesses the ability to quickly scale up or scale down their requirements, typically paying on a per extension basis. The business plugs an IP phone into their network, this connects to the PBX in the cloud, and calls can be made.

There are two main techniques to IP-Centrex Systems, and A2Billing is compatible with either.


Each PBX is virtualised on its own virtual operating system, an a range of virtualisation technologies can be used, including Xen, OpenVZ, VMWare, and many others.

The advantage is that each PBX system is isolated from every other PBX. The disadvantage is that a Public fixed IP address is required for each individual PBX, unless either VPN, reverse proxies and Session Border Controllers are employed.

Single Server System

A single server with multi-tenant PBX capabilities can be installed. The customers are logically isolated from each other, and to integrate with A2Billing, a separate trunk has to be made for each customer.

The advantage of this approach is that the hardware is better utilised, as there is only one telephony engine, but the disadvantage is that there are not so many multi-tenant PBX system available as there are single tenant systems.

Star2Billing can provide a range of Multi-tenant and IP-Centrex systems integrated with A2Billing for termination, origination and VoIP Billing. Please contact us for more details.