Cloud and managed services are driving the growth of multi-tenant platform for PBX and Contact Centers. The heart of such a platform is the underlying telephony engine. Asterisk is one of most versatile and powerful telephony engine available today. In reality it is a complete communications platform packing the functionality of a soft-switch, a protocol gateway, a media server, and a VoIP gateway. Above all, it is a full function PBX with a very large ecosystem supporting application development on it.
Large multi-tenant installations will require to scale to multiple Asterisk servers to deliver the required concurrent call capacity. This is usually provided by an external ACD (automatic call distribution) software that uses Asterisk servers as the underlying media server for voice. Such a call center ACD will manage the call routing and distribution by exercising control over the individual Asterisk servers through the Asterisk Manager Interface (AMI). The aspect of multi-tenancy is a separate matter altogether. This is the function of the call center and PBX management software that handles the setup of the installation. The multi-tenant call center ACD and PBX software allows separation of the tenants without an actual physical separation. Multi-tenant PBX should also allow branding at tenant level, to provide a personalized touch.