There are some IVR application which can be really large, catering to millions of daily callers. For example, any utility service like Gas Cylinder Booking System, Customer Care for nationalised banks etc. Normally, these services are controlled by one large organization centrally via huge network of branch offices, distributor/dealer network across length and breadth of a country.
So, designing and implementing a self service IVR for booking of gas cylinder may pose a big challenge while deciding a solution architecture.
For a large country like India, self service Gas Booking IVR is quite a challenge.
For example :-
It might be difficult to decide upon either using centralised IVR system catering to whole country or distributed or separate IVR system at different zones ( North, South East or West) might itself be quite difficult. While both architecture have advantages or disadvantages. Centralised IVR system will offer better utilisation of resources as well as maintenance, but distributed IVR systems may offer more uptime. Maintaining IVR systems in large geographical area may require big human resources.