System architecture determines the success of converged VoIP telephony in terms of cost savings, system reliability and quality. Clearly, the ideal solution is a single network infrastructure to support all your communication needs. However, when considering this, the costs need to be weighed against the returns. You also need to explore the possibility of setting up a converged solution on your existing infrastructure.
Cost versus Savings: The infrastructure for TDM is expensive, and if you've invested in it, it’s hard to justify the cost of switching to a VoIP solution. Especially if your logic is simply, "this is where the future is headed". Companies need to consider the cost of installing infrastructure to support VoIP, which is about equal to the cost of a TDM system, and its potential returns. One alternative to VoIP is TDM over IP (TDMoIP), a gateway that allows connection to Internet broadband over your existing TDM infrastructure. This will enable businesses to save money on pricey wideband lease lines, gaining access to lower-priced IP telephony.
VoIP: If your business is only now purchasing its advanced telephony infrastructure, VoIP-based systems may be a sound investment. While the savings at the building stage may be minor, the potential for running advanced applications in the future opens up new opportunities for cost savings and productivity jumps. The recurring savings of switching to Internet telephony, in terms of lower call costs, can also not be ignored.
Freedom and Flexibility: Suppliers try to bundle their product, services and hardware to lock buyers into their IP-based PBX solution. Some vendors will offer mid-range telephony systems, only to charge heavily for additional specialised handsets. Ensure that you know the cost of adding lines, hardware and so on. Ideally, pick a solution that allows every component to be independent and replaceable by a competitor’s component. This will let you take advantage of new developments and it provides flexibility and can save money
Reliability and Quality: Legacy systems used dedicated hardware and software to ensure system reliability and voice quality. While expensive, they were completely dependable. The replacement system, whether VoIP-based or TDM-based, must deliver the same level of voice quality and reliability. Voice communications require a higher level of reliability than data and this implies that you need more robust systems, which ensure lowered cost but no compromise in any other aspect.