If you are ready to deploy IP telephony, and you wonder if your network is ready as well, there are at least three ways to find out. Simply deploying it and hoping it works is probably not the best choice, so here are two better options.
Chapter 14, "Capacity Planning Scenarios," describes a capacity-planning scenario that could also be used for VoIP analysis. The other option is to leverage IP SLA and run specific VoIP operations, ideally at 5-minute intervals for a couple of days. These operations should be initiated at different locations in the network, such as a branch office, the data center, employees' home offices, and so on.
The results of both methods should clearly indicate the network's bottlenecks.