When building a private network, engineers are faced with many more choices, options, and challenges.
Private networks tend to be more expensive to build and manage as well.
Many carriers are now offering ATM service for a minor premium over basic frame relay service. Yet the options available when going on your own are pretty compelling. By building out your own circuits and switches, you'll maintain better control over the network itself and have more opportunity for growth in the future. Technologies such as Switched Virtual Circuits and PNNI have been very slow to appear in public network services, although they offer distinct benefits to the customer. Note that it is also possible to tunnel SVC traffic signaling across a PVC-based public network and realize the cost benefits of public ATM carrier transport services and the power of SVCs for real time traffic.