They then analyze how the remaining major cost components, switching and transmission for both types of networks and interconnecting with the switched circuit network for the IP-based networks, change with the change in technology.
Hundreds of thousands of switches and circuit breakers must be operated manually, and the main transmission lines have little instrumentation to monitor the second-by-second flow of electricity from unpredictable new sources like windmills.
Their conclusion is that the switching and transmission costs for IP-based telephone networks are much lower than for switched circuit telephone networks.