This Chapter has discussed how to monitor user flows to predict when more bandwidth is needed between boundary routers of a circuit-switched cloud in the Internet. It has also developed a simple model that can be used to estimate safeguard bands that compensate for slow circuit-creation mechanisms.
The most important recommendation of this chapter is that the signaling used to establish a circuit should be as fast as possible. Otherwise, the safeguard band becomes very large. An alternative reading of this recommendation is that the establishment of a circuit should be done simultaneously on all nodes along the path, without having to wait for any confirmation from the upstream or downstream nodes. Moreover, slow crossconnect technologies (such as MEMS mirrors) should only be used if they can provide a very large switching capacity at a low cost, such that it can accommodate the additional safeguard band.