The Internet has had phenomenal success in the past 20 years, growing from a small research network to a global network that we use in a daily basis. The Internet is logically composed of end hosts interconnected by links and routers. When a host wants to communicate with other hosts, it uses the Internet Protocol (IP) to place information in packets, which are then sent to the nearest router. The router stores, then forwards, packets to the next hop, and through hop-by-hop routing, packets find their way to the desired destination. In other words, end hosts communicate through packet switching. With this communication technique, link bandwidth is shared among all information flows, and so these flows are statistically multiplexed on the link. The resulting service is best effort, in the sense that there are no deterministic guarantees.
Another switching technique that is widely used in communication networks, especially in the phone system, is circuit switching. When a terminal wants to communicate with another terminal, this technique creates a fixed-bandwidth channel, called a circuit, between the source and the destination. This circuit is reserved exclusively for a particular information flow, and no other flow can use it. Consequently, flows are isolated from each other, and thus their environment is well controlled. This Thesis studies how the Internet could benefit from more circuit switching than is prevalent today.