This chapter has focused on how the existing IP infrastructure can incorporate fast, simple (and perhaps optical) circuit switches. Several approaches to this already exist, but I have proposed a technique called TCP Switching in which each application flow (be an individual TCP connection or other types of flows) triggers its own end-to-end circuit creation across a circuit-switched core. Based on IP Switching, TCP Switching incorporates modified circuit switches that use existing IP routing protocols to establish circuits. Routing occurs hop by hop, and circuit maintenance uses soft state; i.e., it is removed through an inactivity timeout. TCP Switching exploits the fact that our usage of the Internet is very connection-oriented and has end-to-end reliability to provide lightweight signaling mechanisms for circuit management. Finally, this chapter has showed how despite the fine granularity of its circuits, TCP Switching is implementable with simple hardware support, and so it is capable of providing the advantages of circuit switching to the Internet. TCP Switching is an extreme approach that shows how one can integrate circuit switching in the core of the existing Internet while extracting the benefits of circuit switching that were listed in Chapters 1, 2 and 3: higher switching capacity, robustness, simple QoS and end-user response time similar to that of packet switching.