on of the long distance telephone business led to newer approaches to transmission and switching such as SONET/SDH, ATM, and other packet- or cell-based technologies. The impact of the Internet Society, in particular the Internet Engin- eering Task Force (IETF), on global communications standards has been significant to say the least. An example of the kind of innovation that is likely to survive and grow well in to the future is embodied in a technique called multi-protocol label switching (MPLS) sometimes truncated to simply label switching. MPLS is a com- bination of techniques derived from IP and ATM switching and protocols. Other Emerging Switching and Routing Technologies ASON (Automatic Switched Optical Network), GMPLS (Generalized Multi-Protocol Label Switching), and RPR (Resilient Packet Ring) are in active standards development and various stages of maturity at the time of this writing. A full description of each is far beyond the scope of this book. However, a brief description of each is note- worthy. ASON and GMPLS are often seen as a source of contention and competition between ITU and IETF standards development groups, but this is more an impression gained from reading press reports. ASON is a new architecture that will leverage existing SONET/SDH architecture by adding optical switching and control protocols. The motivation for ITU members and their suppliers lies mainly in reduction of capital investment at the core and operations cost associated with provisioning, while at the same time enabling paying customers to use the network in new and innovative ways. Recognize that this work is heavily biased by ITU due process in which the focus is working from well-defined detail requirements for architecture. The basic approach is to agree on the architecture and then work out a set of underlying control protocols, and don't forget that the background and experience of the developers is heavily influenced by years of operating TDM networks controlled by CCS7/SS7 and DTMF signaling. PRACTICAL IP AND TE