chapter  8
4 Pages


Over the course of their respective lifespan, the public switched telephone network (PSTN) and the Internet have evolved in divergent ways. The PSTN has been characterized by centralized control of network resources where the intelligence required to process the information resides in the core of the network. The Internet espoused a view that was completely opposite. The network itself was simply considered a transport to move information in the form of bits toward the edges, where more powerful and intelligent machines operated on these bits. Not surprisingly, their respective service architectures reflect this division in philosophy.