Traditional digital telephone networks utilize time-division-multiplex circuit switching to share physical network links among multiple telephone connections. In addition, circuit switching, in the form of re-arrangable time-division-multiplexed paths, is commonly utilized to provide dedicated (but re-arrangable via network management functionality) capacity between pairs of router ports in packet networks. When one employs byte-by-byte time division multiplexing (e.g., as in SONET), to create circuit switched paths between pairs of router ports, one can achieve the benefits of deterministic (as opposed to statistical) sharing of the capacity of the fibers or wavelengths that make up the physical interconnection fabric of a network. But this comes at the expense of deploying and operating both conventional byte-by-byte time division multiplexing equipment, and packet switching equipment; i.e., two, overlaid networks.
© 2001 Optical Society of AmericaPDF Article