Future WAN architecture driven by services, traffic volume, and technologytrends

Wide area networks (WANs) today involve protocol and topological hierarchie s. Protocol hierarchy involves Internet protocol (IP) asynchronous transfer mode (ATM) synchronous optical network (SONET) and dense wavelength divisi on multiplexing (DWDM). Self-healing SONET rings provide very fast restorat ion, and DWDM allows the creation of multiple wavelengths ("virtual fibers" ) from a single optical fiber; providing ever-increasing capacity to the SO NET layer. Topological hierarchy involves edge nodes and core nodes for IF: ATM, and SONET: It provides traffic aggregation and statistical multiplexi ng: takes advantage of transport bandwidth and economy of size of packet/ce ll switches, and allows easier operations. A confluence of factors, however , is driving changes in this network architecture. Explosive growth in traf fic volume and emergence of true multiwavelength, multiservice optical netw orks will make flatter (more heavily meshed) service networks supported by an optical core network more economical in the future. In this paper, we di scuss the factors driving this shift in the network architecture, quantify its cost advantage, describe its impact on the requirements for network ele ments comprising the optical transport network (OTN) and the service networ k, and discuss new management/control paradigms as well as opportunities fo r new revenue-generating services resulting from the new architecture.