4 Ethernet Networks 4.1 INTRODUCTION The popularity of Web entertainment, E-commerce, and distance learning, and the concurrent demand for ready access to Web applications in the local networking environment, contribute to the widespread implementation of Ethernet communica- tions networks. A flexible, reliable, scalable, and dependable technology, the Ethernet technology suite sustains intranet, extranet, and Internet connectivity in LAN (Local Area Network) environments and interoperates with wireline and wireless solutions. The Ethernet technology suite is defined by a series of specifications and sup- plements associated with the IEEE (Institute of Electrical and Electronics Engineers) 802.3 family of LAN standards. An Ethernet LAN supports operations in a delimited geographic area such as a classroom, a multistory office building, a factory, or a cluster of buildings on a university campus, and enables information exchange and shared workgroup applications over a common communications medium. The mul- tiservice Ethernet platform interworks with technologies that include Frame Relay (FR), FDDI (Fiber Data Distributed Interface), Fibre Channel (FC), DSL (Digital Subscriber Line), cable modem, WDM (Wavelength Division Multiplexing), and DWDM (Dense WDM).