BA 471 – Telecommunications and Networking Dr. V.T. Raja Oregon State University
Outline Introduction –Analogy with effective human communication Network Design and Topology
Some Basic Characteristics of Effective Human Communication Sender/Receiver Messages (Words) Transmission Media Air/Printed Page Speak same language or have an Interpreter Less noisy room (or) talk loud
Some Basic Characteristics of Telecommunication Networks Source; Destination – Host Signals (Digital/Analog) –Modulation (digital to analog) –Demodulation (analog to digital) –Done by a Modem Transmission Media –Wired/Wireless Communications Protocols/Standards Amplifiers/Repeaters/Internetworking Devices
Wired Transmission Media Coaxial (like cable TV) Twisted Pair –Copper –Shielded and twisted to reduce noise Fiber Optic –Much faster –Able to go longer distances without a repeater –Uses light not electricity –Multi-color lights vastly increases capacity –Expensive
Wireless Transmission Infrared (as in a TV remote) Radio Signals (as in microwave transmissions) Satellites – –GEOS: Geosynchronous Earth Orbiting Satellites – stationary orbit at 22,300 miles above the Earth –LEOS: Low Earth Orbiting Satellites Closer to the Earth and reachable from mobile devices 200-1,000 miles above the Earth Not stationary, goes around the Earth in about 90 minutes LEOS are needed to cover the Earth
Some Basic Characteristics of Telecommunication Networks Source; Destination – Host Signals (Digital/Analog) Transmission Media Communications Protocols/Standards Amplifiers/Repeaters and other Internetworking Devices (e.g., hubs, switches, routers, multiplexers)
Network Design How to support full connectivity? Design the most economic internetwork between “end-user nodes” and an existing WAN Design the most economic internetwork between “end-user nodes” and an existing WAN Usernode WAN
Network Design Find an economic internetworking solution Usernode A direct connection to a WAN backbone node Usernode Connection via multiplexers
Some Network Design Issues Major Cost Components Acquisition and installation costs of a MUX Acquisition and installation costs of a MUX Cost of high bandwidth link between MUX and WAN (Internet) Cost of high bandwidth link between MUX and WAN (Internet) Cost of low bandwidth link between end- user node and MUX Cost of low bandwidth link between end- user node and MUX A Multiplexer (MUX) consolidates several (many?) slow links (local networks or single nodes) and connects them to a fast link (e.g. a WAN such as the Internet). A Multiplexer (MUX) consolidates several (many?) slow links (local networks or single nodes) and connects them to a fast link (e.g. a WAN such as the Internet).
Network Design Management How to design a feasible and economical internetwork? Find an optimal number of MUXs to interconnect all given user nodes to some existing WAN such that... Find an optimal number of MUXs to interconnect all given user nodes to some existing WAN such that... * All user nodes are connected * User communication requirements are satisfied * Capacity constraints on each MUX is not violated * Total internetworking costs are minimized * Topology issues are considered
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Example 3
Some Network Topologies Star topology Star topology Bus topology Bus topology Ring topology Ring topology Mesh topology Mesh topology Physical versus logical topology Physical versus logical topology