Telecommunications and Networking Dr. V.T. Raja Oregon State University Summer 2007

Outline Introduction –Why care about telecom/networking? Why should non-IT business students learn basics about telecom/networking? Some basics about Telecom/Networking –Analogy with effective human communication

Why telecom/networking? Some Reasons

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

Wired Transmission Media Twisted Pair Cables Coaxial Cables (Cable TV) Fiber Optic Cables Wavelength Division Multiplexing

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 –

Communication Protocols Speak same language or have an interpreter –HTTP (Hyper Text Transfer Protocol) –SMTP (Simple Mail Transfer Protocol) –TCP (Transmission Control Protocol) –IP (Internet Protocol) –Ethernet

Communication Protocols (Continued) Ethernet –Media Access Control (Traffic Cop – Who has access to transmission media and when? How to handle/resolve collisions?) –Error Detection/Correction –Message Delineation (Identifying beginning and ending of packets – framing) TCP –Packetizing (Breaking messages into smaller packets and reassembling packets in the correct order) –Keeping track of packet #s

Communication Protocols (Continued) IP –Addressing (DHCP and DNS) –Routing Tracert Tracert

Some Internetworking Devices Routers, hubs, switches –routers use routing rules to forward packets to the next appropriate destination –hubs forward all packets on all connected wires –switches keep track of which computer is on each line and send packets only to the desired destination

Routers This is how packets find their way around the Internet A Router B

Hubs vs. Switches: Switching increases performance, security, and cost A B Oh, Good! B? That’s not for me, I’ll ignore it What’s this? I’m not B B? So what? Nothing here Hub Switch

Network Design How to support full connectivity? Design the most economic internetwork between “end-user nodes” and an existing WAN Usernode WAN

Network Design (Continued) 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 Cost of high bandwidth link between MUX and WAN (Internet) Cost of low bandwidth link between end-user node and MUX A Multiplexer (MUX) consolidates network traffic from several users on slower links and connects them to a fast link (e.g. a WAN such as the Internet).

Some Network Design Issues (Continued) 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

Example 1

Example 2

Example 3