5Networking Fundamentals Network Operating System (NOS)Two parts:System software that runs on the serverClient software on each workstationExamplesBanyan VinesNovell NetWareMicrosoft LAN ManagerLANtastic
6Networking Fundamentals Transmission MediaThe pathway to send data and information between two or more entities on a networkBandwidth: transmission capacityAttenuation: weakening of a signal over distanceEMI: electromagnetic interference
11Networking Fundamentals Wireless MediaInfrared line of sightHigh-frequency radioPager – one way wirelessCellular phone – two way wirelessWireless LANsMicrowaveTerrestrialSatellite
12Network Software and Hardware Media access controlRules that govern how a workstation gains access to the networkDistributed access controlToken passingRandom access control“Listens” for network traffic
13Network Software and Hardware Network topologiesStar networkRing networkBus network
15A star network topology Use: This topology is useful for applications where processing must be centralized and some can be performed locally.Advantages:Easy to lay out and modify.It is easy to diagnose problems at individual workstations.Problems:Costly, it requires the largest amount if cabling.Since all communication pass through the central computer, the communications in the network will stop if the host/hub computer stops functioning.
17A ring network topology Use: This topology is useful in LANs.Advantages:It does not rely on central host.The connecting wire, cable, or optical fiber forms a closed loop. Data are passed along the ring from one computer to another and always flow in one direction. The message is regenerated and passed to the next computer if it is not for the previous computer. This regeneration process enables ring networks to cover much larger distances than star or bus networks.Disadvantages:A failure of any node on the ring network can cause complete network failure.It is difficult to modify and reconfigure the network.
19A bus network topology Use: This topology is useful in LANs. Advantages:It does not rely on central host.This network can still function if one of the computers malfunctions.Other advantages: easy to wire, quick response, less expensive.Disadvantages:The main disadvantage is bad connection to the cable can bring down the entire network. Another problem: collision occurs when 2 nodes send messages simultaneously.
20Network Software and Hardware Protocols: Set of rules ( format of transmitting data, error checking method, data compression technique)OSI model – open systems interconnectionEthernetTCP/IP
23Network Software and Hardware Connectivity hardwareTransmission Media Connectors: T-connector for coax cable and RJ-45 connectors for twisted pairNetwork interface card (NIC)ModemsRepeatersHubsBridgesMultiplexersRoutersBroutersChannel service units (CSU): buffer between a LAN and a WANGateway