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NETWORK FUNDAMENTALS. NETWORK FUNDAMENTALS. Network Topology Network Cable OSI Model Network Hardware. Network topology. Bus Topology Ring Topology Star Topology Tree Topology Mash Topology. Bus Topologie. Uses a common backbone to connect all the network devices
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NETWORK FUNDAMENTALS • Network Topology • Network Cable • OSI Model • Network Hardware
Network topology • Bus Topology • Ring Topology • Star Topology • Tree Topology • Mash Topology
Bus Topologie • Uses a common backbone to connect all the network devices • A single cable(backbone) operates as the shared communication medium for all the connected devices • For example: 10Base2 10Base5 Backbone
Bus Topology • Advantages • computers can be detached without effect other computers • its cheap • only a single cable is used • Disadvantages • if the backbone Cable is broken, the entire network go down • all the traffic is send to every station • bad performance if more then 15 computers are added to the network • It is slower then other topologies • Cable must be terminated
Ring Topology • each Computer connects to exactly two other Computers • all the communication messages travel in the same direction (clockwise, anti clockwise) • each node handle every packet • example: Token Ring
Ring Topology • Advantages • no kollision in the network • all stations work as repeater • Large networks possible • Disadvantages • if one computer or cable fails the network will breakdown • hard to Implement • Expensive components
Star Topology • one of the most common computer network topologies • all computers are connected with a point to point connection to a central device • examples: telephone networks, modern ethernet Networks Central Device (Switch,Hub)
Star Topology • Advantages • if a cable is broken only the computer wich is connected to the cable can no longer communicate with the network • if a computer fails then the other computers are not affected • easy extensible • high transmission rate • Disadvantages • if the central device fails the whole network will brakdown • Network size is limited by the number of ports on the central device
Tree Topology • central 'root' node is connected to one or more other nodes that are one level lower in the hierarchy (second level) • each second level node will also have one or more other nodes connected to it • the nodes are connected via a point to point link Root node Second level node
Tree Topology • Advantages • if a computer fails then the other computers are not affected • Disadvantages • if a node fails all computer wich are connected to the node are no longer reachable • If the rootnode fails the whole network is down
Mash Topology • Every computer will be connected to one ore more other computers. • If every computer is connected to every other computer, the network will be called “complete meshed network“ • Example: internet, big networks Complete mashed network
Mash Topology • Advantages • Is the best topology, because it is the most secured one • if one computer faill the communication is still possible because the data will be redirected • Disadvantages • very hard to install • much cable is necessary • expensive
Network Cable • Thicknet (Yellow Cable) • BNC (cheapernet) • Twisted Pair
Thicknet (Yellow Cable) • is a RG-8/U coaxial cable • It is used in 10Base5 networks • to connect a network device a mau is needed • the cable ends must be terminated • maximum length is 500 metres • transmission speed is 10Mbit/s • maximum count of computer is 100 • Expensive Yellow Cable MAU Medium Attachment unit
Thinet (cheapernet) • is a RG-58 coaxial cable • It is used in 10Base2 networks • the cable ends must be terminated • maximum length is 185 metres • transmission speed is 10Mbit/s • maximum count of computer is 30 • Network devices is connected using a t-connecter Terminator T-Connector
Twisted Pair • It is used in modern networks • Maximum length is 100Metre • Transmission speed is 10-10000Mbit/s • There are serveral Standards for this cable called Categories (Cat-5,Cat-6) • A typical cable contains 4 pairs • A pair consist of 2 twisted conductors Pair Plastic Jacket
Twisted Pair Standards
OSI Model • Is a abbrevation of Open System Interconnection model • defines a networking framework for implementing protocols in seven layers • The upper layer represents software that implements network services like encryotion • The lower layer implements hardware-oriented functions like routing, addressing,
Nezwork Hardware • Hub • Switch
Hub • work on layer 1 of the OSI model • Do not read any of the data passing trough them • Broadcast the recivied packets to all network devices • 3 types of hubs • passive Hubs con only send and recieve packets • active Hubs are passive hubs wich amplify the signals • Intelligent Hubs add extra functions like monitoring to an active hub
Switch • do the same as hubs but have more intelligence • Can read the data packets to determine the source and destination address • The packets will only send to the device which have the same destination adress as the packet • 2 types pf switches • Unmanaged switches: have no configuration interface,no monitoring and are cheap • Managed switches: have a configuration interface and provide functions like monitoring • Switch work on serveral Layer