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Learn about the different physical topologies in networking such as mesh, star, bus, and ring, their advantages, disadvantages, applications, and connecting devices. Understand how network layout affects connectivity and efficiency.
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Physical Topologies • It refers to the way in which a • network is laid out physically • It is the geometric representation of relationship of all links and linking • devices (usually called as nodes) • connected to one another -K. M. THANVI
Types There are four basic types of network topologies Mesh topology Star topology Bus topology Ring topology
Mesh Topology • Every device has a dedicated point to point link to every other device • A fully connected mesh network has n(n-1)/2 physical channels to link n devices and to accommodate this links each device require (n-1) I/O ports
Advantages • Dedicated link • Robust • Privacy and security • Fault identification and isolation Disadvantages • Large amount of cabling and i/o ports are required • Installation and reconnection is difficult • Sheer bulk of wiring can be more than available space • Hardware required can be expensive Applications • telephone regional office • Wide area network
Star Topology -Each device has a point to point link only to the central controller , usually called as hub -Controller act as ‘Exchange’ -When device 1 wants to send data to device 2; First sends the data to hub. Which then relays the data to the other connected device.
Advantages • less expensive than mesh • easy installation and reconfiguration • Robustness • Fault identification and isolation Disadvantages • Though cabling required is less compared to mesh , but still more cables are required as each node should be connected to central hub. • If hub fails , all attached nodes are disabled • expensive Applications • LAN and High speed LAN
Bus Topology • -Mesh and star are point to point whereas bus is point to multipoint • In this one long cable act as a backbone cable to link all devices on network • nodes are connected ton bus cable by drop lines and taps • DROP LINE: Connection running between device and main cable • TAP : A tap is connector that either splices into main cable or punctures the sheathing of cable to create a contact with metallic core
Figure shows different nodes Connected with bus topology
Advantages • ease of installation • less cabling • less expensive Disadvantages • Fault isolation and reconnection is difficult • Signal reflection at taps cause degradation • Fault or break in the bus cable stops all transmission Applications • most computer motherboard
Ring Topology -point to point connection only with the devices on the either side -a signal is passed along the ring from device in one direction until it reaches the destination - It make use of token ring technology
Figure shows four nodes Connected with ring topology
Advantages • ease of installation and reconfiguration • fault detection and isolation is easy Disadvantages • unidirectional traffic • break in ring can disable entire network Applications • office building and school campus
Different connecting devices used are • hub • repeater • bridge • switch • router • gateway
