1. Physical Topologies -K. M. THANVI
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

2. Types There are four basic types of network topologies Mesh topology
Star topology
Bus topology
Ring topology

3. 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

4. Figure shows 6 nodes connected with mesh topology

5. Advantages Disadvantages Applications Robust Privacy and security
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

6. 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.

7. Figure shows 5 nodes connected with mesh topology

8. Advantages Disadvantages Applications
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

9. 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

10. Figure shows different nodes
Connected with bus topology

11. Advantages Disadvantages Applications 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

12. 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

13. Figure shows four nodes
Connected with ring topology

14. Advantages Disadvantages Applications
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

15. Connecting devices

16. Different connecting devices
used are
hub
repeater
bridge
switch
router
gateway

17. HUB

18. REPEATERS

19. BRIDGE

20. SWITCH

21. ROUTER

22. GATEWAY