What is Topology ?

• Talks about device arrangement

1. Mesh Topology

• All devices are interconnected (each node is connected to every other node)
• For eg: 4 devices are interconnected then the number of cables are 6 \(Cables = n*(n-1) / 2\) $$Ports = n*(n

• 1)$$

• Highest reliability compared to other topology

• Cost increases when multiple devices are connected due to the increase in number of cables

• Provides security (eg: we may not know how ‘A’ communicates with ‘D’)

• Maintenance is high

• Supports point-to-point communication (also known as dedicated communication, like ‘LAN’)

2. Hub Topology

• Also called ‘Star Topology’
• Hub is a multiport device (multiple devices are connected through hub)
• Number of cables = Number of Ports = n
• No reliability (if there is a problem in hub then there is no communication)
• Cost is normal or genuine (compared to mesh it is low)
• Security is low (since it broadcasts the message)

• Also a point-to-point communication (direct communication)

3. Bus Topology

• Number of Cables = n + 1
• The horizontal line is called as ‘Backbone Cable’
• Number of Ports = n
• No reliability (since there is a single point of failure)
• No security (since the cable cannot decide / filter the information, only a switch or router can)
• Cost
• cheap
• Terminator or Repeater in the ends of the cable(it increase the signal strength so it can cover more distances)
• This is a multi-point (here collision rate is also high = ‘n’)

4. Ring Topology

• In simple words its the end-to-end connection of the bus topology
• Number of Cables = n + 1
• Number of Ports = n
• Less reliable (single point of failure)
• No security
• Cost
• cheap
• It is uni-directional (we use token ring to reduce collision)

NOTE :

• ‘n’ means Node