Mesh Topology

Every device has a dedicated point-to-point link to every other device.

• Links for $n$ nodes: $n(n-1)/2$; each node needs $n-1$ ports.

Advantages

• No traffic problems; dedicated links
• Robust: failure of one link does not affect others
• Privacy and security (point-to-point)
• Easy fault identification

Disadvantages

• Very high cabling and port cost
• Complex installation and reconfiguration
• Poor scalability

Star Topology

All devices connect to a central hub/switch; no direct links between devices.

• Links for $n$ nodes: $n$; each node needs one port.

Advantages

• Cheap, easy to install and extend
• Failure of one node/link does not affect others
• Easy fault detection and management

Disadvantages

• Central hub is a single point of failure
• Needs more cable than bus; hub capacity limits network size

Comparison

Basis	Mesh	Star
Links (n nodes)	n(n-1)/2	n
Cost	Very high	Low
Reliability	Very high	Depends on central device
Scalability	Poor	Good
Ports per device	n-1	1
Use	Backbone/critical networks	LANs (Ethernet with switch)