Network Topologies

Star Topology

• 
• The most common topology for small networks
• Format:
• - a central devices, usually a switch, is the center of the network through which all devices connect to
• Bennefits:
• - Easily scalable (easy to plug another device into the switch), fairly fault taulerant
• Negatives:
• - if central switch fails, all devices fail

Mesh Topology

• Most often used in WANs than in LANs
• Format:
• - every device has one connection to all other devices
• - common for every office in the WAN to be interconnected via dedicated lines
• Positives:
• - redundancy
• Formula for necessary number of connections:
• - n * (n-1)/2 (n = number of devices)
• 

Ring Topology

• Not seen often in LANs - AKA Token Ring
• - popular 20 years ago
• - only rings still used are in Fiber Distributed Data Interface
• - data transmissions are token-based (only one token of data is passed at a time from device to device)
• Positive:
• - helps networks avoid collision
• Negatives:
• -if there is a break in the ring, the network is down
• 

Bus Topology

• 
• Format:
• - every device is connected to a backbone cable that runs from one end of the network to another
• - the backbone cable needs termination at each end
• - without the terminator signals, data cannot bounce back and forth from each end
• - bus networks are best kept in small sizes
• - any break means the enitre network is down