Ravi Namboori Case Study - Network topologies

Ravi Namboori, a Cisco evangelist and an IT entrepreneur, is based out of Bay Area, California. Ravi Namboori holds nine Cisco certifications, in addition to one each from Microsoft and Novell in networking. Ravi Namboori earned his MBA from The F.W. Olin Graduate School of Business at Babson College.

Think of a topology as a network's virtual shape or structure. This shape does not necessarily correspond to the actual physical layout of the devices on the network. For example, the computers on a home LAN may be arranged in a circle in a family room, but it would be highly unlikely to find a ring topology there.
Network topologies are categorized into the following basic types:

bus
ring
star
tree
mesh
More complex networks can be built as hybrids of two or more of the above basic topologies.
Bus Topology

Bus networks (not to be confused with the system bus of a computer) use a common backbone to connect all devices. A single cable, the backbone functions as a shared communication medium that devices attach or tap into with an interface connector. A device wanting to communicate with another device on the network sends a broadcast message onto the wire that all other devices see, but only the intended recipient actually accepts and processes the message.
Ethernet bus topologies are relatively easy to install and don't require much cabling compared to the alternatives. 10Base-2 ("ThinNet") and 10Base-5 ("ThickNet") both were popular Ethernet cabling options many years ago for bus topologies. However, bus networks work best with a limited number of devices. If more than a few dozen computers are added to a network bus, performance problems will likely result. In addition, if the backbone cable fails, the entire network effectively becomes unusable.