A local area network (LAN) is a computer network in a small area like a home, office, or school. Many computers can be connected to share information and Internet connections. Most LANs use Ethernet to connect together.
LAN topologies tell you how network devices are organized. Five common LAN topologies exist: bus, ring, star, tree, and mesh. These topologies are logical architectures. This means that they tell you the directions that signals go between devices, but that the actual cables that connect the devices might not be connected the same way. For example, logical bus and ring topologies are commonly organized physically as a star.
A bus topology means that the signal is put onto the medium and every device on the bus receives the signal. If more than one device tries to send a signal at the same time, they can interfere with each other. A long copper wire with other wires tapped into it is an example of a bus topology.

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