Network topologies and TCP/IP protocolBus topologyThere is nothing simpler than the physical bus topology when it comes to connecting nodes on a local area network (LAN ). The most common implementation of a linear bus topology is IEEE 802.3 Ethernet. All devices in a bus topology are connected to a single cable called a bus, backbone, or ether. The medium of transmission has a physical beginning and end. All connections must be terminated with a resistor to prevent data transmissions from being mistaken for network traffic. The termination resistor must match the cable impedance. An advantage of bus topology is that small networks are fairly easy to set up and do not require specialized networking equipment. It's also quite economical to set up, requiring the least amount of cables and equipment. Adding or removing nodes is fairly simple, but moving nodes without affecting neighboring nodes can be difficult. Troubleshooting media on a bus network can be very tedious, as a break in the backbone will knock out the entire LAN. For this reason, the bus topology is not considered one of the most robust network topologies, compared to the star or mesh topology. A loose or missing termination resistor can also bring down a LAN. Star topology In this topology, all nodes are connected to a central device, usually a hub or switch. Each connected device has a dedicated point-to-point connection between the device and the hub. The star network topology is by far the most widely implemented topology in use today. Star topology networks require more cabling than bus, but the trade-off comes in the form of a more robust network topology. A network media outage will only affect a single node, as each node has a dedicated connection to the central device; a hub or switch. This also makes the central device a Single Point of Failure (SPOF). Redundant or failover switches are often used to eliminate SPOF in a star LAN. Building a star topology is much more expensive and time-consuming than a bus network. The biggest costs come in the form of cabling and central devices. However, star topologies can be easily expanded to accommodate more nodes, and troubleshooting is much easier because connectivity problems are easier to isolate than in a bus network. Mesh TopologyPerhaps the most redundant and fault-tolerant of all network topologies is the mesh LAN. Every node is connected to every other node for a true point-to-point connection between every device on the network.