In a ring network, each device (eg workstation, server, printer) is connected in a ring so each one is connected to two other devices. Each date packet on the network travels in one direction. Each device receives each packet in turn until the destination device receives it. The advantages of the ring network is easy to install cheap to install - it does not require much cabling. The disadvantages are if the main cable fails or gets damaged, the whole network will fail as more workstations are connected, the performance of the network will fail and become slower because of data collisions. Also every workstation on the network 'sees' all of the data on the network, which can be a security risk.
In a star network, each device on the network has its own cable that connects to a switch or hub . This is the most popular way of setting up a LAN. You may find a star network in a small network of five or six computers where speed is a priority. The advantages are that kkithis type of network can transfer data quickly (even if there are a large number of devices connected) as data only flows in one direction so there won't be any data collisions. The disadvantages are if the main cable fails or any device is faulty, then the whole network will fail - a serious problem in a company where communication is vital.