The schematic description of a network is called a topology. It refers to the layout of the different devices in a network. The arrangement of the network components can be either physical or logical. There are many network topologies: bus, mesh, star, ring, tree, and hybrid.
- Bus topology
A bus topology represents a layout where all the networking components are connected using a central connection, which is sometimes referred to as a backbone. This type of topology is very cost effective because it uses a single expendable cable. It is a good choice for small networks, but when the cable goes down, all the connected devices goes down. As a network architect, it is better to avoid the single point of failure approach.
- Star topology
A star topology refers to connecting all the devices to a single hub, which is a central node with a dedicated connection to every device. The role of the hub is to repeat the data flow. It is easy to manage and to troubleshoot, but it is a little bit expensive compared to other topologies.
- Ring topology
A ring topology represents a ring layout where the data transmission is done in one direction. It represents a single point of failure, like the bus topology.
- Tree topology
A tree topology is a hierarchical layout. You can see it as a combination of the bus topology and the star topology. Sometimes, it is considered as another form of the star topology. It contains a root node and other devices and is a good choice for a grouped workspace, but it is heavily cabled.
- Mesh topology
In a mesh topology, every connected device is connected to every other device in the network, using a point-to-point connection. This type of topology is expensive, but it is recommended in a redundancy architecture because if a device fails, the data goes to another machine, generally using the shortest path.
- Hybrid topology
A hybrid topology is a combination of at least two topologies of the layouts discussed previously. Based on your requirements, you can choose some topologies to fulfill the needs of your different departments. It is effective and flexible.
After studying the different topologies of a network, now let’s look at how the data is transmitted between two different devices. When it comes to communications, we have three main transmission categories:
- Simple mode: This mode occurs when the data is flowing in only one direction. This type is widely used in television broadcasting (you can only send data from a source to monitor and not the opposite).
- Half-duplex mode: In this type of transmission, the data goes in both directions using a single means of communication at a time, such as ping-pong mode; you can’t send and receive a message at the same time.
- Full-duplex mode: This mode is used when the data flow is bi-directional and simultaneous, like the mode used in telephone networks.