In Computer Networks, Network Topology is the arrangement of the various elements of a communication network. Network Topology is a topological structure of a network and may be depicted physically or logically. So Network topology refers to how devices in a computer network are connected.
Basic Terminology Related to Network Topology
Node: A node refers to any device or point in the network, such as computers, servers, routers, or switches. These nodes are crucial for transmitting and receiving data within the network.
Link: A link signifies a physical or logical connection between two nodes, allowing data to flow between them. Links can be wired (Ethernet cables) or wireless (Wi-Fi).
Topology: Topology is the arrangement or layout of nodes and links in a network. It determines how devices are interconnected and how data travels within the network.
Types of Network Topology
- Bus Topology
- Star Topology
- Ring Topology
- Mesh Topology
Bus Topology
In bus topology, all stations are attached to the same cable. In the bus network, messages are sent to both directions from a single point. In the bus topology, signals are broadcasted to all stations. Each computer checks the address on the signal (data frame) as it passes along the bus. If the signal’s address matches that of the computer, the computer processes the signal. If the address doesn’t match, the computer takes no action and travels down the bus.
Advantages of Bus Topology
- Bus topologies are relatively easy to install.
- It requires less cable length.
- It is simple and easy to implement and extend.
Disadvantages of Bus Topology
- Maintenance costs may be higher in the long run.
- More expensive cabling.
Star Topology
In a star network, all the nodes (PC, printers and peripherals) are connected to the central server. It has a central connection point, like a hub or switch. A star topology is designed with each node connected directly to a central network.
Advantages of Star Topology
- Easy to install and wire.
- It can accommodate different wiring.
Disadvantages of Star Topology
- Star networks can require more cable length than a linear topology.
- More expensive cabling.
Ring Topology
All the nodes in a ring network are connected in a closed circle of cable. Messages that are transmitted travel around the ring unit they are addressed to, the signal being refreshed by each node. In a ring network, every device has exactly two neighbors for communication purposes.
Advantages of Ring Topology
- Fault tolerance builds into the design.
- Data packets travel at a greater speed.
Disadvantages of Ring Topology
- Expensive Topology
Mesh Topology
In mesh topology, every node has a dedicated point-to-point link in every other node. Such a network is called complete because, for any two devices, there is a special link and non-redundant links cannot be added to the main network. In Mesh Topology, if we have to connect ‘n’ computers then we need n(n-1)/2 cables and each computer must have (n-1) Ethernet cards.
Advantages of Mesh Topology
- Redundant links between devices.
- Easy fault identification and isolation.
- An unusual link does not incapacitate the entire system.
Disadvantages of Mesh Topology
- Each node must have an interface for every other node.
- There is only a limited number of I/O ports in a computer.