What is network topology and what are its different types?7 min read

Network topology

A node is a machine or system that is part of a network. The Network Topology is the geometrical arrangement of computer resources, remote devices, and communication facilities. If you want to learn about different types of computer networks, click here.

1. BUS NETWORK

Each computer in a Bus Network is connected to a single communication cable with a termination at each end via an interface, allowing each computer to communicate directly with another computer or device on the network. This topology is often used in combination with a LAN. This topology is common in client-server networks, in which one of the network’s machines is configured as a server that distributes data files. The BUS topology is the simplest and most widely used network design.

Bus network topology
Bus network topology
Advantages:
  1. Short cable length and simple wiring layout.
  2. Resilient architecture.
  3. Easy to extend.
Disadvantages:
  1. Fault diagnoses are difficult.
  2. Fault isolation is difficult.
  3. Repeater configuration.

2. RING NETWORK

This network topology is similar to linear BUS, also known as circular network topology. A Ring Network is made up of many devices or computers that are linked in a closed loop by a single communication cable. Each node transfers data from one to the next before it reaches its final destination. Since each section of the cabling system only handles data flow between two devices, performance is faster on this system. Peer-to-peer networks use this topology, in which each computer is responsible for both information transmission and data file delivery. A loop network is another name for a ring network. A ring can be unidirectional or bidirectional.

Ring network topology
Ring network topology
Advantages:
  1. Short cable length.
  2. No wiring closet space required.
  3. Suitable for optical fibers.
Disadvantages:
  1. Node failure causes network failure.
  2. It is difficult to troubleshoot a ring network.
  3. Adding or removing computers disrupts the network.

3. STAR NETWORK

Each computer on a Star Network is connected to a single, centrally located file server, using its own dedicated segment of cable. Star network communicates with a central hub that resends messages either to the entire computers or only to the destination computer Hub is a device used to extend a network so that additional workstations can be attached. The hub in the broadcast star network can be active or passive. This topology has the advantage of minimum data traffic along with the cables (nodes to the server only), thus providing optimum performance. But because a single machine must coordinate all the data communications, this topology requires an extremely powerful and expensive file server.

Star network topology
Star network topology
Advantages:
  1. Ability to centralize file information, software, and equipment at the host computer.
  2. It is possible to link terminals and microcomputers to the same host.
  3. Ability to use new software products, that enable dedicated micro-computers to act as hosts.
  4. Any breaks in the cable affect only one computer in the circuit; other links would be active.
  5. Robustness
  6. Early fault identification / fault isolation.
  7. Monitors link problems and bypass defective links.
  8. Less cable used than a mesh network.
Disadvantages:
  1. It is costly to set up since this form of network consumes the most cable (network cable is expensive)
  2. It is necessary to purchase additional hardware (hubs or switches), which increases the cost. All devices connected to a hub or switch will lose their network link if it fails.
  3. Hacking is a possibility, particularly with wide-area networks. Security protocols, such as a firewall, are necessary to avoid such abuse.

4. TREE NETWORK

This is a network topology with several nodes linked in a hierarchical fashion. The root is the node at the very top of the tree. It may have zero or more child nodes, which are all connected by edges (linked). The root is the parent node of its children. A sibling is a child node that has zero or more children of its own nodes that all share the same parent. Every node in a tree has exactly one parent node and all nodes in the tree are descendants of the root node. These relationships ensure that there is always one and only one path from one node to any other node in the tree.

Tree network topology
Tree network topology
Advantages:
  1. Leaf nodes can accommodate more nodes in the hierarchical chain, making it scalable.
  2. Each intermediate node of a tree topology represents a node in the bus topology by point-to-point wiring to the central hub.
  3. The others are unaffected if one of the hierarchical networks is weakened.
  4. Maintenance and fault detection is simplified.
Disadvantages:
  1. There will be a lot of cabling.
  2. It requires a lot of maintenance.
  3. The backbone creates the point of failure.

5. MESH NETWORK

A Mesh Network topology has a point-to-point connection between every device in every network. In this network, zero or more nodes are linked together in an arbitrary fashion. Any two nodes in a graph may be connected by a link. Not all the nodes in a graph need to be connected, but if a path can be traced between any two nodes the graph is a connected one. You use mesh topology in a hybrid network with just the largest or most important sites interconnected.

Mesh network topology
Advantages:
  1. It has dedicated links guaranteeing each connection to carry its data load.
  2. Eliminates traffic problems.
  3. Point to point link makes it easier to identify the Faults.
  4. Whenever a problem occurs, traffic could be diverted to another link.
  5. The network manager could identify the precise location of the fault and cause to give a solution, f. Privacy and security are available.
Disadvantages:
  1. Cabling cost.
  2. Number of I/O ports required.
  3. Installation and re-configuration difficulty
  4. The amount of wiring can be greater than the space available through walls, ceilings and floors etc.

6. Hybrid Network

Hybrid networks are networks that utilize multiple topologies. WANs often use point-to-point links to connect remote rings or stars. Some examples of the hybrid topology are the Star Bus, Star Ring.

Hybrid network topology

Star Bus:
The Star Bus topology is a combination of the bus and star topologies in which several star topology networks are linked together by linear bus trunks. If the computer develops a fault, it does affect the network. If the hub fails, all the computers on that hub are disabled.

Star Ring:
The Star Ring topology is a combination of the star and the ring topologies. In a star pattern, the various ring topologies are bound to the hub. As LANs and MANs are connected to form enterprise and global networks, hybrid topologies are becoming more common.


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