Network topologies describe the ways in which the elements of a network are connected. They describe the physical and logical arrangement of network nodes. Let us look at the advantages different network topologies offer, and their shortfalls.
- It is best-suited for small networks.
- It is easy to set up, handle, and implement.
- It costs very less.
- It is not easy to isolate faults in the network nodes.
- It is suitable for networks with low traffic. High traffic increases load on the bus, and the network efficiency drops.
- The cable length is limited. This limits the number of network nodes that can be connected.
- This network topology can perform well only for a limited number of nodes. When the number of devices connected to the bus increases, the efficiency decreases.
- It is heavily dependent on the central bus. A fault in the bus leads to network failure.
- Each device on the network "sees" all the data being transmitted, thus posing a security risk.
- In this topology, each node has the opportunity to transmit data. Thus, it is a very organized network topology.
- The adding or removing of network nodes is easy, as the process requires changing only two connections.
- The traffic is unidirectional and the data transmission is high-speed.
- The data being transmitted between two nodes passes through all the intermediate nodes. A central server is not required for the management of this topology.
- In comparison to a bus, a ring is better at handling load.
- The configuration makes it easy to identify faults in network nodes.
- It is less costly than a star topology.
- Data sent from one node to another has to pass through all the intermediate nodes. This makes the transmission slower in comparison to that in a star topology. The transmission speed drops with an increase in the number of nodes.
- The failure of a single node in the network can cause the entire network to fail.
- The movement or changes made to network nodes affect the entire network's performance.
- There is heavy dependency on the wire connecting the network nodes in the ring.
- It can handle heavy traffic, as there are dedicated paths between any two network nodes.
- The arrangement of the network nodes is such that it is possible to transmit data from one node to many other nodes at the same time.
- The failure of a single node does not cause the entire network to fail as there are alternate paths for data transmission.
- Point-to-point contact between every pair of nodes, makes it easy to identify faults.
- A lot of cabling is required. Thus, the costs incurred in setup and maintenance are high.
- The arrangement wherein every network node is connected to every other node of the network, many connections serve no major purpose. This leads to redundancy of many network connections.
- Owing to its complexity, the administration of a mesh network is difficult.
- As the analysis of traffic is easy, the topology poses lesser security risk.
- Adding or removing network nodes is easy, and can be done without affecting the entire network.
- Due to its centralized nature, the topology offers simplicity of operation.
- It also achieves isolation of each device in the network.
- Due to the centralized nature, it is easy to detect faults in the network devices.
- Data packets do not have to pass through many nodes, like in the case of a ring network. Thus, with the use of a high-capacity central hub, traffic load can be handled at fairly decent speeds.
- Also, the number of nodes that can be added, depends on the capacity of the central hub.
- Network operation depends on the functioning of the central hub. Hence, central hub failure leads to failure of the entire network.
- The setup cost is quite high.
Imagine a hierarchy of network nodes, with the root node serving client nodes, that in turn serve other lower-level nodes. The top-level node is mostly a mainframe computer while other nodes in the hierarchy are mini or microcomputers. In this arrangement, the node at each level could be forming a star network with the nodes it serves. In this case, the structure combines star and bus topologies and inherits their advantages and disadvantages.
- Fault identification is easy.
- The advantages of centralization that are achieved in a star topology are inherited by the individual star segments in a tree network.
- The tree topology is useful in cases where a star or bus cannot be implemented individually. It is most-suited in networking multiple departments of a university or corporation, where each unit (star segment) functions separately, and is also connected with the main node (root node).
- Each star segment gets a dedicated link from the central bus. Thus, failing of one segment does not affect the rest of the network.
- The network can be expanded by the addition of secondary nodes. Thus, scalability is achieved.
- Owing to its size and complexity, maintenance is not easy and costs are high. Also, configuration is difficult in comparison to that in other topologies.
- As multiple segments are connected to a central bus, the network depends heavily on the bus. Its failure affects the entire network.
- Though it is scalable, the number of nodes that can be added depends on the capacity of the central bus and on the cable type.
A hybrid topology combines two or more topologies and is meant to reap their advantages. Obviously, the advantages and disadvantages of a hybrid topology are a combination of the merits and demerits of the topologies used to structure it.