HYBRID TOPOLOGY AND ITS ADVANTAGES AND DISADVANTAGES
It is typical for networks to implement a mixture of topologies to form a hybrid topology. For example, a very popular hybrid topology is a star-bus topology, in which a number of star topologies are connected by a central bus. This is a popular topology because the bus will connect hubs that are spread over a distance. Another very popular hybrid topology is the star-ring topology. The star-ring topology is popular because it looks like a star but acts as a ring. For example, there is a network architecture known as Token Ring (more on this later, in the section “Network Architectures”) that uses a central “hub” type device, but the internal wiring makes a ring. Physically it looks like a star, but logically it acts as a ring topology.
|Figure: Hybrid Topology.|
Advantages of Hybrid Network Topology
1) Reliable: Unlike other networks, fault detection and troubleshooting are easy in this type of topology. The part in which fault is detected can be isolated from the rest of the network and required corrective measures can be taken, WITHOUT affecting the functioning of the rest of the network.
2) Scalable: It’s easy to increase the size of the network by adding new components, without disturbing existing architecture.
3) Flexible: Hybrid Network can be designed according to the requirements of the organization and by optimizing the available resources. Special care can be given to nodes where traffic is high as well as where chances of fault are high.
4) Effective: Hybrid topology is the combination of two or more topologies, so we can design it in such a way that the strengths of constituent topologies are maximized while their weaknesses are neutralized. For example, we saw Ring Topology has good data reliability (achieved by the use of tokens) and Star topology has high tolerance capability (as each node is not directly connected to the other but through a central device), so these two can be used effectively in hybrid star-ring topology.
Disadvantages of Hybrid Topology
1) Complexity of Design: One of the biggest drawbacks of hybrid topology is its design. It’s not easy to design this type of architecture and it’s a tough job for designers. The configuration and installation process needs to be very efficient.
2) Costly Hub: The hubs used to connect two distinct networks, are very expensive. These hubs are different from usual hubs as they need to be intelligent enough to work with different architectures and should be functional even if a part of the network is down.
3) Costly Infrastructure: As hybrid architectures are usually larger in scale, they require a lot of cables, cooling systems, sophisticated network devices, etc.