Ring/Mesh/Star & Bus topology

Hello,

The following is my understanding for your reference.

Topology	Advantages	Disadvantages	Application scenarios
Ring	Redundancy is available. If a link in one direction fails, the link in the other direction can be used for communication.	1. Poor scalability 2. Relatively complex management and maintenance	1. Between the access layer and aggregation layer 2. Between the aggregation layer and core layer
Star	1. The structure is simple and easy to manage and maintain. 2. Simple control and easy network construction. 3. Facilitate fault detection and isolation. 4. The communication between terminals is efficient.	Poor redundancy and prone to single point of failure.	1. Used at the access layer to connect to terminals. 2. Used to connect the lower-level network to the upper-level network.
Mesh	1. High network redundancy. 2. Flexible route selection. 3. The access efficiency is high when network segments communicate with each other.	1. High networking costs. 2. Low scalability.	1. Between the aggregation layer and access layer. 2. Between the core layer and aggregation layer.
Bus	1. Simple network structure 2. Easy expansion	1. The link access efficiency is low. Only one terminal can send data in a time segment. Otherwise, a conflict occurs. 2. A link fault affects a wide range of services.	1. All terminals are connected to coaxial cables. 2. Network constructed by hubs

Ring topology

Star topology

Mesh topology

Bus topology

In a ring, each device has two paths to any other device, which is good for redundancy. However, all traffic passes through the ring link, which requires high bandwidth on interfaces. In addition, when the network is changed or faulty, service packets may be lost for a short time due to path switching.
To provide redundancy in a star topology, two links are required for each device. Because the bandwidth requirements of each device are independent, so the bandwidth requirements of each interface are lower than those of the ring network. However, even if links are redundant, if a core device is faulty, all services will be interrupted. Therefore, two core devices need to be deployed in active/standby mode or stack mode for redundancy.
In conclusion, the two topologies have their own advantages and disadvantages. In practice, if the cost permits, you can consider using the two topologies together.