“The layout pattern & connectivity scheme between the devices in a network is called network topology”. It is a virtual shape or structure of the network. Devices on the network are called as nodes. The most common nodes are computers and peripheral devices. Network topology is a virtual illustration of these nodes and their connections using physical cabling. There are a number of different types of network topologies which are broadly divided into two types:
- Physical Network Topology: Actual Connectivity/Layout as per real cabling & connections
- Logical Network Topology: Virtual view of the network that member devices see
Physical Network Topology Types
There are many types of Physical Network Topology, out of which, most common 7xtypes include Point-to-Point, Ring, Mesh, Star (Hub/Spoke), Bus, Tree and Hybrid.
Let’s discuss each type one by one.
1. Point-to-Point Network Topology
Point-to-point topology is the simplest of all network topologies. The network simply consists of a direct link between two computers for a faster and more reliable connection. Using circuit-switching or packet-switching technologies, a point-to-point circuit can be set up dynamically and dropped when no longer needed. Switched point-to-point topologies are the basic model of conventional telephony.
This is fastest network topology because there is a direct connection so no broadcast is required on such network types. p-p topology is the most reliable than all other types of the connections because there is a direct connection. But p-p topology can only be used for small areas where computers are in close proximity & short distance. Below figure shows a Point-to-Point Network Topology along with its Advantages & Disadvantages:
2. Ring Network Topology
In Ring topology, the devices in the network are connected in a circle. Each device has two paths to send & receive data. If one link goes down, data could be sent from the other side. A ring topology is similar to a bus topology in a closed loop. In this type of topology, data travels around the ring in one direction. When one node sends data to another, the data passes through each intermediate node on the ring until it reaches its sink or destination. The intermediate nodes simply repeat the data to keep the signal strong.
Ring Network Topology is more secure because if one link is broken in the Ring, data can travel from the side. It is easy to Troubleshoot and easy to Install. However, in Ring Network Topology, Scalability and expansion in existing network is a bit difficult & requires more skill. Below figure shows a Ring Network Topology along with its Advantages & Disadvantages:
3. Mesh Network Topology
In Mesh network topology, every device is interconnected to every other device in the network. Nodes are connected to each other in a redundant fashion with multiple connections. There are two types of mesh topologies, Partial Mesh and Full Mesh. Mesh Network Topology is the most stable & fault tolerant. It is cable fault & device fault tolerant. However, it is the most expensive as it requires more cabling & infrastructure. Below figure shows a Mesh Network Topology along with its Advantages & Disadvantages:
4. Star Network Topology
In a Star Topology every device is connected to a central device such as a switch. Star topology requires more cable as compared to other topologies but it mode robust as a failure in one cable will only disconnect the specific connected computer via that cable to the central device. Star Network Topology is easier to manage. It is easier to locate node and cable problems in it and it is well suited for expansion into high-speed networking. However, it contains single point of failure and requires more network cable.
Below figure shows a Star Network Topology along with its Advantages & Disadvantages:
5. Bus Network Topology
It is an old topology. In this type of topology, one main trunk is chosen a backbone & all devices connect to it using T connectors or taps. It is cheap as it requires less cabling. Bus Network Topology doesn’t need any special equipment and it is less complex. However, Network down time is required whenever devices are added/removed. It is more prone to problems. If once cable goes down then whole network is disturbed. A signal from the source travels in both directions to all machines connected on the bus cable until it finds the intended recipient. If the machine address does not match the intended address for the data, the machine ignores the data. Alternatively, if the data matches the machine address, the data is accepted. Below figure shows a Bus Network Topology along with its Advantages & Disadvantages:
6. Tree Network Topology
It is a topology in which network devices are connected in a tree manner. A tree network is also called star-bus network. Tree network topology is basically a combination of Star & Bus. It is a hybrid network topology in which star networks are interconnected via bus networks. Tree networks are hierarchical in nature and each node can have multiple no. of child nodes.
Tree Network Topology is a loop free topology & is used mostly in Layer2 Networks. It is an easy to scale network. We can simply continue adding devices on branches with no down time required. However, there is a Single Point of Failure in case the Backbone goes down. Below figure shows a Tree Network Topology along with its Advantages & Disadvantages:
7. Hybrid Network Topology
Hybrid network is simply a combination of more than one network topology types. e.g. Ring & bus combine together. With Hybrid Network Topology, we can achieve combined advantage of individual member topologies if properly designed. However, it becomes complex if the network is no properly designed. Below figure shows a Hybrid Network Topology along with its Advantages & Disadvantages: