Network Topology

 

Network Topology

It is the layout or structure of the network in relation with the flow of data. It is the way in which the elements such as computers, printers, servers, and other computing appliances are arranged in a network. In this instance, you take note not only of the device's location, but also how it is connected to the network, the type of cables in use, and its layout.

Types of Network Topologies

1.)   Linear Bus Topology

Is a type of network topology in which each devices is connected one after the other in a sequential chain. It uses one long cable, referred as backbone, to which computers and other devices are attached. A terminator is placed at each end of the backbone to keep the signals from bouncing back and being received again by the nodes. In this case, the bus is the network connetion between the devices, and if any link in the network chain is severed, all the network transmission is halted.  

Advantages of Linear Bus Topology

• Easy to connect a computer or peripheral to a linear bus.

• Requires less cable length than a star topology.

 

Disadvantages of Linear Bus Topology

• Entire network shuts down if there is a break in the main cable.

• Terminators are required at both ends of the backbone cable.

• Difficult to identify the problem if the entire network shuts down.
• Not meant to be used as a stand-alone solution.

2.)   Star Topology

is a topology for a Local Area Network (LAN) which uses a central device called hub (a more efficient device called “switch” is also used) in which all nodes are individually connected to a central connection point. Data from a computer passes through the hub or switch before it can reach the other target node. It takes more cable that e.g. a bus, but the benefit is that if a cable fails, only one node will be brought down.

Advantages of Star Topology

•  As compared to Bus topology it gives far much better performance, signals don’t necessarily get transmitted to all the workstations. A sent signal reaches the intended destination after passing through no more than 3-4 devices and 2-3 links. Performance of the network is dependent on the capacity of central hub.
• Easy to connect new nodes or devices. In star topology new nodes can be added easily without affecting rest of the network. Similarly, components can also be removed easily.
• Centralized management. It helps in monitoring the network.
• Failure of one node or link doesn’t affect the rest of network. At the same time its easy to detect the failure and troubleshoot it.

 

Disadvantages of Star Topology

• Too much dependency on central device has its own drawbacks. If it fails whole network goes down.
• The use of hub, a router or a switch as central device increases the overall cost of the network.
• Performance and as well number of nodes which can be added in such topology is depended on capacity of central device.

  

3.)   Ring Topology

Is a network configuration in which device connection create a circular data path wherein nodes are connected to each other forming one contiguous pathway.

In a ring network, packets of data travel from one device to the next until they reach their destination. Most ring topologies allows packets to travel only in one direction, called a unidirectional ring network. Others permit data to move in either direction, called bidirectional.

Advantages of Ring topology

• Reduced chances of data collision as each node release a data packet after receiving the token.
• Token passing makes ring topology perform better than bus topology under heavy traffic
• No need of server to control connectivity among the nodes
• Equal access to the resources

 

Disadvantages of Ring topology 

In Unidirectional Ring, a data packet must pass through all the nodes.

Ex: Let’s say A, B, C, D, and E are a part of the ring network. The data flow is from A towards B and henceforth. In this condition, if E wants to send a packet to D, the packet must traverse the entire network to reach D.

 

Single point of failure, that means if a node goes down entire network goes down.

 

1.)   Mesh Topology

A network setup where each computer and network device is interconnected with one another, allowing for most transmissions to be distributed even if one of the connection go down. It is a topology commonly used for wireless networks. Below is visual example of a simple computer setup on a network using a mesh topology. In mesh configuration nodes are interconnected to each other with each node having the capability to independently process and forward request not for just it’s own use, but even manage and request for other nodes and network.

 

Advantages of a Mesh Topology

• Manages high amounts of traffic, because multiple devices can transmit data simultaneously.
• A failure of one device does not cause a break in the network or transmission of data.
• Adding additional devices does not disrupt data transmission between other devices.

 

Disadvantages of a Mesh Topology

• The cost to implement is higher than other network topologies, making it a less desirable option.
• Building and maintaining the topology is difficult and time consuming.
• The chance of redundant connections is high, which adds to the high costs and potential for reduced efficiency.

1.)   Hybrid Topology

Is a type of network topology that uses two 0r more differing network topologies. These topologies include a mix of bus topology, mesh topology, ring topology, star topology, and a tree topology

Types of Hybrid Network Topologies

 

there are different types of hybrid network topologies depending on the basic requirement of an organization but most commonly used one is “Star-Ring” and “Star-Bus” Topologies that makes up the hybrid

 

1.   Star-Ring Network Topology

In a Star-Ring topology, a set of star topologies relate to a ring topology as the adjoining topology. Joining each star topology to the ring topology is a wired connection

 

2.  Star-Bus Network Topology

A Star-Bus topology is the combination of star network topology and bus network topology, in Star-Bus network a set of star topologies are interconnected by a central bus network. Joining each star topology to the bus topology results the Star-Bus topology

Advantages of Hybrid Topology

• Hybrid network combines the benefits of different types of topologies
• Can be modified as per requirement
• It is extremely flexible.
• It is very reliable.
• It is easily scalable

Disadvantages of Hybrid Topology

• It is expensive
• The design of a hybrid network is complex.
• Hardware changes are required in order to connect topology to another topology.