Computer Topology and Their Work

Computer Topology and Their Work-: The term ‘topology’ refers to the way a network is laid out , either physically or logically. Topology can be referred as the geometric arrangement of a computer system each computer system. In a topology is known as node network to close determine only by the configuration of connection between nodes.

In other words, Topology is the method in which network are physically connected together. Topology determines the complexity of connecting computer and their fore the cost of network cable installation Cable installation can often be a major cost factor for network system.Topology also determine the strategy for physically expanding the network in future .

Different Topologies are described in the following sub – section .

• Bus Topology 
• Star Topology 
• Ring or circular Topology 
• Mesh Topology
• Tree Topology 

Bus Topology 

In linear bus topology, all computers are connected by a single length of cable with a terminator at each end. The bus topology is the simplest and most widely used Local Area Network. Design it is a passive topology which means only one computer at a time can send a message. Hence, the number of computers attached to a bus network can significantly affect the speed of network. A computer must wait until the bus is free before it can transmit. Each node is connected to two others expect the machines at either end of the cable,which are connected only to one other node.

The network operating system keeps track of a unique electronic address for each node, and manages the flow of data based on this addressing scheme. This topology has the advantage of not requiring that every computer be up and running in order for the network to function . But because a single cable is dedicated to all the information trafic , performance can be slow at times. This topology is often found in client/server system, where one of the machines on the network is designated as a file server meaning that it is dedicated solely to the distribution of data files, and is not typically used for information processing.

Features of Bus Topology

• It Transmits data only in one direction.
• Every device is connected to a single cable.
• It is a cable dad both ends are closed where along the cable there are nodes.
• Most prevalent because it is simple installation.
• The biggest problem if one cable broke or lose than the whole network will die.
• The single passes to direction with 1 cable that may occur collision or data collision.
• Using a coaxial cable.
• Using the BNC connector.
• The bus topology is the transmission line where the signal is received and sent on each device connected to one straight line cable the signal will only be captured by the intended device while other tools ignore the signal.

Advantages of Bus Topology

• All the nodes are connected directly, so very short cable length is required.
• The architecture is very simple and linear.
• Bus topology can be extended easily on either sides.
• The best topology is simple real able easy to use and understand in small size to Local area network.
• The bus required the least amount of cable to connect the computer together and is there for less expensive than other cabling arrangement.
• It is easy to extend a bus to cables can be joint into one longer cable with a connector making a longer cable and allowing more computers to join the network.

Disadvantages of Bus Topology

• In case of any fault in data transmission fault isolation is very difficult we have to check the Internet work to find the fault.
• Becomes slow with increase in number of nodes .
• The entire network shutdown if there is an error occurs in the main cable.
• It is difficult to trouble shoot a bus a cable break or malfunctioning computer anywhere between two computers can cause them not to be able to communicate with each other cable break or loose connector will also cause reflection and bring down the whole network causing all network activity to stop.
• Heavy network traffic and slow down a bus considerably because any computer can transmit at any time and computer or most bus network do not co-ordinate with each other two reserve time is slow to transmit a bus network with many computers can send a lot of its bandwidth capacity for transmitting information with the computer interpreting each other instead of communicating the problem only get worse as more computer are added to the network.

Example of bus topology

• Ethernet 
• Local Talk 
• CSMA/CD 

Star Topology

Each computer on a Star Network communicates with a central hub that a re- sends the message either to all the computers (in the broadcast star network) or only to the destination computer (in a switched star network). The hub in a broadcast Star Network can be active or passive.

An active hub regenerate the electrical signal and send it to all the computers connected to it this type of hub is often called up Multiport repeater. Active hubs and switches require electrical power to run a passive her medley act as a connector point and does not amplifier aur regenerate the signals passive hubs do not require electrical power to run.

You can use several types of cable to implement a Star Network. Hybrid hub can accommodate several types of cable in the same Star Network. You can expand a Star Network by placing another star hub where a computer might otherwise go, allowing several more computers or hubs to be connected to that hub. This create a hybrid Star Network.

Features of Star Topology

• Every nude has its own dedicated connection to the hub.
• Hub acts as a repeater for data flow.
• Can be used with twisted pair , Optical fibre or coaxial cable.

Advantages of Star Topology

•  Installation of star topology is very easy as all notes are directly connected to the central node or server.
• Easy to detect fault and remove it.
• Failure of single system will not bring down the network.
• It is much easier to modify or add new computer to us Star network without disturbing the rest of the network you simply run a new line from the computer to the central location and plug it into the hub when the capacity of the central herb is accident you can replace it with one that has a larger number of force to plug lines into it .
• The centre of a Star network is a good place to diagnose network fault intelligent her hub with microprocessor that implement feature in addition to repeating network signal also provide for centralized monitoring and management of the network.
• Single computer failure not necessity bring down the whole Star Network the hub can detect a network fault and isolate the of pending computer or network cable and allow the rest of the network to continuous operation.
• You can use several cable types in the same network with a hub that can accommodate multiple cable types.

Disadvantages of Star Topology

• Require more cable less than bus topology.
• Is hub aur server fails then tired network will be disabled.
• Difficult to expand as the new node has to connect all the way to central node.
• If central hub fails the whole network fail to operate.
• Many Star Network required a device to the central point to rebroadcast or switch the network traffic.
• It cost more to cable a Star Network because all network cable must be pull to one centre point requiring more cable length then other networking technology topologies.

Example of Star Network

• ATM (Asynchronous Transmission Mode )

Ring or circular Topology

This layout is similar to the linear bus, except that the nodes are connected in a circle using cable segment. In this layout ,each node is physically connected to only two other nodes. Each node passes information along to the next, until it arrives at its intended destinations.Since each computer re- transmits what it receives, a ring is an active network and is not subject to the signal loss problem which a bus technology experiences. There is no termination because there is no end to the ring performance on this type of topology is faster because each portion of the cabin system is handling only the date of flow between two machine this type of technology can be found in peer to peer networking with each machine manage both information processing and the distribution of data file.

Features of Ring Topology

• Data is transferred in a sequential manner that is bit by bit data transmitted has to past through each node of the network till the destination node.
• In dual ring topology to ring network are formed and data flow is in opposite direction in them also if one drink fail the second drink can acts as a breakup to keep the network up.
• The transmission is unidirectional but it can be made by directional by having two connection between each network node it is called dual ring topology.
• A number of repeaters are used for ring topology with large number of node because if someone wants to send some data to the last node in the ring topology with hundred note then the data will have to pass through 99 note to reach the 100th node has to prevent data lose repeater are used in the network.

Advantages of Ring Or Circular Topology

• short cable length is required.
• Suitable for optical fibre as the data flow in one direction.
• It is less costly than star topology.
• Because every network is given equal access to the token no one computer can monopolize the network.
• The fair sharing of the network allowed the network to the great gracefully it continue to function in a shower manner rather than fail .

Disadvantages of Ring or Circular Topology

• fault diagnosis is very difficult in a network formed using ring topology.
• Failure of single network affect the whole network.
• Adding or removing the computer disturbs whole network activity.

Example of Ring Topology

• IBM Token Ring 
• FDDI ( Fiber distributed Data Interface.

Mesh Topology 

It is also known as completely interconnected topology. In mesh topology, every node has a dedicated Point-to-Point link to every other node. It provides a bi-directional link between each possible node. This type of network topology contain at least two node with two or more path between the mist topology is robust because the failure of any one computer does not bring down the entire network.

Features of Mesh Topology

• Not flexible.
• Fully connected.
• Robust.

Advantages of Mesh Topology 

•  Excellent for long distance networking.
• Communication possible through the alternate route if one path is busy.
• It’s performance is not affected with heavy load of data transmission.

Disadvantages of Mesh Topology

• Long wire /cable length, hence increase in the cost of installation and maintenance.
• The hardware required to connect each link is expensive.

Example of Mesh Topology

• Bluetooth.
• System of WiFi.
• Network used in military agency.
• Home Automation.

Tree Topology

This is a network in which notes are arranged as a tree. The function of the Central nodes in this topology mein bhi distributed. Its basic structure is like and inverted tree, where the route act as a server. The three topology stimulates hierarchical flow of data. It allow more devices to be attached was single hub.­

Features of Tree Topology

• Ideal if workstation are located in groups.
• Used in Wide Area Network.

Advantages of Tree Topology

• The treat topologies stimulates hierarchical flow of data so it is suitable for application where he radical flow of data and control days required.
• We can easily extend the network.
• If one segment is damage other segment you are not affected.

Disadvantages of Tree Topology

• Long cable or required.
• There are dependencies on the root node.
• If the central hub share the entire system breaks down.

Example of Tree Topology

• Used in data base .
• Coperate Network .