Corkomputer Netw

Computer NetworkRAJAT

Definition

A network is a group of interconnected computers. They share resources such as electronic mail, bulletin boards, and access to unique database. They can be thought of as information highways for data.

Data Communication System ELEMENTSTransmitterTransmission MediumReceiversHardwareCommunication NetworkCommunication software Data Communication provider Communication protocol

Network TopologyThe term topology in the context of communications network refers to the way in which the end points or the stations of the networks are linked together. It determines the path that may be used between any pair of station of the network.

Types of Topologies

Bus TopologyStar Topology Ring TopologyMesh TopologyTree Topology

Bus Topology. In bus topology network, a single coaxial cable acts as a backbone to link all the devices in the networks. This topology uses the least amount of cabling and is therefore the least expensive and the simplest topology for small networks. In this network, a 50 ohms terminator terminates both ends of the networkA bus topology consists of a single central cable to which all computers and other devices connect. A bus topology is also known as a bus network.

Bus Topology Advantages Disadvantages Help to reducing the number of physical line.Addition of new computer to the network is easy.

All computer in the network must have good communication and decision making capabilityIf the communication line fails the whole system breaks down.

Ring Topology In Ring topology network , all the computers are connected in closed loop. Each computer on the ring topology network acts as a repeater. It transmit data by passing a token around the network. If the token is free , a computer waiting to send data takes it, attaches the data and the destinations address to the token , and send it . When the token reaches its destination computer, the data is removed.

Ring TopologyAdvantages Disadvantages This network works well where there is no central-site computer systemIf a link between any two computers breaks down, or if one of the computers breaks down , alternate routing is possible.The ring network requires more complicates control software than star network. if one computer fails, the entire network will go down.

Star topologyStar topology is the most popular topology used for networks. In this, each computer is connected to a central device (hub), through an UTP wire. Signals from the sending computer go to the hub and are then transmitted to all the computers in a network. Since each workstation has a separate connection to the hub, it is easy to troubleshoot.

Star TopologyAdvantages Disadvantages Star topology has minimal line cost because only n-1 lines are required for connecting n nodes.If any of the local computers fails, the remaining portion of the network is unaffected.The system crucially depends on central node. If the host computer fails the entire network fails.If traffic between the workstations is high , an undue burden is places on the central node.

Mesh TopologyA mesh topology all the devices in a network are connected to each other with many redundant connection. It provide multiple path for data traveling on the network to reach its destination. Mesh topology also provides redundancy in the network.

Mesh topologyAdvantages DisadvantagesThis type of network is very reliable, as any link breakdown will affect only communication between the connected computers.Communication is very fast between any two nodes.

It is the most expensive network from the point of view of link cost . if there are N nodes in the network, n(n-1)/2 links are required. Hence, the cost of linking the system grows with the square of the number of nodes.

Tree TopologyTree is a network topology containing zero or more nodes that are linked together in a hierarchical fashion. The topmost node is called root. The root may have zero or more child nodes , connected by edges ; the root is the parent node to its children. Each child nod can in turn have zero or more children of its own. Nodes sharing the same parents are called siblings.

Tree TopologyAdvantages Disadvantages Point-to point wiring for individual segments.Supported by several hardware and software companies.

If the backbone line breaks, the entire segment goes down.More difficult to configure and wire than other topologies.

Computer NetworksADVANTAGES

Resource SharingHigh Reliability Saving MoneyScalabilityCommunication MediumIncreased Productivity

Computer NetworkDISADVANTAGES

CrashesData SecurityPrivacy

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