Computer Science UGC Net

HUB Hub is a controller that controls the traffic on the network.  The following important properties of hub are:  1) It amplify signals. 2) It propagates signals through the network. 3) It does not require filtering. 4) It does not require path determination for switching. 5) It is used as network concentration points. Hubs are basically two types: 1) Active hub 2) Passive hub Active hub: A ctive hub works as repeater which is a hardware device that regenerates the received bit pattern before sending them out . Passive hub : A passive hub is a simple hardware device which provide a simple physical connection between the attached devices. Advantages of hub: It cannot filter the traffic full stop feeling generally refers to a process or device that screens network traffic for certain characteristics such as source address and destination address and protocol. Disadvantages of hub: On a hub, more than one user may try to send data on the network at sam

Network Topology The arrangement in which elements like links, nodes of common network are connected is known as network topology. Example of Network topology is found in local area network. We have five types of topologies : 1.) Mesh Topology 2.) Bus Topology 3.) Ring Topology 4.) Star Topology 5.) Hybrid Topology 1.) Mesh Topology : In mesh topology every device is connected with another device via a particular channel. 2.) Bus Topology : The bus topology is used when a network installation is small, simple and temporary. On a typical bus network cable is just one or more wires with no active electronics to amplify the signal or pass it along from computer to computer. This makes the bus a passive topology. Only one computer can send data at one time therefore the number of computers attached to a bus network can significantly affect the speed of the network a computer must wait until the bus is free before it can transmitted. Advantages of bus topology: E

Computer Network means an interconnected collection of autonomous computers. Two computers are said to be interconnected if they're able to exchange information and they use transmission media like copper, fibre optics , microwave etc. Features of Computer Networks : 1) Resource sharing 2) High reliability 3) Saving Money 4) Scalability 5) Communication Medium Uses of Computer networks : 1) For people, video conferencing, person to person communication through computer network. 2) Accessing for remote information 3) For interactive entertainment like video on demand and playing game. 4) It is used for social issues. Data communication: Data communication based transfer data from one point to another and in other words data communication means of transport data from source to destination. The data is transmitted from source to destination through a transmission medium in a form of electromagnetic waves. The transmission medium either guid