PowerPoint Presentation

SEMINAR TOPICON NETWORK AND NETWORKING DEVICES

CONTENTSNetworkAdvantages of Computer NetworkingDisadvantages of Computer NetworkingTransmission Modes in Computer NetworksDifferent Types of NetworksNetwork DevicesNetwork topology

NETWORKA computer network is a telecommunications network which allows computers to exchange data. In computer networks, networked computing devices exchange data with each other using a data link. The connections between nodes are established using either cable media or wireless media. The best-known computer network is the Internet.

Advantages of Computer Networking

1. It enhances communication and availability of information.2. It allows for more convenient resource sharing.3. It makes file sharing easier.4. It is highly flexible.5. It is an inexpensive system6. It increases cost efficiency.7. It boosts storage capacity.

Disadvantages of Computer Networking

1.It lacks independence.2. It poses security difficulties.3. It lacks robustness.4. It allows for more presence of computer viruses and malware.5. Its light policing usage promotes negative acts.6. It requires an expensive set-up.

Transmission Modes in Computer Networks

Transmission mode means transferring of data between two devices. It is also called communication mode. These modes direct the direction of flow of information. There are three types of transmission mode. They are :1.Simplex Mode2.Half duplex Mode3.Full duplex Mode

Simplex Mode

In this type of transmission mode data can be sent only through one direction i.e. communication is unidirectional. We cannot send a message back to the sender. Unidirectional communication is done in Simplex Systems.Examples of simplex Mode is loudspeaker, television broadcasting, television and remote, keyboard and monitor etc.

Half Duplex ModeIn half duplex system we can send data in both directions but it is done one at a time that is when the sender is sending the data then at that time we cant send the sender our message. The data is sent in one direction.Example of half duplex is a walkie- talkie in which message is sent one at a time and messages are sent in both the directions.

Full Duplex Mode

In full duplex system we can send data in both directions as it is bidirectional. Data can be sent in both directions simultaneously. We can send as well as we receive the data.Example of Full Duplex is a Telephone Network in which there is communication between two persons by a telephone line, through which both can talk and listen at the same time.

Different Types of NetworksThere are many ways in which different networks can be classified, such as their size, capabilities and the geographical distance they cover. A network is simply a group of two or more computer systems linked together in some way so that they can share data between them.1. Local Area Network (LAN)2. Wide Area Network (WAN)3. Metropolitan Area Network(MAN)

Local Area Network (LAN)

This is one of the original categories of network, and one of the simplest.LAN networks connect computers together over relatively small distances, such as within a single building or within a small group of buildings. Homes often have LAN networks too, especially if there is more than one device in the home. Often they do not contain more than one subnet, if any, and are usually controlled by a single administrator.

Wide Area Network (WAN)

This is another of the original categories of network, and slightly more complex in nature. WAN networks connect computers together over large physical distances, remotely connecting them over one huge network and allowing them to communicate even when far apart. The Internet is a WAN, and connects computers all around the world together. LANs connect to WANs, such as the internet, using routers to transfer data and information quickly and securely.

Metropolitan Area Network(MAN)

This is a network which is larger than a LAN but smaller than a WAN, and incorporates elements of both. It typically connect a town or city and is owned by a single person or company, such as a local council or a large company.

Network DevicesNIC(Network Interface Card)HUBBridgeSwitchesRoutersCables

NIC(Network Interface Card)

Network cards also known as Network Interface Cards (NICs) are hardware devices that connect a computer with the network. They are installed on the mother board. They are responsible for developing a physical connection between the network and the computer. Computer data is translated into electrical signals send to the network via Network Interface Cards. They can also manage some important data-conversion function.

HUBHub is one of the basic icons of networking devices which works at physical layer and hence connect networking devices physically together. Hubs are fundamentally used in networks that usetwisted pair cablingto connect devices. They are designed to transmit the packets to the other appended devices without altering any of the transmitted packets received. They act as pathways to direct electrical signals to travel along. They transmit the information regardless of the fact if data packet is destined for the device connected or not.

Bridge

A bridge is a computer networking device that builds the connection with the other bridge networks which use the same protocol. It connects two local-area networks; two physical LANs into larger logical LAN or twosegmentsof the same LAN that use the same protocol. Apart from building up larger networks, bridges are also used to segment larger networks intosmallerportions. The bridge does so by placing itself between the two portions of two physical networks and controlling the flow of the data between them. Bridges nominate to forward the data after inspecting into the MAC address of the devices connected to every segment.

Switches

Just as in hub, devices in switches are connected to them through twisted pair cabling. But the difference shows up in the manner both the devices; hub and a switch treat the data they receive.Hub works by sending the data to all the ports on the device whereas aswitchtransfers it only to that port which is connected to the destination device. A switch does so by having an in-built learning of the MAC address of the devices connected to it. Switches operate infull-duplexmode where devices can send and receive data from the switch at the simultaneously unlike in half-duplex mode.

Routers

Routers are network layer devices and are particularly identified as Layer- 3 devices of the OSI Model. They processlogicaladdressing information in the Network header of a packet such as IP Addresses. Router is used to create larger complex networks by complex traffic routing. It has the ability to connect dissimilar LANs on the same protocol.A router primarily comprises of a hardware device or a system of the computer which has more than one network interface and routing software.

Cables Cablesarenetworking hardwareused to connect one network device to other network devices or to connect two or more computers to shareprinters,scannersetc. Different types of network cables, such ascoaxial cable,optical fiber cable, andtwisted pair cables, are used depending on the network'sphysical layer,topology, and size.

Network topology

Network topology is the arrangement of the various elements (links,nodes, etc.) of acomputer network.Essentially, it is the topologicalstructure of a network and may be depicted physically or logically. The cabling layout used to link devices is the physical topology of the network.The physical topology of a network is determined by the capabilities of the network access devices and media, and the cost associated with cabling or telecommunications circuits.Topology can be classified asBus topologyStar topologyRing topologyMesh topology

Bus topology

In local area networks where bus topology is used, each node is connected to a single cable, by the help of interface connectors. This central cable is the backbone of the network and is known as the bus . 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. Because the bus topology consists of only one wire, it is rather inexpensive to implement when compared to other topologies.

Star topology

In local area networks with a star topology, each network host is connected to a central hub with a point-to-point connection. So it can be said that every computer is indirectly connected to every other node with the help of the hub. In Star topology, every node (computer workstation or any other peripheral) is connected to a central node called hub, router or switch. The switch is the server and the peripherals are the clients.Nodes on the network must be connected to one central device.

Ring topology

A ring topology is a bus topology in a closed loop. 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 destination.Each device in ring incoperates a repeater. It is easy to install and reconfigure.

Mesh topology

Every device has a dedicated point to point link to every other device.The term dedicated means the link carries traffic between only two devices it connects.To find no of physical links in fully connected mesh network with n nodes.we need (n-1) physical links.It allows communication in both direction.