TASK6
TASK-6
AIM: Demonstrating Importance of Networking, Transmission Media, Networking Devices- Gateway, Routers, Hub, Bridge, NIC, Bluetooth Technology, Wireless Technology, Modem, DSL, and Dialup Connection.
Networking:- Acomputer network is a telecommunications network that allows computers to exchange data.The physical connection between networked computing devices is established using either cable media or wireless media. The best-known computer network is the internet. 2 or more computers that are linked:
1. To share resources
2. Exchange files
3. Allow electronic communications
TYPES OF NETWORKS
A computer network can be categorized by their size. A computer network is mainly of four types:
LAN (Local Area Network)
Local Area Network is a group of computers connected to each other in a small area such as building, office.
LAN is used for connecting two or more personal computers through a communication medium such as twisted pair, coaxial cable, etc.
It is less costly as it is built with inexpensive hardware such as hubs, network adapters, and Ethernet cables.
The data is transferred at an extremely faster rate in Local Area Network.
Local Area Network provides higher security.
PAN (Personal Area Network)
Personal Area Network is a network arranged within an individual person, typically within a range of 10 meters.
Personal Area Network is used for connecting the computer devices of personal use is known as Personal Area Network.
Thomas Zimmerman was the first research scientist to bring the idea of the Personal Area Network.
Personal Area Network covers an area of 30 feet.
Personal computer devices that are used to develop the personal area network are the laptop, mobile phones, media player and play stations.
There are two types of Personal Area Network:
Wired Personal Area Network
Wireless Personal Area Network
Wireless Personal Area Network: Wireless Personal Area Network is developed by simply using wireless technologies such as Wi-Fi, Bluetooth. It is a low range network.
Wired Personal Area Network: Wired Personal Area Network is created by using the USB.
Examples of Personal Area Network:
Body Area Network: Body Area Network is a network that moves with a person.
For example, a mobile network moves with a person. Suppose a person establishes a network connection and then creates a connection with another device to share the information.
MAN (Metropolitan Area Network)
A metropolitan area network is a network that covers a larger geographic area by interconnecting a different LAN to form a larger network.
Government agencies use MAN to connect to the citizens and private industries.
In MAN, various LANs are connected to each other through a telephone exchange line.
The most widely used protocols in MAN are RS-232, Frame Relay, ATM, ISDN, OC-3, ADSL, etc.
It has a higher range than Local Area Network (LAN).
Uses of Metropolitan Area Network:
MAN is used in communication between the banks in a city.
It can be used in an Airline Reservation.
It can be used in a college within a city.
It can also be used for communication in the military
WAN (Wide Area Network)
A Wide Area Network is a network that extends over a large geographical area such as states or countries.
A Wide Area Network is quite bigger network than the LAN.
A Wide Area Network is not limited to a single location, but it spans over a large geographical area through a telephone line, fibre optic cable or satellite links.
The internet is one of the biggest WAN in the world.
A Wide Area Network is widely used in the field of Business, government, and education
Examples of Wide Area Network:
Mobile Broadband: A 4G network is widely used across a region or country
Advantages of Wide Area Network:
Geographical area: A Wide Area Network provides a large geographical area. Suppose if the branch of our office is in a different city then we can connect with them through WAN. The internet provides a leased line through which we can connect with another branch.
Centralized data: In case of WAN network, data is centralized. Therefore, we do not need to buy the emails, files or back up servers.
Get updated files: Software companies work on the live server. Therefore, the programmers get the updated files within seconds.
What is Topology?
Topology defines the structure of the network of how all the components are interconnected to each other.
Bus Topology
The bus topology is designed in such a way that all the stations are connected through a single cable known as a backbone cable.
Each node is either connected to the backbone cable by drop cable or directly connected to the backbone cable.
When a node wants to send a message over the network, it puts a message over the network. All the stations available in the network will receive the message whether it has been addressed or not.
The bus topology is mainly used in 802.3 (Ethernet) and 802.4 standard networks.
The configuration of a bus topology is quite simpler as compared to other topologies.
The backbone cable is considered as a "single lane" through which the message is broadcast to all the stations.
The most common access method of the bus topologies is CSMA (Carrier Sense Multiple Access).
Advantages of Bus topology:
Low-cost cable: In bus topology, nodes are directly connected to the cable without passing through a hub. Therefore, the initial cost of installation is low.
Moderate data speeds: Coaxial or twisted pair cables are mainly used in bus-based networks that support up to 10 Mbps.
Moderate data speeds: Coaxial or twisted pair cables are mainly used in bus-based networks that support up to 10 Mbps.
Disadvantages of Bus topology:
Extensive cabling: A bus topology is quite simpler, but still it requires a lot of cabling.
Signal interference: If two nodes send the messages simultaneously, then the signals of both the nodes collide with each other.
Reconfiguration difficult: Adding new devices to the network would slow down the network.
Ring Topology
Ring topology is like a bus topology, but with connected ends.
The node that receives the message from the previous computer will retransmit to the next node.
The data flows in one direction, i.e., it is unidirectional.
The data flows in a single loop continuously known as an endless loop.
It has no terminated ends, i.e., each node is connected to other node and having no termination point.
The data in a ring topology flow in a clockwise direction.
The most common access method of the ring topology is token passing.
Token passing: It is a network access method in which token is passed from one node to another node.
Token: It is a frame that circulates around the network.
Advantages of Ring topology:
Network Management: Faulty devices can be removed from the network without bringing the network down.
Cost: Twisted pair cabling is inexpensive and easily available. Therefore, the installation cost is very low.
Reliable: It is a more reliable network because the communication system is not dependent on the single host computer.
Disadvantages of Ring topology:
Difficult troubleshooting: It requires specialized test equipment to determine the cable faults. If any fault occurs in the cable, then it would disrupt the communication for all the nodes.
Failure: The breakdown in one station leads to the failure of the overall network.
Reconfiguration difficult: Adding new devices to the network would slow down the network.
Delay: Communication delay is directly proportional to the number of nodes. Adding new devices increases the communication delay.
Star Topology
Star topology is an arrangement of the network in which every node is connected to the central hub, switch or a central computer.
The central computer is known as a server, and the peripheral devices attached to the server are known as clients.
Coaxial cable or RJ-45 cables are used to connect the computers.
Hubs or Switches are mainly used as connection devices in a physical star topology.
Star topology is the most popular topology in network implementation.
Advantages of Star topology
Efficient troubleshooting: Troubleshooting is quite efficient in a star topology as compared to bus topology. In a bus topology, the manager has to inspect the kilometres of cable. In a star topology, all the stations are connected to the centralized network. Therefore, the network administrator has to go to the single station to troubleshoot the problem
Limited failure: As each station is connected to the central hub with its own cable, therefore failure in one cable will not affect the entire network.
Familiar technology: Star topology is a familiar technology as its tools are cost-effective.
Easily expandable: It is easily expandable as new stations can be added to the open ports on the hub.
Cost effective: Star topology networks are cost-effective as it uses inexpensive coaxial cable.
Disadvantages of Star topology
A Central point of failure: If the central hub or switch goes down, then all the connected nodes will not be able to communicate with each other.
Tree topology
Tree topology combines the characteristics of bus topology and star topology.
A tree topology is a type of structure in which all the computers are connected with each other in hierarchical fashion.
The top-most node in tree topology is known as a root node, and all other nodes are the descendants of the root node.
There is only one path exists between two nodes for the data transmission. Thus, it forms a parent-child hierarchy.
Advantages of Tree topology
Support for broadband transmission: Tree topology is mainly used to provide broadband transmission, i.e., signals are sent over long distances without being attenuated.
Easily expandable: We can add the new device to the existing network. Therefore, we can say that tree topology is easily expandable.
Easily manageable: In tree topology, the whole network is divided into segments known as star networks which can be easily managed and maintained.
Error detection: Error detection and error correction are very easy in a tree topology.
Limited failure: The breakdown in one station does not affect the entire network.
Point-to-point wiring: It has point-to-point wiring for individual segments.
Disadvantages of Tree topology
Difficult troubleshooting: If any fault occurs in the node, then it becomes difficult to troubleshoot the problem.
High cost: Devices required for broadband transmission are very costly.
Failure: A tree topology mainly relies on main bus cable and failure in main bus cable will damage the overall network.
Mesh topology
Mesh technology is an arrangement of the network in which computers are interconnected with each other through various redundant connections.
There are multiple paths from one computer to another computer.
It does not contain the switch, hub or any central computer which acts as a central point of communication.
The Internet is an example of the mesh topology.
Mesh topology is mainly used for WAN implementations where communication failures are a critical concern.
Mesh topology is mainly used for wireless networks.
Mesh topology can be formed by using the formula:
Number of cables = (n*(n-1))/2;
Where n is the number of nodes that represents the network.
Advantages of Mesh topology:
Reliable: The mesh topology networks are very reliable as if any link breakdown will not affect the communication between connected computers.
Fast Communication: Communication is very fast between the nodes.
Easier Reconfiguration: Adding new devices would not disrupt the communication between other devices.
Disadvantages of Mesh topology
Cost: A mesh topology contains a large number of connected devices such as a router and more transmission media than other topologies.
Management: Mesh topology networks are very large and very difficult to maintain and manage. If the network is not monitored carefully, then the communication link failure goes undetected.
Efficiency: In this topology, redundant connections are high that reduces the efficiency of the network.
Hybrid Topology
The combination of various different topologies is known as Hybrid topology.
A Hybrid topology is a connection between different links and nodes to transfer the data.
When two or more different topologies are combined together is termed as Hybrid topology and if similar topologies are connected with each other will not result in Hybrid topology. For example, if there exist a ring topology in one branch of ICICI bank and bus topology in another branch of ICICI bank, connecting these two topologies will result in Hybrid topology.
Advantages of Hybrid Topology
Reliable: If a fault occurs in any part of the network will not affect the functioning of the rest of the network.
Scalable: Size of the network can be easily expanded by adding new devices without affecting the functionality of the existing network.
Flexible: This topology is very flexible as it can be designed according to the requirements of the organization.
Effective: Hybrid topology is very effective as it can be designed in such a way that the strength of the network is maximized and weakness of the network is minimized.
Disadvantages of Hybrid topology
Complex design: The major drawback of the Hybrid topology is the design of the Hybrid network. It is very difficult to design the architecture of the Hybrid network.
Costly Hub: The Hubs used in the Hybrid topology are very expensive as these hubs are different from usual Hubs used in other topologies.
Costly infrastructure: The infrastructure cost is very high as a hybrid network requires a lot of cabling, network devices, etc.
What is Transmission media?
Transmission media is a communication channel that carries the information from the sender to the receiver. Data is transmitted through the electromagnetic signals.
It is a physical path between transmitter and receiver in data communication.
In OSI (Open System Interconnection) phase, transmission media supports the Layer 1. Therefore, it is considered to be as a Layer 1 component.
Transmission media is of two types are wired media and wireless media. In wired media, medium characteristics are more important whereas, in wireless media, signal characteristics are more important.
The transmission media is available in the lowest layer of the OSI reference model, i.e., Physical layer.
Classification of Transmission Media:
Network Devices:
Hardware devices that are used to connect computers, printers, fax machines and other electronic devices to a network are called network devices.
Modems
Modem is a device that enables a computer to send or receive data over telephone or cable lines. The data stored on the computer is digital whereas a telephone line or cable wire can transmit only analog data.
The main function of the modem is to convert digital signal into analog and vice versa. Modem is a combination of two devices − modulator and demodulator. The modulator converts digital data into analog data when the data is being sent by the computer. The demodulator converts analog data signals into digital data when it is being received by the computer.
Types of Modem:
Modem can be categorized in several ways like direction in which it can transmit data, type of connection to the transmission line, transmission mode, etc.
Depending on direction of data transmission, modem can be of these types −
Simplex − A simplex modem can transfer data in only one direction, from digital device to network (modulator) or network to digital device (demodulator).
Half duplex − A half-duplex modem has the capacity to transfer data in both the directions but only one at a time.
Full duplex − A full duplex modem can transmit data in both the directions simultaneously.
HUB:
A network hub is a multiport repeater that connects multiple wires from different branches. It is used to transfer important data and communicate among diverse network hosts. Hub works on physical layer of OSI model layer.
When a data frame arrives at a port, it is broadcast to every other port with out considering whether it is destined for a particular destination device or not.
Hubs cannot filter data, so data packets are sent to all connected devices.
Hub does not store any MAC or IP address to transfer data.
It works in half duplex. Only one device can send data at a time.
Switch
Switch is a network device that connects other devices to Ethernet networks through twisted pair cables. It uses packet switching technique to receive, store and forward data packets on the network. The switch maintains a list of network addresses of all the devices connected to it.
It works in a data link layer of OSI model.
On receiving a packet, it checks the destination address and transmits the packet to the correct port. Before forwarding, the packets are checked for collision and other network errors. The data is transmitted in full duplex mode.
When data frame arrives at any port of network switch ,first it examines the destination address and sends that frames to corresponding device.
Routers:
Router works in Network layer of OSI model.
Router is a routing device use to create route for transmitting data packets.
Router is used to connect two or more different network.
Router connects different networks together and sends the data packets from one network to another network.
Router can be used both LANs and WANs.
It transfer the data in the form of IP packets. In order to transmit data , it uses IP address mentioned in the destination field of the IP packets.
Routers more expensive than Hubs and Bridges and switches.
Bridge – A bridge operates at the data link layer. A bridge is a repeater, with add on the functionality of filtering content by reading the MAC addresses of the source and destination. It is also used for interconnecting two LANs working on the same protocol. It has a single input and single output port, thus making it a 2 port device.
Gateways:
Gateway is a network device used to connect two or more dissimilar networks. In networking parlance, networks that use different protocols are dissimilar networks. A gateway usually is a computer with multiple NICs connected to different networks. A gateway can also be configured completely using software. As networks connect to a different network through gateways, these gateways are usually hosts or end points of the network.
Bluetooth
Bluetooth technology is a short-range wireless communications technology to replace the cables connecting electronic devices, allowing a person to have a phone conversation via a headset, use a wireless mouse and synchronize information from a mobile phone to a PC, all using the same core system.
DSL
Digital Subscriber Line (DSL) is a technology that provides digital data transmission over the existing wires of local telephone network.
DSL service is delivered simultaneously with regular telephone on the same telephone line.
This is possible because DSL uses a higher frequency.
Digital Subscriber Line (DSL) is a broadband high-speed Internet technology that brings high-band width information to home and offices over ordinary copper telephone lines.
Digital data is transmitted directly to the computer, asis, exploiting the maximum band width and the wide range of unused frequencies available in the existing copper wire of telephone networks for high-speed broad band communication.
DSL service is always ON and we can still use the phone for voice calls. Broad band speed is much faster than dial up service.
•Fixed monthly billing, regard less of time usage.
•Digital data is directly transmitted to computer as digital data which uses much wider band width fortransmitting.DSL has one significant down side:
As you move away from the central office, the connection becomes slower. This result is distortion of signal.
DIAL-UP CONNECTION
A dial-up connection is established when two or more communication devices use a public switched telephone network (PSTN) to connect to an Internet service provider (ISP).
Many remote areas depend on Internet dial-up connections because broadband and cable are rare in remote areas with low population numbers.
Setting up dial-up Internet in Windows 7
Click the Network Connection icon (lower right corner of your computer screen).
Click Open Network and Sharing Centre.
Click set up a new connection or network.
4.Click Set up a dial-up connection, then click Next.
5.Enter your settings for dial-up Internet
6.Click Connect. If it works, your login settings will be saved automatically.
To disconnect or reconnect to the Internet:
Click the Network Connection icon (lower right corner of your computer screen).
Choose Dial up Connection and click either Disconnect or Connect.
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