This practice paper contains various questions focusing on Communication Channels and Network Devices. It is an important topic for Class XII CBSE Boards Students and through this practice paper they will learn about the various concepts associated with Communication Channels and Network devices easily.
Question : What are Communication Channels in networking?
Answer : A communication channel in networking refers to the physical or logical path used to transmit data between two or more devices in a network. It is the medium through which data travels from the sender to the receiver, and can include wired or wireless transmission media.
Question : What is Wired Communication Channel?
Answer : A wired communication channel refers to a physical medium used to transmit data between devices in a network. These channels use wires or cables to transmit data signals over a physical pathway. Examples of wired communication channels include twisted-pair copper wire, coaxial cable, and fiber optic cable.
| Twisted-pair copper wire is the most common type of wired communication channel and is used for Ethernet networks. This type of cable consists of two conductors twisted together to reduce electromagnetic interference. Twisted-pair cables can be used for short distances, typically up to 100 meters, and offer relatively high speeds and reliability. |  |
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Coaxial cables are typically used for cable television and other high-bandwidth applications. They consist of a central conductor surrounded by an insulating layer and a grounded shield. Coaxial cables can transmit signals over longer distances than twisted-pair cables, up to several kilometers, and offer high bandwidth and good noise resistance. |
| Fiber optic cables are made of thin strands of glass or plastic, which transmit data as light signals. They are used for high-speed, long-distance communications and offer very high bandwidth and low signal loss. Fiber optic cables are commonly used in wide area networks (WANs), such as those connecting different cities or countries. |  |
Question : What are wireless communication channels?
Answer : Wireless communication channels in networking refer to the medium through which data is transmitted without the use of physical wires or cables. Wireless communication channels use electromagnetic waves to transmit data over the airwaves. Examples of wireless communication channels include radio waves, infrared signals, and microwave signals.
Radio waves are commonly used in wireless local area networks (WLANs) and cellular networks. WLANs use Wi-Fi technology to transmit data over radio waves, while cellular networks use radio waves to connect mobile devices to the internet. Radio waves can transmit data over relatively long distances and can penetrate walls and other obstacles, but they can also be affected by interference and signal loss.
Infrared signals are used in short-range wireless communication channels, such as remote control devices, and they transmit data through the air using light waves. Infrared signals are limited in their range and require a clear line of sight between the sender and receiver.
Microwave signals are used for long-range communication channels, such as satellite communication, and can transmit data over vast distances. Microwave signals are also used in microwave ovens, but at a much lower frequency than those used for communication.
Question : What is Bandwidth?
Answer : Bandwidth refers to the maximum amount of data that can be transmitted over a communication channel within a given amount of time, typically measured in bits per second (bps). It is often used to describe the speed or capacity of a network connection or internet service. The higher the bandwidth, the faster the data can be transmitted, which results in faster internet speeds, faster file transfers, and better overall network performance.
Question : What is Baud?
Answer : Baud is a measure of the signaling rate or symbol rate of a communication channel, typically expressed in symbols per second. It represents the number of signal changes (such as voltage or frequency) that can be transmitted over a communication channel in a given amount of time.
Baud rate is used to describe the speed of communication for serial data transmission, which is commonly used in applications such as modems and serial connections between computers and other devices. Baud rate is related to but not the same as the data transfer rate (in bits per second), which is the amount of data that can be transmitted over a communication channel in a given amount of time.
Question : What is Crosstalk (also called bleeding of signals)?
Answer : Crosstalk is an unwanted phenomenon in communication systems where a signal transmitted on one communication channel interferes with a signal on an adjacent channel. This can result in signal distortion or loss, and can significantly impact the performance and reliability of the communication channel. Crosstalk can occur in both wired and wireless communication channels, and can be caused by a variety of factors such as electrical interference, coupling between wires, or proximity of the channels.
Crosstalk is a common problem in telephone systems, where signals from one call can bleed over into adjacent calls, making it difficult to hear and understand the conversation. It can also occur in computer networks, where signals on one wire or cable can interfere with signals on other wires or cables in close proximity
Question : What are the various network devices?
Answer : Here are some common use cases for the following networking devices:
| Modem: Modem stands for MOdulation/DEModulation. A modem is used to connect a computer or network to the internet via a telephone line or cable line. It converts digital signals from the computer into analog signals that can be transmitted over the phone or cable lines, and vice versa. |  |
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Hub: A hub is used to connect multiple devices in a local area network (LAN) to a single network segment. It works by broadcasting all data to all devices connected to it, so it is a simple and inexpensive networking solution, but it can also cause network congestion and collisions. |
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| Switch: A switch is also used to connect multiple devices in a LAN, but it is more advanced than a hub. It can selectively send data only to the intended device, which improves network performance and reduces collisions. |  |
| Repeater: A repeater is used to extend the range of a network by amplifying and re-transmitting signals between network segments. It is often used in wireless networks or to extend the range of wired networks. |  |
| Router: A router is used to connect multiple networks together, such as a LAN and a wide area network (WAN) like the internet. It uses routing tables to direct data packets to their intended destination, and can also provide security features such as firewalls. |  |
| Bridge: A bridge is used to connect two LANs together and allow them to communicate with each other. It operates at the data link layer of the OSI model, and can help reduce network traffic by filtering and forwarding only necessary traffic between the two networks. |  |
| Gateway: A gateway is a device that connects different types of networks, such as a LAN and a WAN, and translates between different network protocols to allow them to communicate with each other. It can be used for security purposes by filtering and blocking unauthorized traffic. |  |
Question : You are setting up a new network for a large office building with several floors, and you are experiencing problems with the signal strength of your network. The signals are becoming weaker the further away from the central router you go, and some areas of the building are experiencing dropped connections or slow data speeds. What device can you use to help improve the signal strength and range of your network, and how can it help solve your problem?
Answer : Repeater
Question : You work for a small business that needs to set up an internet connection for the first time. You have a wired connection from your ISP but need to convert the digital signal to analog so that it can be transmitted over the telephone lines. What device would you use to perform this conversion, and how does it work?
Answer : Modem
Question : You work for a small company that is expanding its network to accommodate more users and devices. You currently have a few computers connected to a hub, but you are experiencing slow speeds and network congestion. You need to upgrade your network to improve performance and accommodate more users. What device would you use to upgrade your network, and how would it help improve performance and reduce network congestion?
Answer : Hub/Switch
Question : You work for a small company that has multiple departments, and each department needs to have its own network with restricted access to other departments. You also need to provide a connection to the internet for all departments. What device would you use to set up these separate networks and control access between them, and how would it work?
Answer: Router
Question: You work for a company that has multiple remote locations, and each location has its own network with different protocols and technologies. You need to connect all these networks to form a single, unified network that can share resources and communicate seamlessly between all locations. What device would you use to accomplish this task, and how would it work to connect these disparate networks?
Answer : Gateway
Question: You work for a company that stores sensitive customer data on its servers, and you need to ensure that the data is protected from unauthorized access or attacks. What device would you use to secure the network and its servers, and how would it work to protect the sensitive data from potential threats?
Answer: Firewall
Question: You work for a company that has two separate networks in different buildings that are physically close to each other, but not connected. You need to connect these networks to share resources and information seamlessly between them, without causing any interference or disruption to either network. What device would you use to connect the two networks, and how would it work to allow communication between them while maintaining their separate identities?
Answer: Bridge
