Networking Devices and Transmission Media | Class 12

Introduction to Networking Device :

A networking device is a hardware component or software application that facilitates communication and data exchange between different computers, devices, or networks. These devices play a crucial role in establishing, managing, and maintaining connections within a network, enabling data to flow efficiently and securely.

There are several types of networking devices, each serving a specific purpose in the functioning of a network. Here are some common types of networking devices and their explanations:

• Router: A router connects different networks together and directs data packets between them. It operates at the network layer (Layer 3) of the OSI model.
• Switch: A switch is used to create a network by connecting devices within the same local area network (LAN). It operates at the data link layer (Layer 2) and forwards data based on MAC addresses.
• Hub: Hubs are basic devices that connect multiple devices in a network, but they operate at the physical layer and do not have the intelligence to manage data traffic efficiently like switches.
• Access Point (AP): An access point is used in wireless networks to provide connectivity to wireless devices like laptops, smartphones, and tablets.
• Firewall: Firewalls are security devices that control incoming and outgoing network traffic based on predefined security rules. They help protect the network from unauthorized access and potential threats.
• Modem: A modem is a device that modulates and demodulates digital data to transmit it over analog communication lines, such as telephone lines or cable systems.

Transmission Media :

Transmission media referred to as communication channels, are the physical pathways through which data, information, and signals travel from one point to another within a network. These media play a critical role in the process of transmitting data between devices, whether over short distances within a local network or across long distances in global communication networks.

There are two main types of transmission media: Guided (bounded) and Unguided (unbounded):

Guided (Bounded) Transmission Media: Guided transmission media use physical conductors to transmit data signals. They provide a direct path for the signals to travel, which makes them more secure and less susceptible to external interference. Here are some types of guided transmission media:

• Twisted Pair Cable: Consists of pairs of insulated copper wires twisted together, often used for telephone and Ethernet connections.

• Coaxial Cable: Features a central conductor surrounded by insulation, a metallic shield, and an outer insulating layer. It’s used for cable television and broadband Internet.

• Optical Fiber Cable: Utilizes light signals transmitted through glass or plastic fibers. It offers high bandwidth, low signal loss, and is commonly used in high-speed data communication.

  

Applications of Guided (Bounded) Transmission Media:

1. Local Area Networks (LANs): Twisted pair cables and coaxial cables are commonly used in LANs to connect computers, printers, and other devices within a limited area.
2. Wide Area Networks (WANs): Optical fiber cables are often used for long-distance connections between different locations in a WAN, providing high-speed data transmission.
3. Cable Television (CATV): Coaxial cables are used to deliver cable TV signals to households, offering a wide range of channels and services.
4. Telephone Lines: Twisted pair cables were traditionally used for telephone lines, although digital technologies like fiber optics and wireless systems are replacing traditional copper lines.
5. Ethernet Connections: Ethernet cables, which include twisted pair and fiber optic options, are used to connect devices within LANs and data centers.

Advantages:

1. Low Signal Loss: Guided media generally have lower signal loss compared to unguided media, making them suitable for long-distance communication.
2. Less Susceptible to Interference: The physical cables used in guided media provide some level of shielding, reducing the susceptibility to external electromagnetic interference.
3. Higher Bandwidth: Certain types of guided media, like optical fiber cables, offer high bandwidth capabilities, allowing for the transmission of large amounts of data.
4. Security: Guided media are less susceptible to eavesdropping and data interception because the signals are confined within the physical cables.

Disadvantages:

1. Physical Limitations: Guided media require physical cables, which can be challenging to install, especially in remote or inaccessible areas.
2. Maintenance Costs: Maintenance of cables can be costly, especially in large-scale networks, as they may require periodic checks, repairs, and replacements.
3. Limited Mobility: Devices using guided media are often constrained by the length of the cable, restricting mobility compared to wireless devices.

Unguided (Unbounded) Transmission Media: Unguided transmission media use wireless signals to transmit data through the air. They provide more mobility and flexibility but are more susceptible to interference. Here are some types of unguided transmission media:

• Radio Waves: Used for wireless communication, including AM/FM radio, Wi-Fi, and cellular networks.
• Microwaves: Employed for long-distance point-to-point communication, such as satellite links and microwave relay systems.
• Infrared Waves: Used for short-range communication, like remote controls and infrared data transmission between devices.
• Light Waves: Including visible light and laser beams, these are used in free-space optical communication and wireless optical communication.

Applications of Unguided (Unbounded) Transmission Media:

1. Cellular Networks: Cellular communication relies on radio waves to enable mobile devices to connect to the internet and make calls, using a network of cell towers.
2. Bluetooth Devices: Bluetooth technology uses radio waves for short-range wireless communication between devices like headphones, speakers, and smartphones.
3. Satellite Communication: Microwaves are used for satellite communication, enabling long-distance transmission of television, internet, and other signals.
4. Radio Broadcasting: Radio waves are used to transmit audio signals for broadcasting radio programs to a wide audience.
5. GPS Navigation: Global Positioning System (GPS) uses signals from satellites to provide accurate location information to navigation devices.

Advantages:

1. Mobility: Wireless devices can communicate without physical cables, enabling easy movement and flexibility.
2. Easy Installation: Rapid and flexible setup without the need for extensive cabling, suitable for changing environments.
3. Scalability: Wireless networks can expand easily to include new devices or areas without additional cables.
4. Flexibility: Ideal for remote or impractical locations, as physical connections aren’t required.

Disadvantages:

1. Interference: Susceptible to electromagnetic and signal interference, leading to data loss or degradation.
2. Signal Weakening: Signals weaken over distance, causing reduced data rates or unreliable connections.
3. Security Risks: Prone to eavesdropping and unauthorized access, raising security concerns.
4. Limited Bandwidth: Some wireless technologies offer limited bandwidth, impacting data transmission speed and capacity.