Computer networking devices

Computer networking devices are hardware components that enable computers and other devices to communicate and share resources. These devices are essential for establishing and maintaining wired or wireless networks. Each device plays a unique role in ensuring data is transmitted accurately and efficiently.

Types of Computer Networking Devices

1. Hubs

• A hub is a basic networking device that connects multiple devices in a LAN. It broadcasts incoming data to all connected devices, which can lead to inefficiencies. While switches have largely replaced hubs, they remain important to networking history.
• Hub is a very simple network connecting device. In Star/hierarchical topology, a Repeater is called a Hub. It is also known as a Multiport Repeater Device.
• A Hub operates only in the physical network of the OSI Model. Since it works in the physical layer, it mainly deals with the data in the form of bits or electrical signals. A Hub is mainly used to create a network and connect devices on the same network only.
• A Hub is not an intelligent device, it forwards the incoming messages to other devices without checking for any errors or processing it. It does not maintain any address table for connected devices. It only knows that a device is connected to one of its ports.

There are mainly two types of Hub, they are:

1. Active Hub: An Active hub is also known as a Concentrator. It requires a power supply and can work as a repeater. Thus, it can analyze the data packets and amplify the transmission signals, if needed.
2. Passive Hub: A passive hub does not need any power supply to operate. It only provides communication between the networking devices and does not amplify the transmission signals. In other words, it just forwards the data as it is.

The following are the advantages of using a Hub:

1. It is simple to implement.
2. The implementation cost is low.
3. It does not require any special system administration configuration. We can just plug and play it.

The following are the disadvantages of using a Hub:

1. It can connect devices of the same network only.
2. It uses a half-duplex mode of communication.
3. It is less secure, as it broadcasts the data packets.
4. It can be used in a limited network size only.
5. Broadcasting induces unnecessary traffic on the channel.

2. Bridges

A bridge connects two or more networks, allowing them to function as a single network. It reduces traffic by dividing networks into smaller, more manageable segments.

There are mainly two types of Bridge, they are:

1. Transparent Bridge: Transparent bridge simply works as a transmission medium between two devices. They are actually transparent(they are present but are not functionally visible to the devices) to the networking devices.
2. Routing Bridge: Routing bridges have their unique identity, they can be easily identified by the network devices. The source station or the sender can send the data packets through specific bridges(using the unique identity of bridges).

The following are the advantages of using a Bridge:

1. It is not so complex to implement.
2. The implementation cost is medium.
3. It does not require any special system administration configuration. We can just plug and play it.
4. Improves security by limiting the scope of data frames.
5. It has the filtering capability.
6. It can be used in a large network.

The following are the disadvantages of using a Bridge:

1. It can connect devices of the same network only.
2. There is a delay in forwarding the frames due to error checking.
3. There is a need to maintain an Address table.

3. Switches

• Switches are used within local area networks (LANs) to connect multiple devices, such as computers, printers, and servers. Unlike hubs, switches intelligently forward data to the intended recipient, ensuring efficient network performance.

There are mainly four types of Switches, they are:

1. Store and Forward Switch: It is the most widely and commonly used switch. It does not forward the data frames unless the frames are errorless and completely received in the switch buffer. It is reliable in nature.
2. Cut-through Switch: Cut-through switches have no error checking. Also, it starts sending the data frame to the destination node when it starts receiving it. It is unreliable in nature.
3. Fragment-Free Switch: It is a combination of store and forward, and cut-through switches. It checks only the starting 64 bytes(header information) of the data frame before transmitting the frame.
4. Adaptive Switch: It is the most advanced kind of switch, which automatically chooses any of the above three switches as per the need.

The following are the advantages of using a Switch:

1. The implementation cost is medium.
2. It does not require any special system administration configuration. We can just plug and play it.
3. Improves security by limiting the scope of data frames.
4. It has the filtering capability.
5. It can be used in a large network.
6. It uses full-duplex mode of communication
7. It has multiple collision domains, so there are least or no collisions in the channel.

The following are the disadvantages of using a Switch:

1. It can connect devices of the same network only.
2. There is a delay in forwarding the frames due to error checking.
3. There is a need to maintain a Switch table.

4. Routers

Routers are pivotal devices that connect multiple networks and direct data packets to their destination. They are commonly used to link home or office networks to the internet. Routers operate using IP addresses and protocols to ensure data is routed efficiently.it works on the physical, data-link, and network layer of the OSI model. It is mainly an internetworking device, which can connect devices of different networks(implementing the same architecture and protocols).

A Router can be a Wireless Router, Core Routers, edge router, a virtual router, etc.

There are mainly two types of routing performed by Routers, they are:

1. Static Routing: In Static Routing, the path for the data packets is manually set. It is generally used for small networks.
2. Dynamic Routing: In Dynamic Routing, various routing algorithms are used to find the best and shortest path for the data packets.

The following are the advantages of using a Router:

1. It can connect devices and provide routing facilities over different networks implementing the same protocol and structure.
2. Improves security by limiting the scope of data packets.
3. It has the filtering capability.
4. It can be used in a large network.
5. It uses full-duplex mode of communication
6. It has control over both the collision and broadcast domains.

The following are the disadvantages of using a Router:

1. It is very complex to implement.
2. The implementation cost is quite high.
3. There is a need to maintain a Routing table.
4. There is a delay in forwarding the packets due to error checking.
5. It requires a special system administration configuration.

5. Gateways

Gateways act as entry points between different networks. They enable communication between systems with different protocols, ensuring compatibility and data integrity.

A Gateway is the most intelligent device among network connecting devices, offering advanced functionality for error control, data packet routing, transmission speed, and overall operation. It serves as a crucial component in connecting different networks, often with varying protocols and architectures. A Gateway is also referred to as a “Protocol Converter” because of its ability to convert data packets to match the protocol requirements of the destination network. This functionality is crucial when connecting networks that operate on different communication protocols.

The following are the advantages of using a Gateway:

1. It can connect the devices of two different networks having dissimilar structures.
2. It is an intelligent device with filtering capabilities.
3. It has control over both collisions as well as a broadcast domain.
4. It uses a full-duplex mode of communication.
5. It has the fastest data transmission speed among all network-connecting devices.
6. It can perform data translation and protocol conversion of the data packet as per the destination network’s need.
7. It can encapsulate and decapsulate the data packets.
8. It has improved security than any other network connecting device.

The following are the disadvantages of using a Gateway:

1. It is complex to design and implement.
2. The implementation cost is very high.
3. It requires a special system administration configuration.

6. Modems

Modems (short for modulator-demodulator) are devices that connect a network to the internet by converting digital signals to analog and vice versa. They are essential for accessing internet services via broadband or DSL connections.Based on the differences in speed and transmission rate, a modem can be classified into the following categories:

• • Standard PC modem or Dial-up modem
  • Cellular Modem
  • Cable modem 

What is Transmission Media?

Transmission media refer to the physical pathways that carry data from one point to another in a network. These media can be wired or wireless, depending on the application and environment.

Importance of Transmission Media in Communication

Classification of Transmission Media

Guided Media

It is defined as the physical medium through which the signals are transmitted. It is also known as Bounded media.

Types Of Guided Media:

1. Twisted Pair Cables

are one of the most commonly used types of cables in networking and telecommunications. They consist of pairs of insulated copper wires twisted together, which helps reduce interference and improve signal quality.

fig. Twisted pair cables.

Here are the advantages of twisted pair cables:

1. Cost-Effective: Twisted pair cables are inexpensive compared to other transmission media like coaxial or fiber optic cables.
2. Easy Installation: They are lightweight, flexible, and simple to install.
3. Wide Availability: Twisted pair cables are commonly available and used in various network setups.
4. Noise Reduction: The twisted design minimizes electromagnetic interference and crosstalk.
5. Scalability: They are suitable for short- to medium-distance communication and can be easily upgraded or extended.
6. Durability: The cables are robust enough for standard use and can withstand bending without damage.
7. Support for Analog and Digital Signals: Twisted pair cables can efficiently carry analog and digital signals.
8. Compatibility: These cables are widely supported by various networking and telecommunication devices.

Types of Twisted pair:

1.Unshielded Twisted Pair (UTP)

Unshielded Twisted Pair (UTP) is a type of cable commonly used in telecommunications and computer networking. It consists of pairs of copper wires twisted together to reduce electromagnetic interference and crosstalk between adjacent pairs. UTP cables do not have an additional shielding layer, making them lightweight, flexible, and cost-effective.

Advantages Of Unshielded Twisted Pair:

• It is cheap.
• Installation of the unshielded twisted pair is easy.
• It can be used for high-speed LAN.

Disadvantage:

• This cable can only be used for shorter distances because of attenuation.

Shielded Twisted Pair (STP)

Shielded Twisted Pair (STP) is a type of twisted-pair cable that features an additional shielding layer around the pairs of wires to protect against electromagnetic interference (EMI) and crosstalk. This shielding can be made of a metallic foil, braided wire, or both, providing extra protection in environments with high levels of interference.

Characteristics of Shielded Twisted Pair (STP)

1. Shielding Layer: STP cables have a protective layer of metal shielding, which helps reduce interference from external electromagnetic signals.
2. Better Signal Quality: The shielding ensures better signal integrity by minimizing noise and crosstalk between adjacent wires.
3. Thicker and Heavier: The additional shielding makes STP cables thicker and heavier than unshielded twisted pair (UTP) cables.
4. Higher Cost: Due to the shielding material and more complex manufacturing process, STP cables are generally more expensive than UTP cables.
5. Requires Proper Grounding: For effective performance, STP cables need proper grounding to ensure the shield can dissipate unwanted interference.
6. Less Flexible: The added shielding makes the cable less flexible, which can complicate installation in tight or complex spaces.
7. Improved Performance in High-Interference Environments: STP cables are well-suited for environments with significant electromagnetic interference, such as factories, industrial settings, or areas with heavy electrical equipment.
8. Compatibility with Networking Standards: Modern STP cables are compatible with high-speed networking standards, such as Gigabit Ethernet, while offering enhanced protection against interference.
9. Lower Crosstalk: The shielding reduces the impact of crosstalk, which is the interference between cable pairs, resulting in better overall performance.

Disadvantages

• It is more expensive as compared to UTP and coaxial cable.It has a higher attenuation rate.

Coaxial Cable

• Definition: A coaxial cable is a commonly used transmission medium, often seen in applications like television connections.
• It is called “coaxial” because it contains two conductors that are parallel to each other.
• Coaxial cables operate at a higher frequency than twisted pair cables, making them suitable for high-speed data transfer applications.

Structure of Coaxial Cable:

1. Inner Conductor:
   • Made of copper and is responsible for carrying the data signals.
2. Non-Conductive Cover:
   • Surrounds the inner conductor to provide insulation and separation from the outer conductor.
3. Outer Conductor:
   • Made of copper mesh or foil, which acts as a shield to prevent electromagnetic interference (EMI).
4. Outer Jacket:
   • A protective covering that provides durability and physical protection for the cable.

Coaxial cable is of two types:

1. Baseband transmission: It is defined as the process of transmitting a single signal at high speed.
2. Broadband transmission: It is defined as the process of transmitting multiple signals simultaneously.

Advantages Of Coaxial Cable:

• The data can be transmitted at high speed.
• It has better shielding than twisted pair cables.It provides higher bandwidth.
• Disadvantages Of Coaxial Cable:
  • It is more expensive than twisted pair cables.
  • If any fault occurs in the cable causes the failure in the entire network.

Optical Fiber: 

Optical fiber is a modern transmission medium used to send data in the form of light signals. It is made of very thin strands of glass or plastic called fibers. These fibers carry information over long distances at very high speeds. Optical fiber provides a very high data transmission speed compared to copper cables. Because data travels as light, it can transmit large amounts of information, such as voice, video, and internet data, quickly and efficiently.One important feature of optical fiber is low signal loss. Light signals can travel long distances without losing much strength, so fewer repeaters are needed. This makes it ideal for long-distance communication.

Optical fiber is free from electromagnetic interference. Unlike copper wires, it is not affected by electrical noise, weather conditions, or magnetic fields. This ensures clear and secure communication.Another advantage of optical fiber is high security. It is difficult to tap or intercept light signals, making it safer for transmitting sensitive information.

In conclusion, optical fiber is a reliable and high-speed transmission medium widely used in internet connections, telephone networks, cable TV, and long-distance communication systems

Structure of Optical Fiber

An optical fiber is made up of several layers. Each layer has an important role in transmitting light signals efficiently.

1. Core
The core is the central part of the optical fiber. It is made of glass or plastic and carries the light signals. Data travels through the core in the form of light pulses.

2. Cladding
The cladding surrounds the core. It is made of glass with a lower refractive index than the core. The cladding reflects the light back into the core, allowing the light to travel long distances using total internal reflection.

3. Coating (Buffer Layer)
The coating or buffer layer protects the core and cladding from physical damage, moisture, and bending. It is usually made of plastic.

4. Jacket (Outer Cover)
The jacket is the outermost layer of the optical fiber. It provides extra protection from environmental damage such as heat, water, and pressure.

5. Strength Members (Optional)
Some optical fiber cables include strength members (like Kevlar) between the coating and jacket. These help the cable withstand pulling and stretching during installation.

Unguided Media

Unguided media is a type of transmission media that sends data without using physical cables or wires. In this media, signals travel through the air or space in the form of electromagnetic waves. It is also known as wireless transmission media.

Unguided media is widely used because it allows mobility and flexibility. Devices can communicate with each other even when they are moving, such as mobile phones, laptops, and tablets.

Types of Unguided Media: 

1. Radio Waves

Radio waves are a type of electromagnetic wave that are widely used for communication over short, medium, and long distances. They have long wavelengths and low frequencies, which allows them to travel far and cover large areas. One important property of radio waves is that they can pass through walls, buildings, and even the Earth’s atmosphere without much loss of energy.

Radio waves are commonly used in radio and television broadcasting to send audio and video signals from stations to receivers. They are also used in Wi-Fi networks, where they help connect devices like smartphones, laptops, and tablets to the internet without using wires. In addition, mobile phones use radio waves to communicate with nearby cell towers, making wireless calls and data transfer possible.

Advantages of Radio Waves

• Radio waves can travel long distances, which makes them very useful for communication over large areas such as cities, countries, and even across continents.
• They can pass through walls, buildings, and obstacles, so they are ideal for indoor communication like Wi-Fi and mobile networks.
• Radio waves are used for wireless communication, so there is no need for physical cables, which reduces installation cost and complexity.
• They are safe for humans because they are non-ionizing and do not damage body cells.
• Radio waves support many technologies such as radio broadcasting, television, mobile phones, Wi-Fi, Bluetooth, and satellite communication.

Disadvantages of Radio Waves

• Radio waves can be affected by interference from other electronic devices, weather conditions, or nearby signals, which can reduce signal quality.
• The data transmission speed of radio waves is generally lower compared to other waves like microwaves or optical fibers.
• Radio wave communication can be less secure because signals can be intercepted by unauthorized users if not properly encrypted.
• Obstacles like tall buildings, mountains, or dense structures can weaken or block radio wave signals.
• Limited frequency spectrum availability can cause congestion when many devices use the same radio frequencies.

Applications of Radio Waves

• Radio waves are used to transmit sound signals in AM and FM radio broadcasting. People can listen to news, music, and programs over long distances using radio receivers.
• Radio waves carry audio and video signals from television stations to TV sets, especially in terrestrial TV broadcasting.
• Mobile phones use radio waves to communicate with nearby cell towers. This allows voice calls, video calls, text messages, and internet access.
• Radio waves are used in Wi-Fi networks to connect devices such as laptops, smartphones, and tablets to the internet without using cables.
• Radio waves are used to send signals between Earth and satellites for GPS, weather forecasting, television services, and global communication.
• Bluetooth technology uses radio waves to connect devices like wireless headphones, keyboards, speakers, and smartwatches over short distances.
• Radio waves are used in aircraft communication, air traffic control, and navigation systems to ensure safe travel.
• Radio waves are used by police, hospitals, rescue teams, and the military for fast and reliable communication during emergencies.

Microwaves

Microwaves are a type of electromagnetic wave with shorter wavelengths and higher frequencies than radio waves. They are mainly used for high-speed communication and heating purposes. Microwaves travel in straight lines and cannot easily pass through buildings, so they require a clear line of sight between the transmitter and receiver.

Microwaves are widely used in satellite communication, mobile networks, and radar systems. They are also used in microwave ovens to heat and cook food by causing water molecules to vibrate and produce heat. Because microwaves can carry large amounts of data, they play an important role in modern wireless communication.

Advantages of Microwaves

1. Microwaves support high data transmission speed, making them suitable for modern communication systems.
2. They are ideal for satellite and long-distance communication.
3. Microwaves can carry more information due to their high frequency.
4. They are widely used in radar systems for navigation and weather monitoring.
5. Microwave antennas are smaller in size compared to radio wave antennas.

Disadvantages of Microwaves

1. Microwaves require a line-of-sight, so obstacles like buildings and hills can block the signal.
2. Weather conditions such as rain and fog can weaken microwave signals.
3. High-power microwaves can be harmful to living tissues if not properly controlled.
4. Setting up microwave communication systems can be costly.
5. Signal loss may occur over long distances without repeaters.

Applications of Microwaves

1. Microwave Ovens
Microwaves are widely used in microwave ovens to cook and heat food quickly. The microwave radiation makes water molecules inside the food vibrate, which produces heat. This process cooks food evenly and saves time and energy. Microwave ovens are commonly used in homes, restaurants, and offices.

2. Satellite Communication
Microwaves are used to send signals between Earth stations and satellites in space. These signals help in television broadcasting, telephone communication, internet services, and GPS navigation. Microwaves are suitable for satellite communication because they can pass through the Earth’s atmosphere with very little loss.

3. Mobile Communication
Modern mobile phones use microwaves to communicate with nearby cell towers. Microwaves carry voice, text, and internet data at high speed. Because of their high frequency, microwaves allow many users to communicate at the same time without much interference.

4. Radar Systems
Microwaves are used in radar systems to detect objects such as aircraft, ships, and vehicles. Radar works by sending microwave signals and receiving the reflected waves from objects. This helps in air traffic control, military surveillance, weather forecasting, and speed detection by traffic police.

5. Wireless Internet (Wi-Fi)
Microwaves are used in Wi-Fi routers to provide high-speed internet connections. They allow wireless communication between routers and devices like laptops, smartphones, and tablets within a limited area. Microwaves make internet access fast and convenient without using cables.

6. Medical Applications
Microwaves are used in medical treatments such as cancer therapy, where controlled microwave energy is used to destroy cancer cells. They are also used in medical imaging and physiotherapy to heat body tissues and improve blood circulation.

7. Industrial Applications
In industries, microwaves are used for drying, heating, and curing materials such as rubber, wood, paper, and food products. Microwave heating is fast, uniform, and energy-efficient, which increases production speed and quality.

8. Navigation and Aviation
Microwaves are used in aircraft communication and navigation systems. They help pilots determine direction, altitude, and position. Airports use microwave-based radar systems to manage aircraft takeoff and landing safely.

Infrared Waves

Infrared waves are a type of electromagnetic radiation with wavelengths longer than visible light but shorter than microwaves. They are invisible to the human eye but can be felt as heat. Infrared waves cannot pass through walls, so they are mostly used for short-distance communication and sensing applications.

Infrared waves are widely used in remote controls, night vision devices, heat sensors, and wireless data transmission. They are safe for humans and are essential in modern electronics and everyday technology.

Advantages of Infrared Waves

1. Infrared waves are safe for humans because they are non-ionizing.
2. They can be used for short-distance wireless communication, such as in remote controls.
3. Infrared sensors can detect heat and motion, which is useful in security and automation.
4. They are widely used in medical treatments, such as physiotherapy and infrared lamps for healing.
5. Infrared waves are cheap and easy to use in many devices and systems.

Disadvantages of Infrared Waves

1. Infrared waves cannot pass through walls or solid objects, so they need a clear path.
2. Their range is limited, usually suitable for short distances only.
3. Infrared signals can be affected by sunlight or other strong light sources, which may cause interference.
4. Data transmission using infrared is slower compared to radio or microwaves.
5. They require line-of-sight communication, meaning the transmitter and receiver must face each other.

Applications of Infrared Waves

1. Remote Controls
Infrared waves are commonly used in TVs, air conditioners, and fan remote controls. The remote sends infrared signals to the device, which then performs the desired action, like changing channels or adjusting temperature.

2. Night Vision Devices
Infrared waves are used in night vision goggles and cameras to detect heat emitted by objects and living beings in the dark. This helps in security, military operations, and wildlife observation at night.

3. Thermal Imaging
Infrared waves are used in thermal cameras to detect heat patterns. They are used in firefighting, building inspections, medical diagnostics, and monitoring machinery for overheating.

4. Wireless Data Transmission
Infrared technology is used to transfer data between devices like laptops, smartphones, and printers. Although slower than Wi-Fi or Bluetooth, it is secure and suitable for short-range communication.

5. Medical Applications
Infrared waves are used in physiotherapy and infrared lamps for relieving pain, improving blood circulation, and healing injuries. They are also used in some diagnostic equipment to measure body temperature.

6. Industrial Applications
Infrared sensors are used in factories for motion detection, temperature monitoring, and automation. They help improve efficiency and safety in industrial processes.

7. Security Systems
Infrared sensors are used in security alarms, automatic doors, and intruder detection systems. They detect motion and heat changes to trigger alarms or open doors.

Comparison Between Hub and Repeater

Comparison Between Hub and Switch

Comparison Between Twisted Pair Cable and Optical Fiber

Comparison Between Coaxial Cable and Optical Fiber

Comparison Between UTP Cable and STP Cable

Comparison Between Guided Media and Unguided Media