ICT Notes Networking Devices PDF

Some hardware devices used in computer networking include Router: A router is a networking device that connects multiple networks and directs data packets between them. It determines the best path for forwarding the data to its destination, allowing devices on different networks to communicate. In...

Some hardware devices used in computer networking include Router: A router is a networking device that connects multiple networks and directs data packets between them. It determines the best path for forwarding the data to its destination, allowing devices on different networks to communicate. In simpler terms, a router acts like a traffic director for your network, ensuring data (e.g., emails, web pages, files) is sent to the correct destination efficiently. Let us understand this by a very general example, suppose you search for www.google.com in your web browser then this will be a request that will be sent from your system to Google`s server to serve that webpage, now your request which is nothing but a stream of packets don`t just go to the google`s server straightaway they go through a series of networking devices known as a router which accepts this packets and forwards them to correct path and hence it reaches to the destination server. A router has several interfaces by which it can connect to several host systems. Routers are the devices that are operated on the Network Layer of the OSI Model, these are the most common devices used in networking. An office has two departments: HR and IT. Each has its own network, and the office uses a router to connect them to each other and the internet.  How it works: Employee in HR needs to send a file to IT: The HR computer sends the file to the router, which checks its routing table. The router sees that the IT network is within the internal LAN and sends the file to the IT computer. Employee in IT wants to access cloud software: The IT computer sends a request to the router for the cloud service. The router forwards the request to the internet through the ISP (Internet Service Provider). The cloud software sends a response back to the router, which directs it to the IT computer. HUB 1 Hub in networking plays a vital role in data transmission and broadcasting. A hub is a hardware device used at the physical layer to connect multiple devices in the network. Hubs are widely used to connect LANs. A hub has multiple ports. Unlike a switch, a hub cannot filter the data, i.e. it cannot identify the destination of the packet, So it broadcasts or sends the message to each port.  Hubs are often used in a star topology, where devices are connected to the hub in a central arrangement. The hub itself is the central node, and all data flows through it.  Hubs operate in half-duplex mode, meaning data can only flow in one direction at a time. Feature Hub Switch Router OSI Layer Physical (Layer Data Link Network (Layer 1) (Layer 2) 3) Data Filtering None By MAC By IP Address Address Traffic Broadcasts to Directs to Routes between Management all specific networks Efficiency Low High Very High Cost Low Moderate High Duplex Mode Half-Duplex Full-Duplex Full Duplex Switch: A switch in networking is a device that connects multiple devices on a local area network (LAN) and enables communication between them. It operates at 2 Layer 2 (Data Link Layer) of the OSI model, though some switches also work at Layer 3 (Network Layer). A switch maintains a table of Media Access Control (MAC) addresses associated with its ports. When a device connects, the switch learns its MAC address and maps it to the port it’s connected to. When a data packet arrives, the switch checks the destination MAC address. If it knows which port the destination device is on, it forwards the packet only to that port. If not, it broadcasts the packet to all ports. Switches support simultaneous sending and receiving of data, reducing collisions compared to older hubs. Advantages Increased Network Efficiency: Sends data only where it's needed. Reduced Collisions: Full-duplex communication eliminates data collision issues common in hubs. Scalability: Can expand networks with multiple switches. Disadvantages Cost: Managed switches, Layer 3 switches, or those with advanced features (like VLANs or PoE) can be expensive compared to simpler networking devices like hubs. Limited Distance: Ethernet cables used with switches typically have a maximum effective range of 100 meters. For larger networks, additional devices like repeaters or fiber connections are needed. Single Point of Failure: In centralized network setups, if the main switch fails, connected devices lose communication. Scalability Concerns: Adding multiple switches to a network may require careful planning to avoid creating loops or exceeding device and port limits. 3 Bridge: The bridge is a networking device in a computer network that is used to connect multiple LANs to a larger LAN. In computer networks, we have multiple networking devices such as bridges, hubs, routers, switches, etc, each device has its own specification and is used for a particular purpose. The bridge is a networking device that connects the larger LAN networks with the group of smaller LAN networks. A bridge in a computer network is a device used to connect multiple LANs together with a larger Local Area Network (LAN). The mechanism of network aggregation is known as bridging. The bridge is a physical or hardware device but operates at the OSI model’s data link layer and is also known as a layer of two switches. Advantages  Bridges can be used as a network extension like they can connect two network topologies together.  It has a separate collision domain, which results in increased bandwidth.  It can create a buffer when different MAC protocols are there for different segments.  Highly reliable and maintainable. The network can be divided into multiple LAN segments. Disadvantages  Expensive as compared to hubs and repeaters.  Slow in speed.  Poor performance as additional processing is required to view the MAC address of the device on the network.  As the traffic received is in bulk or is broadcasted traffic, individual filtering of data is not possible. 4  During the broadcasting of data, the network has high broadcast traffic and broadcast storms can be formed. Gateway A gateway is a network connectivity device that connects two different configuration networks. Gateways are also known as protocol converters, because they play an important role in converting protocols supported by traffic on different networks. As a result, it allows smooth communication between two networks. 1. Gateways provide security within the network. 2. A gateway is situated at a network edge and manages all data that enters or exits the network.  The gateway receives data from devices within the network.  After receiving data the gateway intercept and analyse data packets, which include analyzing packet header, payload etc.  Based on the analysis of the data packets, the gateway calculates an appropriate destination address of data packet. It then routes the data packets to their destination address. Difference between router and gateway:  A gateway enables communication between different types of networks by translating protocols.  A router connects and routes data between similar networks, focusing on forwarding packets based on IP addresses. Amplifier: In networking, an amplifier is a device that boosts the strength of an electrical or optical signal to extend the range of data transmission. Amplifiers are 5 primarily used in analog communication systems, such as radio, television broadcasting, and fiber optic networks. 1. Transmission Distance: Extends the reach of communication systems by boosting the signal power over long cables or transmission mediums. 2. Signal Strengthening: Amplifies the power of a weak signal to ensure it can travel longer distances without significant degradation. Repeater: A repeater takes a signal and sends it on with more power. It’s like a relay runner passing a baton. The repeater has an amplifier inside it to make the signal stronger. Different types of signals need different repeaters. For example, light signals need special light-sensing parts. Repeaters are very important for digital communication. They work at the basic level of sending signals.  Repeater can regenerate the signal without modifying it.  Repeaters can be used in analog signals and digital signals.  Repeaters can extend the range of networks. Difference between Repeater and Amplifier Repeater Amplifier 6  Repeater Amplifier The Repeaters regenerates the signal if Amplifier increases the amplitude the provided original signal is so weak. of the signal. Repeater takes high input power and Amplifier takes low input power provides low output power. and provides high output power. Repeater is generally used in Amplifier is generally used in static(stationary) environment. Mobile and Remote area network. Repeater regenerates the signal so that Amplifier increases the amplitude the noise can be reduced or eliminated. of the signal with the noise. Repeater works on the physical layer of Generally Amplifier is used in OSI model. wireless communication. 7