Introduction to Networking - 1.pdf

INTRODUCTION TO NETWORKING 1. Networking is the practice of connecting computers and other devices to share resources, such as data, applications, and hardware (e.g., printers, scanners).  Key Concepts: o Nodes: Devices connected to a network, such as comp...

INTRODUCTION TO NETWORKING 1. Networking is the practice of connecting computers and other devices to share resources, such as data, applications, and hardware (e.g., printers, scanners).  Key Concepts: o Nodes: Devices connected to a network, such as computers, printers, and servers. o Links: Physical or wireless connections between nodes that facilitate data transmission. o Data: Information that is exchanged between devices, which can be in the form of text, images, videos, etc. 2. Purpose and Benefits of Networking Purpose: Networking's primary purpose is to enable the sharing of resources and information among devices. Benefits:  Resource Sharing: Networks allow multiple users to access shared resources, such as printers, files, and applications, without needing individual copies for each device.  Communication: Networking enables various forms of communication, such as emails, instant messaging, voice calls, and video conferencing.  Data Management: Centralized data storage in networks makes it easier to manage, back up, and secure data.  Scalability: Networks can easily grow by adding new devices, allowing businesses to expand. Example: Adding new workstations to a company’s network.  Cost Efficiency: Networking reduces costs by allowing shared resources 3. Open Systems Interconnection (OSI) Model is a conceptual framework that standardizes the functions of a telecommunication or computing system into seven distinct layers.  Layer 1: Physical Layer - Deals with the physical connection between devices Example: Ethernet cables and fiber optics operate at this layer.  Layer 2: Data Link Layer - Manages the node-to-node data transfer and error detection and correction. Example: MAC addresses and Ethernet operate at this layer.  Layer 3: Network Layer - Handles the routing of data packets between devices across different networks. Example: IP addresses and routers operate at this layer.  Layer 4: Transport Layer - Ensures complete data transfer with error checking, flow control, and data retransmission if necessary. Example: TCP and UDP operate at this layer.  Layer 5: Session Layer - Manages sessions or connections between applications. Example: Network file sharing protocols and remote desktop access operate at this layer.   Layer 6: Presentation Layer - Translates data between the application layer and the lower layers. Example: SSL encryption and data compression operate at this layer.  Layer 7: Application Layer - The closest layer to the end-user, responsible for providing network services directly to the applications. Example: Web browsers (HTTP), email clients (SMTP), and file transfer protocols (FTP) operate at this layer. 4. TCP/IP Model Overview Transmission Control Protocol/Internet Protocol (TCP/IP) Model is a simplified four-layer framework that is used as the foundation for the internet and most modern networks.  Layer 1: Network Interface Layer - Combines the physical and data link layers of the OSI model. Example: Ethernet and Wi-Fi operate at this layer.  Layer 2: Internet Layer - Corresponds to the network layer in the OSI model. Example: IP and ICMP operate at this layer.  Layer 3: Transport Layer - Similar to the OSI transport layer, it handles end- to-end communication, ensuring data integrity and proper sequencing. Example: TCP and UDP operate at this layer.  Layer 4: Application Layer - Combines the OSI application, presentation, and session layers. It provides services directly to applications, supporting protocols like HTTP, FTP, SMTP, and DNS. Example: Web browsing, email, and file transfer operate at this layer. NETWORK TOPOLOGIES 5. Network Topologies Network Topology refers to the physical or logical arrangement of network devices and how they are connected to each other.  Bus Topology: All devices share a single communication line or cable. o Advantages: Easy to implement and cost-effective for small networks. o Disadvantages: A failure in the main cable can bring down the entire network. o Example: Early Ethernet networks.  Star Topology: All devices are connected to a central hub, switch, or router. o Advantages: Easy to manage and expand; a failure in one cable does not affect the entire network. o Disadvantages: If the central device fails, the entire network goes down. o Example: Most modern home and office networks.  Ring Topology: Each device is connected to two other devices, forming a circular pathway for data to travel. o Advantages: Data is transmitted in one direction, reducing the chance of packet collisions.  o Disadvantages: A failure in any device or connection can disrupt the entire network. o Example: Some early local area networks (LANs) and metropolitan area networks (MANs).  Mesh Topology: Devices are interconnected, with each node connected to many others. This provides multiple paths for data to travel between any two points. o Advantages: High redundancy and reliability; if one path fails, data can take another route. o Disadvantages: Expensive and complex to implement due to the high number of connections. o Example: Some WANs and large-scale wireless networks.  Hybrid Topology: Combines two or more different types of topologies to form a more complex network. o Advantages: Flexibility and scalability; can be tailored to specific needs. o Disadvantages: Can be complex and expensive to implement. o Example: Large enterprise networks often use a combination of star, mesh, and bus topologies. 6. Types of Networks Networks can be categorized based on their geographic scope and the type of technology used.  Local Area Network (LAN):Covers a small geographic area, such as a single building or campus. Example: A school network connecting classrooms and administrative offices.  Wide Area Network (WAN): Spans a large geographic area, often connecting multiple LAN’s. Example: The internet is the largest WAN, connecting networks around the world.  Metropolitan Area Network (MAN): Covers a larger area than a LAN but smaller than a WAN, such as a city or a large campus. Example: A city government network that connects various municipal buildings.  Personal Area Network (PAN):A small network designed for individual use, typically within a range of a few meters. Example: A Bluetooth connection between a smartphone and a wireless headset.  Virtual Private Network (VPN): Extends a private network across a public network, allowing users to send and receive data as if their devices were directly connected to the private network. VPNs provide secure communication over the internet. Example: Remote workers using a VPN to securely access their company's network from home. 7. Type of Data Transmission Data is transmitted to and from host on networks using one of three transmission type.  Unicast traffic: is traffic sent from one computer to one other computer. Unicast: one to one.  Broadcast traffic: by one computer and goes to all computers within a subnet. Broadcast: one to all.  Multicast traffic: from one computer to many other computers. Multicast: one to many. 8. Collision Domain is a group of devices on the same segment that are subject to collisions. Collision occur when two devices on the same segment send traffic at the same time. 9. Broadcast Domain is a group of devices on a network that can receive broadcast traffic from each other. 10. Transmission Modes it defines the direction of the flow of information between two communication devices. Three types of Transmission Mode:  Simplex Mode: data can flow in only one direction means data communication is unidirectional. Sender can only send data but can’t receive it similarly. Receiver only receive data but can’t send it.  Half-Duplex Mode: data can flow in both directions but in one direction at a time. One device is sending the other can only receive and vice versa.  Full-Duplex Mode: data can be transmitted in both directions simultaneously. Two devices can send and receive data at the same time without any delay or waiting time. 11. NIC(Network Interface Card) network adapter that is used to connect the computer to the network. NIC card is a layer 2 device which means work on both the physical and data link layer of the network model. Types of NIC INTERNAL NIC  Wired NIC: cables and connectors use Wired NIC to transfer data.  Wireless NIC: these connect to a wireless network such as Wifi, Bluetooth, etc. EXTERNAL NIC  USB NIC 12. MAC Address is a physical address that is assigned by the manufacturer on a network interface card(NIC), use to uniquely identify a device on a network. 13. HUB is a basically multi-port repeater. A hub connects multiple wires coming from different branches, for example, the connector in star topology which connects different stations. HUB in Networking is a basic networking device that is used to connect multiple devices together on a local network. How HUB works? like a electric wire, it receives data signal from one device in one port and forward them to all the other ports, except the source port. The basic process of a hub device:  Data transmission: when a device wants to send data to another device on the network, it send the data to the hub.  Broadcasting: the data to all to other connected devices by transmitting the data out on all of its ports.  Data reception: the receiving device receives the data from the hub and processes it.  Data collision: if two devices send data to the hub at the same time, their data will collide and neither device will be able to receive the data. 14. SWITCH is a multiport bridge with a buffer and a design that can boost its efficiency and performance. A switch is a data link layer device. SWITCH in Networking is a network device that has multiple ports, used to connect computer devices and create a network. Advantages of SWITCH Device  Multiple computers can connect using the switch and communicate with each other.  Switch is able to work on full-duplex mode 15. ROUTER is a device like a switch that routes data packets based on their IP addresses. A router is mainly a Network Layer device. ROUTER in Networking is a networking device that connects multiple networks together and directs traffic between them. Basic Features of ROUTER in Networking  it allows connecting two or more LAN networks.  to connect to the internet because the internet is a group of networks.  it comes in 2, 4, or 8 ports.  it stores destination IP addresses in its routing table. 16. MODEM is a short form of Modulator/Demodulator. Modem is a hardware component/device which can connect computers and other devices such as routers and switches to the internet.