Fundamentals_of_IT_2.pdf

Fundamentals of IT 2 JUDE KWAKU BONSU Teaching objectives By the end of this lecture you must be able to: Explain the term computer connectivity Explain the different ways in which connectivity can be classified, and the different options available Apply your knowledge of...

Fundamentals of IT 2 JUDE KWAKU BONSU Teaching objectives By the end of this lecture you must be able to: Explain the term computer connectivity Explain the different ways in which connectivity can be classified, and the different options available Apply your knowledge of computer connectivity to real life problems Computer connectivity Computer connectivity refers to the ability of devices or systems to connect and communicate with each other, sharing resources, data, or services. It enables the exchange of information, coordination, and collaboration between devices, networks, or systems. Computer connectivity can be classified based on their speed, purpose, connection method, protocols, topology, geographical scope Based on connection methods, computer connectivity can be classified as either wired or wireless Connection method (wired) Example of wired connections are ethernet cable, fiber optic cable and USB cable Among these, ethernet cables are the most ethernet common, and fiber optic cables the fastest fiber optic USB Connection method (wireless) Networks that use radio waves or other wireless technology to connect devices without physical cables Wireless networks often use access points (APs) to broadcast the wireless signal. These are devices that connect to the wired network and act as a bridge between wired and wireless devices. The receiving devices have wireless adapters such as Wi-fi cards or Bluetooth chips Example of wireless connection techniques are wireless fidelity (Wi-Fi), Light Fidelity (Li-Fi) Bluetooth Cellular networks, Long Term Evolution (LTE), LTE-advanced, 5G New radio, WiMax , meshed networks Connection method (wireless) Wi-Fi : connects devices to local area networks (LANs) and access the internet. Cellular networks (4G, 5G, LTE): enable mobile devices to make voice calls, send texts, and access data. Bluetooth: connects devices over short distances for file transfer, audio streaming, and device control Zigbee : a low-power, low-data-rate technology for home automation, IoT devices, and mesh networking WiMAX : a wireless broadband technology for metropolitan-area networks (MANs) LTE-Advanced (4G+): an enhanced version of LTE for mobile broadband 5G NR: the latest wireless network technology for ultra-high-speed mobile broadband Satellite internet: connects remote or underserved areas to the internet via satellite links. Mesh networks: a decentralized wireless network where each node acts as a repeater to extend coverage Li-Fi : uses light to transmit data between devices, often used in IoT applications. Connection method Feature Wired network Wireless Network Connection Method Physical cables (ethernet, fiber optic) Radio waves Reliability More reliable and stable Less reliable, prone to interference Speed Faster data transfer speeds Slower speeds compared to wired Mobility Limited mobility, requires cables More convenient, greater mobility Security More secure Less secure, requires proper security Connection speed Connectivity speed, often synonymous with network speed or data transfer rate, refers to the rate at which data is transmitted between two devices over a network. Mostly measured in bits per second (kbs, mbs, gbs, tbs). Network speed is characterized by bandwidth, latency, jitter and throughput. Bandwidth is the maximum rate at which data can be transmitted over a network connection. Higher bandwidth allows more data to be transmitted simultaneously, increasing overall speed. Connection speed continued…… Latency is the time it takes for a data packet to travel from the source to the destination. Lower latency results in faster communication and is crucial for real-time applications like video conferencing and online gaming. Jitter is the variation in latency and serves as a measure of the inconsistency in the time it takes for data packets to travel from source to destination Throughput is the actual rate at which data is successfully transferred over a network. It represents the effective data transfer rate, and is affected by bandwidth, latency, and other factors Low Speed (Less than 1 Mbps) Dial-up: Traditional phone line connections with speeds ranging from 56 kbps (kilobits per second) to a maximum of 384 kbps. Considered slow by today's standards but may still be found in remote areas. Basic DSL: Early versions of Digital Subscriber Line (DSL) technology offered download speeds up to 1.5 Mbps, but largely phased out by faster options. Medium Speed (1 Mbps to 100 Mbps) ADSL (Asymmetric DSL): A common DSL technology providing download speeds ranging from 1 Mbps to 25 Mbps, with slower upload speeds. Cable Internet: Cable broadband connections offered by cable TV providers typically deliver download speeds between 10 Mbps and 100 Mbps, with upload speeds being lower. High Speed (100 Mbps to 1 Gbps) Fiber Optic Internet: Utilizes fiber optic cables that transmit data using light pulses, enabling download speeds ranging from 100 Mbps to 1 Gbps (gigabit per second) and upload speeds approaching download speeds. Bonded DSL: Combines multiple DSL lines to achieve higher speeds, typically reaching up to 100 Mbps download speeds. Ultra High Speed (Above 1 Gbps) 10 Gigabit Ethernet (10GbE): Primarily used in enterprise and data center environments, offering download and upload speeds of 10 Gbps. Fiber Optic with Higher Speeds: Newer fiber optic technologies can theoretically reach speeds exceeding 10 Gbps, catering to the ever-growing demand for bandwidth. Connection speed Low-speed connections: Suitable for basic web browsing and email, but not recommended for streaming or downloading large files. Medium-speed connections: Good for basic internet activities like browsing, emailing, and streaming standard-definition videos. High-speed connections: Ideal for streaming HD videos, online gaming, and supporting multiple devices connected to the internet simultaneously. Ultra high-speed connections: Cater to high-bandwidth activities like 4K video streaming, large file transfers, and applications requiring low latency (minimal delay) for real-time communication. Factors that affect connection speed Network Infrastructure: Quality and capacity of routers, switches, and cables, Type of transmission media (e.g., fiber optic, copper wire, wireless). Internet Service Provider (ISP): Bandwidth provided by the ISP, ISP's network management practices and policies. Network Configuration: Settings and optimization of network devices, Network topology and architecture. Device Performance: Processing power and network interface of connected devices, Operating system and network drivers. Environmental Factors: Physical obstacles and distance in wireless networks, Electromagnetic interference from other devices. Connection Protocols Network protocols are essentially the set of rules and procedures that govern how data is communicated and exchanged between devices on a network. They act like a common language that allows different devices, regardless of their manufacturer or software, to understand each other and transmit information effectively. Network protocols are organized into layers, with each layer performing specific functions related to data communication. We will be using the OSI model to categorize the different levels of network protocols The layers include: Internet protocols , transport layer protocols, Network layer protocols, application layer protocol Network Layer Protocols This layer is responsible for routing data between devices on different networks. They consist of a number of protocols that operate at the network layer of the OSI model They include Internet protocols: responsible for addressing, routing and fragmentation Internet Control Message Protocol (ICMP): Used for error-reporting and diagnostic functions Internet Group Management Protocol (IGMP): Manages multicast group membership and routing: Routing Information Protocol (RIP): A distance-vector routing protocol for exchanging routing information. Network Layer Protocols Open Shortest Path First (OSPF): A link-state routing protocol for efficient routing and scalability. Border Gateway Protocol (BGP): Exchanges routing and reachability information among autonomous systems Intermediate System-Intermediate System (IS-IS): A link- state routing protocol for ISO networks Enhanced Interior Gateway Routing Protocol (EIGRP): A hybrid routing protocol for efficient routing and convergence Virtual Router Redundancy Protocol (VRRP): Provides redundant routing and failover capabilities. Dynamic Host Configuration Protocol (DHCP): Assigns IP addresses and other network settings to devices. Transport Layer Protocols Transport layer protocols ensures reliability, error correction and flow control They operate at the transport layer of the OSI model Examples are the Transmission Control Protocol (TCP), User Datagram Protocol (UDP), Stream Control Transmission Protocol (SCTP) These protocols differ in reliability, performance, efficiency, error detection etc. Application layer protocol An application layer protocol, residing at the topmost layer (layer 7) of the OSI model, acts as the interface between user applications and the network. This layer is responsible for providing services to end-user applications, such as email, file transfer, and web browsing. It includes Hypertext Transfer Protocol, File transfer protocol, Telnet More on application transfer protocols Hypertext Transfer Protocol (HTTP): Used for transferring web pages and data over the internet. Email protocols are the set of rules and standards that govern the transmission and reception of email messages over the internet. File Transfer Protocol (FTP): Used for transferring files over the internet. Telnet: Used for remote login and access to network devices. Domain Name System (DNS): Used for resolving domain names to IP addresses. Presentation layer protocol Presentation layer protocols reside in layer 6 of the OSI model Presentation layer protocols are responsible for ensuring data is presented in a format that both sending and receiving applications can understand. They handle data conversion, encryption, and compression tasks, essentially preparing the data for transmission across the network. They act as a bridge between the application layer and the network layer. Examples of presentation layer protocols are SSL, GIF, PNG…..etc Presentation layer protocol SSL (Secure Sockets Layer) and TLS (Transport Layer Security): These protocols provide data encryption and decryption services for secure communication GIF (Graphics Interchange Format): A protocol for compressing and transmitting graphics images JPEG (Joint Photographic Experts Group): A protocol for compressing and transmitting photographic images MPEG (Moving Picture Experts Group): A protocol for compressing and transmitting video images. ASCII (American Standard Code for Information Interchange): A character-encoding protocol for representing text characters. HTML (Hypertext Markup Language): A protocol for formatting and presenting web pages XML (Extensible Markup Language): A protocol for formatting and presenting data in a structured and organized way SSL/TLS certificates: Used for secure communication and authentication. PNG (Portable Network Graphics): A protocol for compressing and transmitting graphics images. TIFF (Tagged Image File Format): A protocol for compressing and transmitting graphics images.  Session layer protocols The session layer acts as a virtual meeting room coordinator for applications on different devices. It is responsible for managing and controlling the connections between computers. This includes establishing, maintaining, and terminating connections, as well as ensuring that data is properly synchronized and organized Three are debates about the existence of distinct session layer protocols Most of the protocols that execute “session layer-related” activities reside in other layers Some of these protocols include, AppleTalk Data Stream Protocol , Session Initiation Protocol etc.  Data link layer protocols The data link layer (DLL) is the second layer of the OSI model. It is responsible for transferring data between two devices on the same network The primary functions include, dividing data into frames for transmission, detecting and correcting errors, regulating the amount of data sent at a time, and managing access to the network medium The DLL can be divided into two sub-layers such as Medium Access Control (MAC) and Logical link control (LLC) sublayers Some key protocols within this layer are Ethernet, WI-FI, Point- to-Point Protocol (PPP), Asynchronous Transfer Mode (ATM), frame relay Connection Topology Connection topology refers to the arrangement or pattern in which network devices (such as computers, servers, and routers) are connected to each other. It defines the layout of the network, both physical and logical, and determines how data is transmitted between nodes. Physical Topology refers to the actual physical layout of the devices and cables in the network. It involves the placement of devices and how they are connected. Logical Topology refers to the way data flows within the network, regardless of its physical design. It describes the path that data takes from one device to another. Ring Topology In ring topology, each device is connected to two other devices, forming a circular data path The advantages of this topology include data is transferred quickly due to a simple data path and each device having an equal chance to transmit The main challenge is that failure of any device can disrupt the entire network, and it is difficult to troubleshoot and expand  Bus Topology In bus topology all devices are connected to a single central cable, known as the bus or backbone. It has the advantage of being easy to implement and extend and requires less cable than other topologies The main disadvantage is if the bus goes down, the entire network failed Star Topology In a star topology, all devices are connected to a central hub or switch. The hub acts as a repeater for data flow It has the advantages of easy to install, manage, trouble shoot and expand The main challenges to this type of network is a central hub failure can bring down the entire network, and it requires more cable than bus topology Mesh Topology In this network, every device is connected to every other device. Can be full mesh (every device connected to every other) or partial mesh (some devices connected). It has the advantage of high redundancy and reliability and a disadvantage of very high cost due to the large number of cables and ports, and complex installation and management. Hierarchical Topology This network is combination of star and bus topologies. Groups of star-configured networks are connected to a linear bus backbone. It has the advantage of being scalable and easy to manage. It has the disadvantage of a backbone failure affecting the entire network. Geographical networks Networks can be classified according to the size of the area which they cover Based on this network can be classified as Local Area Network, Wide Area Network, Metropolitan Network etc. In addition to the size of the area which they cover, the aforementioned networks also differ in terms of the demand in terms of connection method, and topology  Local Area Network Local Area Network (LAN) is a network that uses connection techniques such as WI-FI, ethernet cables to connect computers and devices in a limited geographic area, such as a home, office, or campus. They are usually involved in a high-speed and low latency data transfer. Due to the limited area in which they cover, and the fewer devices involved, LAN has low cost and high reliability Topology: Star, bus, ring. Media: Ethernet cables, Wi-Fi.  Wide Area Network A Wide Area Network (WAN) is a network that covers a broad area, connecting multiple LANs over large distances, such as cities, countries, or continents. The backbone of a WAN, typically consisting of high-speed telecommunication links like leased lines, fiber optic cables, or satellite connections provided by internet service providers (ISPs) or private network operators. Due to the wide area in which they cover, and the number devices involved, WAN has a high cost and redundancy is employed to improve reliability Topology: Mesh, hybrid. Media: Fiber optics, leased lines, satellite links. Metropolitan Area Network A Metropolitan Area Network (MAN) is network that spans a metropolitan area, typically larger than a LAN but smaller than a WAN network. A MAN connects multiple LANs within a city with moderate to high- speed data transfer using fiber optic cables or wireless connections Media: Fiber optics, wireless links. Campus Area Network A Campus Area Network (CAN) is network that covers a smaller geographic area , typically a university or corporate campus A MAN connects multiple LANs within the campus  Usage and purpose Classifying connectivity based on purpose refers to categorizing networks based on their intended use or the services they provide By doing this organization and individuals can choose their network based on their security needs, performance etc. Based on this criterion, networks can be classified as Storage Area Network, Enterprise Private Network, Virtual Private Network  Storage Area Network (SAN) A Storage Area Network (SAN) is a dedicated , high-speed network that connects storage devices and servers This network allow multiple servers to access shared storage resources A SAN provides block-level access to storage, enabling servers to treat the shared storage as if it were locally attached It can be used in cloud computing , database and media storage  Enterprise Private Network Enterprise Private Network (EPN) is a private, secure, and dedicated network that connects various locations and devices within an organization such as offices, branches, data centers etc. It is designed to provide a secure, reliable, and high-performance connectivity for the organization’s internal communication. Characteristics: High security, tailored to specific organizational needs. Depending on the area, EPN can be a WAN, LAN  VIRTUAL PRIVATE NETWORK Virtual Private Network (VPN) is a technology that creates a secure, encrypted connection over a less secure network, typically the internet. It allows users to send and receive data as if their devices were directly connected to a private network, providing privacy, security, and access to restricted resources. Masks the user’s IP address by replacing it with the IP address of the VPN server. Questions to consider What is/are the alternative(s) to the OSI How can network jitter be reduced Distinguish between intranet, internet and extranet Problem of the day 1 Genser Energy Ghana Limited is the biggest midstream gas distributer in Ghana. They supply natural gas from Takoradi to about 23 gas stations in Ghana over 5 regions. Their operations will require a gas significant communication between their various stations and their over 450 km pipeline. Propose a suitable network for them. Justify your choices between the type of connection medium, the geographical network, the type of topology, the speed of the network and purpose Problem of the day 2 You intend to send an email to your friend in Kenya. The email has word document and pictures attached. Discuss all the connectivity protocols that ensures that your friend receives the email safely and quickly.