Basic-Networking-Concepts.pdf

Basic Networking Concepts Network - A network is a group of systems that are connected to allow sharing of resources— such as files or printers—or sharing of services—such as an Internet connection. There are two aspects of setting up a network: the hardware used to connect the systems together an...

Basic Networking Concepts Network - A network is a group of systems that are connected to allow sharing of resources— such as files or printers—or sharing of services—such as an Internet connection. There are two aspects of setting up a network: the hardware used to connect the systems together and the software installed on the computers to allow them to communicate. The network hardware is made up of two basic components. Entities - The entities that want to share the information or resources, such as servers and workstations, Medium - The medium that enables the entities to communicate, which is a cable or a wireless medium. Servers, Workstations, and Hosts Servers - The server is a special computer that contains more disk space and memory than are found on client workstations. The server has special software installed that allows it to function as a server. This special software can provide file and print services (to allow sharing of files and printers), provide web pages to clients, or provide e-mail functionality to the company. Workstations - A typical network involves having users sit at workstations, running such applications as word processors or spreadsheet programs. The workstation also is known as a client, which is just a basic computer running a client operating system such as Windows XP or Linux. These users typically store their files on a central server so that they can share the files with other users on the network. Hosts - The term host refers to any computer or device that is connected to a network and sends or receives information on that network. A host can be a server, a workstation, a printer with its own network card, or a device such as a router. We can summarize by saying that any system or device that is connected to the network is known as a host. WANs, LANs, and MANs LOCAL AREA NETWORK (LAN) - Connects computers and devices within a limited area, such as a building or campus. Typically used for sharing resources and files. Examples: Home networks, office networks. METROPOLITAN AREA NETWORK (MAN) - Connects computers and devices within a metropolitan area. Not as used. Larger than a LAN but smaller than a WAN. Examples: City- wide networks, university networks. WIDE AREA NETWORK (WAN) - Connects computers and devices across a large geographic area. Often used to connect cities, states, or countries. Examples: The internet, long-distance phone networks. Types of Networks Peer-to-Peer Network - In peer-to-peer networks, every computer acts as both a client and a server, allowing for direct communication without a central authority. This decentralized  structure makes P2P networks ideal for file sharing, decentralized applications like Bitcoin, and online gaming. Examples of P2P networks include BitTorrent and Gnutella. Server-based Network - Server-based networks have a centralized architecture with one or more servers that provide resources and services to connected clients. This centralized approach offers benefits such as easier management, enhanced security, and improved scalability. Server-based networks are commonly found in corporate environments, web hosting, and email services. Examples include traditional client-server architecture and cloud computing platforms. Server Services - The server in a server-based network may provide a number of different services. The services it will offer to the network usually are decided by the server’s role. There are a number of different roles that a server could play on a network. File and Print Servers - File and print servers are essential components of server-based networks, responsible for managing the sharing of files and printers among network users. These servers typically feature high-performance hardware, such as large amounts of memory, fast hard drives, multiple CPUs, and redundant power supplies, to ensure efficient and reliable operation. Additionally, file and print servers often implement access control lists (ACLs) to regulate access to shared resources, preventing unauthorized use and maintaining data security. Application Servers - Application servers are specialized servers that run specific software applications, providing various services to network users. These applications can range from email servers and database servers to custom-built business applications. Application servers often require powerful hardware to handle the computational demands of the software they run, and they may also need to be configured with specific software settings or integrations to meet the needs of the network. Web Servers - Web servers are designed to deliver web content to clients over the internet or a local intranet. They process requests from clients, retrieve the requested content from web pages or databases, and send the content back to the client's web browser. Web servers play a crucial role in enabling online services and applications, such as websites, e- commerce platforms, and content management systems. They often require high performance network interfaces and efficient web server software to handle large volumes of traffic and provide fast response times. Directory Servers - Directory servers act as central repositories for user accounts and other network-related information. They store data about users, groups, computers, and other network objects, allowing for efficient management and administration. Directory servers are essential for implementing authentication, authorization, and access control mechanisms within a network. They provide a centralized location for managing user accounts, assigning permissions, and enforcing security policies. Internet, Intranet, and Extranet Internet - The internet is a vast, interconnected network of computers and devices worldwide, accessible to anyone with an internet connection. It serves as a global platform for communication, information sharing, and access to countless resources. The internet uses a standardized set of protocols, such as HTTP, FTP, and SMTP, to facilitate data transmission and interaction between different devices and networks.  Intranet - An intranet is a private network within an organization, accessible only to authorized users. It provides a secure and controlled environment for internal communication, collaboration, and information sharing. Intranets often utilize internet protocols but are restricted to the organization's internal network, ensuring data confidentiality and security. Common intranet applications include employee directories, company news, document sharing platforms, and internal databases. Extranet - An extranet is an extension of an intranet that allows controlled access to selected external users, such as business partners, suppliers, or customers. It provides a secure and efficient way to share information and collaborate with external parties. Extranets are typically used for tasks like customer self-service, partner portals, and supply chain management. While extranets are accessible to external users, they are still subject to the organization's security policies and access controls. Identifying Network Topologies Bus Topology - Bus topology is a network configuration where all devices are connected to a single central cable, known as the bus or backbone. This setup allows data to be transmitted in one direction along the bus, with each device receiving the data until it reaches its destination. Star Topology - Star topology is a network configuration where each device is connected to a central hub or switch. The central hub acts as a server, and the connected devices act as clients. Data is transmitted from the central hub to the intended device. Mesh Topology - Mesh topology is a network configuration where each device is interconnected with every other device. This setup provides multiple paths for data to travel, ensuring high redundancy and fault tolerance. Ring Topology - Ring topology is a network configuration where each device is connected to two other devices, forming a circular data path. Data travels in one direction (unidirectional) or both directions (bidirectional) around the ring. Hybrid Topology - Hybrid topology is a network configuration that combines two or more different topologies, such as star, bus, ring, and mesh, to leverage their strengths and minimize their weaknesses. Wireless Topology - Wireless topology is a network configuration where devices are connected without physical cables, using wireless communication technologies such as Wi-Fi, Bluetooth, or cellular networks. Network Media and Connectors Network Media - The medium through which information is transferred. Wireless Media – Copper cabling and Fiber Optic cables. Wireless Media. Copper Cable - Copper cabling, the most traditional and widely used medium, transmits electrical signals across copper conductors. Unshielded Twisted Pair (UTP) - The most common cable in Ethernet networks. UTP is affordable and easy to install but is susceptible to electromagnetic interference (EMI). Shielded Twisted Pair (STP) - Contains additional shielding to reduce EMI and crosstalk. It is more expensive and bulkier than UTP. Twisted Pair Cable Applications - Used in local area networks (LANs), particularly in Ethernet networks. Connector - RJ45 and RJ11 connectors are commonly used with twisted pair cables. Coaxial Cable - Consists of a central conductor, insulating layer, metallic shield, and outer cover. It is more resistant to EMI than UTP. It can be used for both analog and digital transmission. Applications - Used in cable television and older Ethernet standards Connector - BNC (Bayonet Neill-Concelman) are used for coaxial cables. USB Cable - A type of wired communication medium that uses the Universal Serial Bus (USB) standard to connect and transfer data and power between devices. Application - It is widely used to connect computers, smartphones, peripherals (like printers, keyboards, and external hard drives), and other electronic devices. Fiber Optic Cable - Fiber optic cables transmit data as light signals rather than electrical signals. They offer much faster data transfer rates and are immune to EMI. Applications - Used in high-speed networks, including backbone cabling, wide area networks (WANs), and telecommunications. Connector - SC, ST, and LC connectors are commonly used with fiber optic cables. Single-mode Fiber - Designed for long-distance communication, it uses a small core and single light mode, allowing signals to travel over long distances without much attenuation. Multi-mode Fiber - Features a larger core and allows multiple light modes, suitable for shorter distances. Fiber Option Connector Types Lucent Connector, Standard Connter, ST Connector Wireless Media - Wireless media use radio waves, infrared, or microwaves to transmit data without physical cabling. Wireless media include Wi-Fi, Bluetooth, and cellular networks. Wi-Fi (Wireless Fidelity): The most common wireless media for local area networks, providing flexibility and mobility. Applications - Used in homes, offices, and public spaces for mobile connectivity. Connector - Antennas and access points are used to connect wireless devices to a wired network. Access Methods - Access methods are the rules and protocols that determine how devices on a network use to share the communication medium (such as a cable or a wireless frequency) and to transmit data without conflicts or collisions occurring. An access method is designed to guarantee that several devices can interact with a shared medium by transmitting data without complex interferences and ensuring the reliable transmission of information. Common Access Methods Carrier Sense Multiple Access with Collision Detection (CSMA/CD) - Used in Ethernet networks, it allows devices to detect collisions and retransmit data. Common in: Ethernet (Wired Networks) although collision detection is less common in modern switched networks, this method laid the foundation for early LAN communication. Carrier Sense Multiple Access with Collision Avoidance (CSMA/CA) - Used in wireless networks, it tries to avoid collisions by waiting for a clear channel before transmitting. Common in: Wi-Fi (Wireless Networks) Essential for wireless communication where detecting collisions can be difficult. Token Passing - On a local area network, token passing is a channel access method where a packet called a token is passed between nodes to authorize that node to communicate. Common in: Older LAN Technologies, Legacy technologies like Token Ring networks and FDDI (Fiber Distributed Data Interface). While not as common today, it was used in older LANs for collision-free data transmission. Time Division Multiple Access (TDMA) - is a digital modulation technique used in digital cellular telephone and mobile radio communication. TDMA is one of two ways to divide the limited spectrum available over a radio frequency (RF) cellular channel. Common in: Cellular networks, satellite communications, Used in 2G (GSM) cellular networks and satellite communications. Frequency Division Multiple Access (FDMA) - is a channel access technique found in multiple access protocols as a channelization protocol. It permits individual allocation of single or multiple frequency bands, or channels to the users. FDMA, just like any other multiple access system, harmonizes access between multiple users. Common in: Radio and television broadcasting, early cellular networks, Used in analog cellular systems (1G), radio and TV broadcasting, and satellite communication. Code Division Multiple Access (CDMA) - is a technique that allows multiple users to simultaneously transmit data signals over a common channel by assigning unique spreading code to each individual user. Common in: 3G Mobile Networks, satellite communication and GPS systems. Orthogonal Frequency Division Multiple Access (OFDMA) - a technology in Wi-Fi 6, improves wireless network performance by establishing independently modulating subcarriers within frequencies. This approach allows simultaneous transmissions to and from multiple clients. Common in: Wi-Fi 6 (802.11ax), 4G LTE, and 5G Networks, Modern Wi-Fi and 4G/5G mobile networks for high data efficiency and low latency. Network Architectures What is Network Architecture? - Network architecture defines the structured interaction between network services, devices, and clients to meet their connectivity requirements. Network devices typically include switches and routers. Types of services include DHCP and DNS. Client devices comprise end-user devices, servers, and smart things Benefits and Challenges of Different Network Architectures Different network architectures cater to various needs based on their scale and reach, and each presents unique advantages and limitations. For example, Local Area Networks (LANs) - provide high-speed connectivity and efficient data transfer within limited geographical areas, like offices or homes. Conversely, Wide Area Networks (WANs) - offer broad coverage spanning cities or countries but at the cost of slower data transfer rates due to the large distances involved. Four Components of Network Architecture Design Servers - A server is a powerful computer or system that provides resources, services, or data to other devices (called clients) in a network. Servers can host websites, manage email, store files, run applications, or serve as databases. Common types include web servers, file servers, and database servers. Routers - Routers act as the postmasters of the network, directing data traffic. They connect networks and shuttle data packets between them based on the data’s destination IP address. A router subdivides the network into two or more smaller networks that are connected by it, and it won’t allow the broadcast to flow between subnets. Firewalls - Firewalls are the security guards of the network, protecting the network from unauthorized access and malicious attacks. Firewalls examine incoming and outgoing network traffic based on predefined security rules, allowing authorized traffic while blocking unauthorized or malicious activity. Switches - Switches are network traffic controllers that channel data to the correct device within a network. Unlike routers, switches operate within a single network. It provides a central place of connections for all the different devices on the network. Common Types of Network Architecture  Peer -to-peer architecture: In a peer-to-peer network, all devices, often called “peers,” have equal capabilities and responsibilities. This architecture doesn’t require a central server, and all devices communicate directly with each other. The distribution of resources in P2P networks makes them potentially more resilient to failure than centralized architectures, as the failure of one node doesn’t significantly impact the entire network. Client-Server: In a client-server architecture, some computers (servers) provide services, and other computers (clients) use those services. The server has more processing power and storage and performs most of the work. This centralization can make network maintenance easier but also presents a single point of failure. Hybrid: Hybrid networks combine elements of the client server and peer-to-peer architectures. Some devices in the network act as clients and access services, while others act as servers and provide services. Some devices fulfill both roles. Cloud-Based Architecture: Cloud-based networks offer services and storage over the internet. Users don’t need to maintain their hardware and software; instead, they can access applications and storage provided by cloud service providers. This flexibility allows for easy scaling and global accessibility. Software-Defined Networking (SDN): In an SDN architecture, the network’s control and forwarding functions are decoupled. This separation allows for centralized management and control over the entire network, promoting flexibility and rapid deployment of new services. Types of Networks Based on Coverage Area Local Area Network (LAN): A LAN connects devices within a limited area like a home or office. It is efficient and offers high-speed connectivity. Wide Area Network (WAN): WANs connect devices over larger geographical areas, such as between cities or countries. They are often slower than LANs due to the vast distance data has to travel. Metropolitan Area Network (MAN): MANs connect users within a city. They’re larger than LANs but smaller than WANs. Personal Area Network (PAN): PANs connect devices within an individual’s workspace or personal range. The Internet (A Network of Networks): The internet is a global network of computer networks connected via TCP/IP protocols. Network Protocols - Network protocols are sets of rules that govern how devices on a network communicate. They define how data is formatted, addressed, transmitted, and received. Some key network protocols include: Internet Protocol (IP): IP manages the addressing and routing of data packets, enabling them to move through different networks and arrive at the correct destination. Transmission Control Protocol (TCP): TCP ensures reliable data transmission by breaking data into packets, sending them, and reassembling them correctly at the destination.  User Datagram Protocol (UDP): Unlike TCP, UDP prioritizes speed over reliability, sending packets without ensuring their delivery. It's commonly used for applications like live streaming and gaming, where speed is more critical than accuracy. Transmission Media - Transmission media refers to the physical or virtual paths by which data travels from one point to another in a network. There are two primary types of transmission media: Wired Networks - Wired networks use physical cables, typically Ethernet, to connect devices. These networks offer faster data transfer speeds and enhanced security, as they are less prone to interference and unauthorized access. However, their flexibility is limited by the physical layout of the cables, and installation can be labor-intensive and costly, especially in larger or more complex setups. Wireless Networks - Wireless networks transmit data via radio waves, with Wi-Fi and cellular protocols like 4G and 5G being the most common. They offer great flexibility, allowing devices to connect from any location within range, and are easier to install since no physical cables are required. However, wireless connections typically have slower data transfer rates compared to wired networks and are more susceptible to interference and security risks. Strong security protocols, such as WPA3, are essential for safeguarding wireless networks. Network Operating Systems Network Operating System - A network operating system (NOS) is software that connects multiple devices and computers on the network and allows them to share resources on the network. Functions of the NOS (Network Operating System) The following are the main functions of NOS: Creating and managing user accounts on the network. Controlling access to resources on the network. Provide communication services between the devices on the network. Monitor and troubleshoot the network. Configuring and Managing the resources on the network. Types of Network Operating System Peer to Peer: Peer-to-peer network operating systems allow the sharing of resources and files with small-sized networks and having fewer resources. In general, peer-to-peer network operating systems are used on LAN. Client/server: Client-server network operating systems provide users access to resources through the central server. This NOS is too expensive to implement and maintain. This operating system is good for the big networks which provide many services. Features of Network Operating System Printers and application sharing on the network.  File systems and database sharing. Provide good security by using functionality like user authentication and access control. Create backups of data. Inter-networking. Advantages and Disadvantages Highly stable due to central server. Provide good security. Upgradation of new technology and hardware can be easily implemented in the network. Provide remote access to servers from different locations. Depend on the central location to perform the operations. High cost to buying server. Regular updating and maintenance are required. Network Operating Systems Microsoft Windows Server Unix / Linux Artisoft’s Lantastic