Computer Networking Concepts PDF

IT2221 THE VAST NETWORK Network Architecture Key Concepts of Computer Networking It is a diagram displaying the structure of network devices and services...

IT2221 THE VAST NETWORK Network Architecture Key Concepts of Computer Networking It is a diagram displaying the structure of network devices and services to serve the clients' connectivity needs. Computer Networking links computers for shared resources through the internet. Networking requires computers to access multiple networks and share their resources for computer operations, including web browsing, sending and retrieving emails, sharing files and images, and downloading music. Organizations such as companies, schools, and government agencies enforce the use of single-user or general-purpose computer networks for word processing, scientific computation, and control processing. Network Categories based on Geography Networks are categorized based on their geographic scope: Source: https://www.cisco.com/c/en/us/solutions/enterprise-networks/what- Personal Area Network (PAN): The smallest type of network with is-network-architecture.html a limited span interconnects compatible personal devices. Figure 1. A sample network architecture Examples include wireless earphones-to-smartphone and computer-to-printer connections. Common Types of Network Architecture Local Area Network (LAN): This is used to interconnect and Fulfilling the needs of the client is the biggest goal of computer share computer resources in an establishment such as a networks. Here are the three common types of enterprise networks: corporate building, house, or several buildings in a limited area. 1. Access networks in campuses and branches bring users Campus Area Network (CAN): An enterprise network covering and devices together, such as linking employees in a multiple buildings in a campus environment, including universities corporate building. and large organizations. 2. Networks for data centers in a company link multiple servers Metropolitan Area Network (MAN): This covers multiple city with data and applications and make them easily accessible buildings, traffic lights, and parking meters, connecting wirelessly to users. as a metropolitan area network. 3. Wide-area networks (WANs) connect users to programs and Wide Area Network (WAN): A much larger network covering vast services, such as hospital employees connecting to health areas, such as cities, provinces, and countries. WAN can also be applications. a bigger network consisting of LANs and MANs. 05 Handout 1 *Property of STI  [email protected] Page 1 of 4  IT2221 The Open Systems Interconnection Model The Layers of the OSI Model The Open Systems Interconnection (OSI) reference model of the 1. Physical layer – gives electrical and mechanical connections to International Organization for Standardization was developed in 1984 the network. as an open standard for every communication system to allow the interlinking of different types of networks. 2. Data link layer – handles error recovery, flow control, and sequencing of terminals that are either sending or receiving. It is Application the media access control (MAC) layer where MAC addressing is defined. Presentation 3. Network layer – acts as the network controller that receives outgoing messages and combines messages and segments into Session packets with a header detailing the routing information. 4. Transport layer – liable for end-to-end delivery between devices. Transport It deals with message integrity between source and destination and segmenting and reassembling packets. Network 5. Session layer – provides the control functions required to start, manage, and end connections to satisfy user requests. Data Link 6. Presentation layer – accepts and structures the messages for an application by converting the message from one code to another. Physical It also processes data compression and encryption. 7. Application layer: It interacts with application programs with Source: Beasly J., Nilkaew P. (2022). Networking essentials: Sixth edition. Pearson. communication components such as a web browser and email. It Figure 1. The seven layers of the OSI model is responsible for recording a message, understanding the request, and identifying the information needed to support it. The OSI reference model has seven layers describing networking functions, from the physical network interface to the software application interface. OSI model aims to provide a structure for networking that secures compatibility in the network hardware and software and expedites the advancement of upcoming networking technologies. 05 Handout 1 *Property of STI  [email protected] Page 2 of 4  IT2221 Summary of the OSI Layers Layer Function Wired Network Devices Physical Handles signal and media 1. LAN Ethernet Cable – connects devices within a local area Data Link Assigned for the flow of data network. It is limited by length and durability specifications resulting in a bad signal if the cable is too long or of poor quality. Network Provides addressing and routing decisions Manages end-to-end delivery to ensure error-free 2. Hub – interconnects networking devices but risks the broadcast Transport packets of data it receives to all devices connected to it. Session Establishes, manages, and terminates sessions 3. Switch – initiates a direct connection from the sender to the Presentation Manages protocol conversion and data translation destination bypassing the data traffic to ensure data privacy, Application Provides support for applications unlike a hub. It is best for interconnecting networking devices. Network Types and Devices 4. Cable Modem – uses a cable connection to create a broadband network connection from a home network to the internet service These are devices required for communication and interaction provider (ISP). This setup needs a splitter to divide the cable TV between components on a computer network, either wired or wireless. from the home network. Wired Network uses cabling and connectors to initiate network 5. Servers – provide resources, data, services, and programs to connections. other computers or clients over a network. It is tasked to handle complex operations such as databases, emails, and shared files. Wireless Network uses radio signals to initiate network connections. It is the most common home network configuration today. 6. Firewall – a security device that monitors and secures incoming and outgoing network traffic based on established security Network Type Advantages Disadvantages policies. It is essentially the barrier between a private internal network and the public Internet. Faster network data Specialized tools for transfer speed cable connections Wireless Network Devices Wired Inexpensive setup Labor-intensive 1. Wireless Access Point – connects wireless devices and provides Not susceptible to a connection to wired LANs. The data transfer speed for access outside interference points relies on the wireless technology of the clients. User mobility Security issues Wireless 2. Wireless Router – consists of a router, switch, and wireless Simple installation Slower data transfer access point that uses radio frequency to link networking devices. It is the most common way to connect wireless LANs to the ISP’s access device. 05 Handout 1 *Property of STI  [email protected] Page 3 of 4  IT2221 3. Wi-Fi Modem – combines the functionality of a modem and a It is one of the reasons why bus topologies are rarely used in router, thus making it a convenient source for Internet modern computer networks. connectivity. Star – the most common networking topology in LANs today, where all the devices connect to a central switch or hub. Various Network Topologies For example, the hub or switch supplies the network connection if Network Topologies a computer needs to send data to the laser printer. If a hub is used, the data is sent to the hub, which forwards it to the printer. LAN is described by the protocol and the topology used for network access. The networking protocol is the rule for users to exchange But a hub is a multiport repeater that broadcasts and displays the information. At the same time, the network topology is the physical data it receives to the devices connected. It also applies to all and logical arrangement of nodes such as a switch or hub and networking devices interconnected in a star network. connections in a network. Additionally, to lessen unnecessary data traffic and isolate The most common topologies for LANs are as follows: sections of a network, using a switch at the center of a star network is much more ideal than a hub. Point-to-Point – the simplest network topology where two devices, like a computer or router, are connected directly. With Mesh – it is when the networking devices are directly connected this, the communication only flows between the two devices. where several paths exist between the end devices. Token Ring – Its deterministic nature ensures access to message Mesh topology can be divided into two types based on paths; fully transmissions at regular or fixed time intervals for each connected meshed and partially meshed. If a direct path exists from each station. end device to other end devices in the network, it is a fully meshed topology. However, it is a partially meshed topology if multiple A disadvantage is that if an error changes the token pattern, it paths are observed between the end devices. might stop circulating, causing data traffic to stop. It is important to note that Ethernet technology has recently replaced token ring topology. References: Beasly J., Nilkaew P. (2022). Networking essentials: Sixth edition. Bus – occurs when computers share the media for data Pearson. transmission using a coaxial cable, preventing data transmission Cisco (2022). What is network architecture? [Web Article]. Retrieved from being extremely bandwidth efficient. on July 14, 2022, from https://www.cisco.com/c/en/us/solutions/enterprise- For example, if a computer prints a file, the data communication networks/what-is-network-architecture.html is only between the computer and the printer. But in a bus system, Ingalls, S. (2021). What is a server, and what do servers do? [Web each connected device can see the computer’s data traffic to the Article]. Retrieved on July 14, 2022, from printer. The other devices wait for pauses or halts before https://www.serverwatch.com/guides/what-is-a-server/#what-is- establishing their transmissions. a-server 05 Handout 1 *Property of STI  [email protected] Page 4 of 4