CompTIA Network + "Full Course", Network Plus 2026

Computer networking is the practice of interfacing two or more computing devices with each other for the purpose of sharing data whether it is wired or wireless. Computer networks are built with a combination of hardware and software.

Any Smart device! That provide Information is also using computer Networking .

Internal Network Devices

•The Network Interface Controller (NIC) card plays very important role in our computer as it is the network adapter. Your internet connection comes through the NIC card as does all other network connectivity. The NIC card is a type of PCI expansion card as it is plugged into the motherboard’s PCI port.

•The Wireless Network Interface Controller (NIC) or card is network adapter in Wireless you not need plug wire backside on desktop or laptop. Your internet connection comes through the NIC adapter card allow network connectivity. you can install extra WNIC in desktop computer, but in laptop its already available.

•Bluetooth is a wireless technology standard for exchanging data over short distances, for example your smart devices such as mobile devices, Bluetooth is a transmits and receives information data with wireless signals, The Wireless Bluetooth USB Dongle Adapter plug on USB Slot of desktop ,you can plug in desktop computer, but in laptop its already Bluetooth available.

•Network Router; When a device in a Local Area Network needs to communicate with a device on another LAN, WAN, MAN, CAN, PAN it must send that traffic to a specialized device connected to the LAN called a “router” Router is interpreter in between network derives !

•A switch serves as a controller, enabling networked devices to talk to each other efficiently. A switches use to connect computers, printers, phones, cameras, lights, and servers in a building or campus.

Domain Name System (DNS) is used to match domain names to the IP addresses. DNS is provided over the intranet and internet servers with different port numbers.DNS can use both transmission protocols TCP and UDP. But general usage is over UDP protocol because of its simplicity and speed.

TCP Port 53

One of the used DNS port is TCP Port 53. TCP provides stability over the DNS resolutions process. With TCP 53 there will be no data loss over network transmission which makes DNS transaction more stable. But this will create some overhead for the server and client because of the TCP behavior.

UDP Port 53

The most known and popular usage protocol of DNS is UDP 53. Most DNS servers use UDP 53 port which provides simplicity and less resource usage.

•Public - DNS Server

•Private – DNS Server

•A web server is a computer that runs websites. It's a computer program that distributes web pages as they are requisitioned. The basic objective of the web server is to store, process and deliver web pages to the users. This intercommunication is done using Hypertext Transfer Protocol (HTTP/HTTPS). These web pages are mostly static content that includes HTML documents, images, style sheets, test etc. The main job of a web server is to display the website content. If a web server is not exposed to the public and is used internally, then it is called Intranet Server. When anyone requests for a website by adding the URL or web address on a web browser’s (like Chrome or Firefox) address bar (like www.google.com ), the browser sends a request to the Internet for viewing the corresponding web page for that address. A Domain Name Server (DNS) converts this URL to an IP Address (For example 192.168.216.345), which in turn points to a Web Server.

•Anyone who works in an office these days, even a virtual office, often will work with a print server. It is simply a device that allows computer workstations to interface with one or more printers that are shared on a network. Each station has the ability print or choose one of the printers on the network as its default printer, but may always choose to send a print job to any of the other printers recognized by the server.

•Types of Printer

•Network Printer ; that your connect through Network Cable

•Local Printer ; that you can connect through USB Cable

•Workgroup Environment

•Your personal computer can represent as a Workgroup Environments means that is your computer, you have full access of that computer by using admin account (Guest Computers !)

•Domain Environment

•When you join your computer to the Domain Environments, means you have not full access of that computer. That computer can be administrate by I.T Departments and that computer is member of Domain! Or Active Directory Central process System

The Open Systems Interconnection model (OSI model) is a conceptual model that characterises and standardises the communication functions of a telecommunication or computing system without regard to its underlying internal structure and technology. Its goal is the interoperability of diverse communication systems with standard communication protocols.

OSI model - Wikipedia

•1. Physical Layer

•It is the bottom-most or the first layer of the OSI Model

•It comprises the raw data which is further transmitted to the higher layers of the structure

•Preparing the physical devices in the network and accepting the received data for transmission

•The termination of connection between two nodes of a network also takes place at this stage

•This layer converts the digital bits into electrical, radio, or optical signals

•2. Data Link Layer

•Access to get the data is achieved at this layer

•It breaks the input data into frames which makes analyzing the data easier

•Ensures that the data received is free of any errors

•It controls the flow of data in the stipulated time duration and along with a set speed of transmission

•The data is sent to the next layer in the form of packets which are then reviewed for further processing

•3. Network Layer

•It acts as a network controller

•Transferring of variable data from one node to another, connected in a network, takes place at this layer

•Each node has a specific address and the network layer ensures that the data is sent to its destination address

•The data is sent in the form of fragments which are then connected to each other once the processing is done

•4. Transport Layer

•The delivery of data packets is managed by the transport layer

•It manages the flow of data, segmentation and desegmentation and error control

•There are five classes of the transport protocol, starting from 0 and continuing till 4 (TP0 to TP4)

•Fragmentation and reassembly of data packets occur that this stage

•5. Session Layer

•The connection between the computers connected in a network is managed at this layer

•Establishment, management and termination between the remote and local application takes place here

•Authentication and authorisation happen at this layer

•This layer can also terminate or end any session or transmission which is complete

•6. Presentation Layer

•The data is converted into the syntax or semantics which an application understands

•Before passing on the data any further, the data is formatted at this stage

•Functions including compression, encryption, compatible character code set, etc. are also done at this layer of the model

•It serves as a data translator for the network

•7. Application Layer

•The interaction with the user or the user application takes place at this stage

•When identifying communication partners, the application layer determines the identity and availability of communication partners for an application with data to transmit

1. Core Size:

   • Single-mode: Has a smaller core diameter, typically around 9 microns. This allows only one mode or path of light to propagate, resulting in less dispersion and allowing for longer distances.

   • Multimode: Has a larger core diameter, commonly around 50 or 62.5 microns. It permits multiple modes of light to propagate simultaneously, which can lead to modal dispersion (where different modes arrive at different times), limiting the distance it can transmit data effectively.

2. Light Source and Wavelength:

   • Single-mode: Usually uses a laser as the light source. It operates at a wavelength of around 1310 nm or 1550 nm.

   • Multimode: Typically uses LEDs as the light source. It operates at wavelengths around 850 nm or 1300 nm.

3. Distance and Bandwidth:

   • Single-mode: Can transmit data over longer distances, up to tens of kilometers to hundreds of kilometers, with higher bandwidth and lower attenuation, suitable for long-distance telecommunications.

   • Multimode: More suitable for shorter distances, typically up to a few kilometers, with lower bandwidth and higher attenuation due to modal dispersion.

4. Applications:

   • Single-mode: Often used in long-haul applications such as telecommunications, internet backbone connections, and cable TV.

   • Multimode: Commonly used in LANs (Local Area Networks), shorter-distance data communications, and applications where high bandwidth over shorter distances is sufficient.

5. Cost:

   • Single-mode: Generally more expensive due to the precision required for laser coupling and the technology used.

   • Multimode: Usually less expensive in terms of components and installation.

6. Fiber cable does not impact by EMI elector magnetic interface.

Here's where you can download VirtualBox Software

Downloads – Oracle VM VirtualBox

You have to make sue that CentOS is install without any error then go to terminal and types these commands

1---  sudo dnf makecache

2 ---  sudo dnf upgrade

3 --- sudo dnf config-manager --add-repo=https://download.virtualbox.org/virtualbox/rpm/el/virtualbox.repo

4 ---  sudo dnf install VirtualBox-6.1 –y

6 ---  VirtualBox

If you need VirtualBox Extension the follow the bellow commands _____

8 ---- wget https://download.virtualbox.org/virtualbox/6.1.6/Oracle_VM_VirtualBox_Extension_Pack-6.1.6.vbox-extpack

9 ---  sudo VBoxManage extpack install Oracle_VM_VirtualBox_Extension_Pack-6.1.6.vbox-extpack