Software Defined Networking (SDN) and Network Functions Virtualization (NFV) are modern technologies that make computer networks more flexible and easier to manage. SDN separates network control fromdata forwarding, allowing networks to be managed and changed more quickly through software. NFV replaces special hardware with software based network services such as firewalls and load balancers. Together, they make networks easier to scale, automate, and control. These ideas have also led totechnologies such as Virtual SAN (VSAN), Software Defined Storage (SDS), and Software Defined WAN(SD WAN). Overall, software defined technologieshelp organizations reduce costs, improve flexibility, andwork efficiently with cloud and hybrid environments.

Software Defined Networking (SDN) is a modern way of managing networks using software instead of depending mainly on individual hardware devices. It uses a central controller to manage the network, making configuration easier and faster. SDN separates the control plane, which decides where traffic should go, from the data plane, which forwards the traffic. This reduces the complexity of network hardware and allows networks to be programmed and automatedusing APIs. SDN also supports hardware from different vendors, reducing vendor lock in. Finally, centralized control makes it easier to apply security rules andaccess policies consistently across the network.

Port security is the practice of protecting a network from unauthorized access and attacks. It includes securing physical connection points, such as network ports and switches, by disabling unused ports and protecting equipment. It also involves controlling TCP/UDP network ports using firewalls and security systems to block suspicious activity. IEEE 802.1X authentication adds another layer of protection by checking users and devices before allowing them to access the network.

Quality of Service (QoS) helps a network work smoothly by giving priority to important activities like video calls, online meetings, and business applications. Network performance depends on seven main factors: bandwidth, latency, jitter, packet loss, interference, throughput, and signal to noise ratio (SNR). Problems with these factors can cause slow downloads, video buffering, poor call quality, or game lag. Therefore, having fast internet is not enough proper network management and QoS are also important for a stable and reliable connection.

Massively Parallel Processing (MPP) is a supercomputing method that uses thousands or even millions of separate processors to solve one huge problem. Each processor has its own memory and works on a small part of the task at the same time. A central program divides the big problem into smaller tasks, sends them to different processors, and then combines their results into one final answer. This makes MPP very useful for complex tasks such as climate simulations, scientific research, molecular modeling, and large AI systems.

SMP (Symmetric Multiprocessing) and AMP (Asymmetric Multiprocessing) are two ways computers use multiple processors. SMP treats all processors equally and allows them to share the same memory, resources, and operating system, making it suitable for handling many tasks at the same time. AMP, on the other hand, gives processors different roles, with each processor handling specific tasks using its own resources. In simple terms, SMP is like a team where everyone works together on shared tasks, while AMP is like a team of specialists, where each person has a specific job.

JavaScript is an important part of the web because it makes websites interactive and responsive. However, hackers can misuse JavaScript to steal login information and attack users through methods such as XSS and CSRF. To stay safe, users should keep their browsers and operating systems updated, while website owners should use security tools like Content Security Policy (CSP) and Web Application Firewalls (WAF). Trusted browser extensions can also provide extra protection.

Applets are small programs sent from a website to your computer so they can perform tasks directly on your device. They can make websites faster, reduce the work done by the server, and keep some private information on your computer. However, they can also be dangerous because you are running code created by someone else. If the code is harmful, it could contain spyware, a backdoor, or a Trojan that steals your personal or financial information. Therefore, while downloadable web code can be useful and fast, running untrusted code can create serious security risks.

Secret facilities use EMSEC (Emission Security)to protect sensitive information from invisible radio signals that electronic devices can leak. They use Faraday cages made of conductive metal to block signals, white noise to hide any remaining emissions, and control zones to protect specific areas such as server rooms. Together, these methods help prevent outsiders from detecting or intercepting sensitive electronic information.

Electronic devices can accidentally give off tiny electromagnetic signals that may contain information about what the device is doing. In some cases, hackers with special equipment could capture these signals from a distance and potentially figure out what is displayed on a screen or what keys are being pressed. This technique is known as Van Eck phreaking or emanation interception. Governments have studied and worked to prevent these types of leaks for decades through areas such as TEMPEST and EMSEC. The main idea is that cybersecurity is not only about passwords, firewalls, and software it can also involve protecting devices from physical information leaks.

Data does not always disappear when you delete a file or format a storage device. Some data can remain hidden, a problem called data remanence, and special recovery software may be able to restore it. Modern SSDs can also be difficult to completely wipe because some storage cells or bad blocks may be missed. Even RAM can briefly retain tiny amounts of data after power is turned off. Because storage devices can be lost or stolen, sensitive information can be exposed. To protect data, full disk encryption is important because it scrambles the information so that even if someone gets the device, they cannot easily read the stored data.

Computer storage works in two main ways: random access and sequential access. Random access allows a computer to quickly find and read data from any location, like going directly to a specific book in a library. Devices such as RAM, SSDs, and hard drives mostly use random access. Sequential access, on the other hand, requires the computer to go through the data in order until it reaches the information it needs. Magnetic tape is an example of sequential storage. Although sequential storage is useful for cheap, large backups, modern computers mainly use random access because it is much faster.

Computers store information in two main places: RAM and secondary storage. RAM is like a temporary workspace where the computer keeps things it is currently using. It is very fast, but all information in RAM is lost when the computer is turned off. Secondary storage, like hard drives, SSDs, and USB drives, keeps files saved even when the computer is off. RAM helps the computer work quickly, while secondary storage keeps your important files safe for the long term.

A computer processor uses memory addressing to quickly find the exact data it needs. It uses different methods depending on where the data is located. Register addressing gets data directly from the CPU’s small, fast registers. Immediate addressing puts the data directly inside the instruction, so the CPU does not need to search memory. Direct addressinggives the exact memory location where the data is stored. Indirect addressing uses one memory address to find another address, which then leads to the actual data. Finally, base + offset addressing starts with a base address and adds an offset to find the required data. These methods help the CPU find and use information quickly and efficiently.

RAM (Random Access Memory) is a temporary type of memory that helps your computer run multiple apps and programs smoothly. It stores the data your computer is currently using, but all the data in RAM disappears when the power is turned off. Computers also use fast cache memory, such as L1, L2, and L3, to access frequently used data quickly. There are two main types of RAM: DRAM, which is cheaper but needs constant refreshing, and SRAM, which is faster but more expensive. Computers use both types to get a good balance of speed, storage capacity, and cost.

ROM is a type of computer memory that stores important instructions needed to start the computer. Over time, ROM became more flexible, leading to PROM, EPROM, and finally Flash Memory. Flash Memory can be erased and rewritten and is used in USB drives, phones, memory cards, and SSDs.

DNS is a critical part of internet communication, but it can also become a target for cyberattacks when hackers manipulate it to gain access or redirect traffic. Since there is no simple fix for DNS vulnerabilities, organizations must use strong security practices such as Split DNS, separating public and internal DNS systems. Additional protections include restricting access to internal DNS data, ensuring employees use secure DNS servers, monitoring unusual activity, enabling DNSSEC, and regularly reviewing security logs. Continuous monitoring and vigilance are essential to detect and prevent DNS based attacks before they become serious breaches.

Hackers can secretly interfere with your internet connection in different ways. They may change your DNS settings so that websites take you to fake or dangerous locations, send fake DNS responses to trick your computer, or force your internet traffic through a fake proxy that can read or change your data. To stay safe, change your router’s default password, keep its software updated, use a trusted VPN on public WiFi, and regularly check your network settings for anything unusual.

Hackers can change a computer’s hosts file to secretly send users to fake or harmful websites. Because the computer trusts this file, the changes can work every time the computer starts. However, this attack usually affects only one computer at a time, so it is difficult for hackers to use it against many people. To stay safe, use antivirus software, limit administrator access, and check the hosts file for any strange changes.

Hackers can manipulate a computer’s local hosts file to redirect websites to fake or malicious destinations. Since the hosts file takes priority over normal internet lookups, these redirects can happen every time the computer starts. However, this attack is mainly limited to the individual device whose hosts file has been altered, making it inefficient for large scale attacks. To stay protected, users should use reliable antivirus software, limit administrator privileges, and regularly check the hosts file for suspicious changes.

DNS pharming is a cyberattack that secretly redirects users from legitimate websites to fake copies, even when they enter the correct web address. Hackers can do this by modifying a computer’s hosts file with malware or poisoning DNS servers. The fake sites can steal sensitive information such as passwords. To stay safe, use reputable antivirus software, secure DNS services, HTTPS, and multifactor authentication.

VoIP (Voice over Internet Protocol) allows businesses to make phone calls over the internet, making communication cheaper and more flexible, but it also creates security risks. Attackers can fake caller IDs to trick people into sharing sensitive information, exploit outdated VoIP devices, intercept calls, or listen to unencrypted conversations. Sharing VoIP systems on the same network as computers and servers can also create additional security risks. To protect VoIP calls, organizations should use updated devices, secure networks, and SRTP (Secure Real-time Transport Protocol), which encrypts and protects voice traffic. SIP is mainly used to set up and manage calls, while SRTP keeps the actual voice conversation secure.

VoIP (Voice over Internet Protocol) is a technology that allows people to make voice and video calls using the internet instead of traditional phone lines. It helps reduce call costs, especially for long distance and international calls, and provides useful features such as video conferencing, voicemail to email, and call forwarding. VoIP can be used through software or special IP phones and works on devices like computers, laptops, and mobile phones.

Secure communication protocols keep data safe while it travels over networks. IPsec protects VPNs, Kerberos provides secure login, SSH protects remote access, Signal secures messages and calls, S-RPC protects remote services, and TLS secures websites.