Data Structure
Networking
RDBMS
Operating System
Java
MS Excel
iOS
HTML
CSS
Android
Python
C Programming
C++
C#
MongoDB
MySQL
Javascript
PHP
Economics & Finance
Positive Acknowledgement with Retransmission (PAR) is a group of error-control protocols for transmission of data over noisy or unreliable communication networks. These protocols reside in the Data Link Layer and Transport Layer of the OSI model. They provide automatic retransmission of frames that are corrupted or lost during transit. PAR is also called Automatic Repeat Request (ARQ). PAR protocols are used to provide reliable transmissions over unreliable network services. They are commonly implemented in wireless communication systems like GSM networks, where signal interference and packet loss are frequent challenges. Working Principle In PAR protocols, the receiver sends ... Read More
The Logical Link Control (LLC) is the upper sublayer of the data link layer in the OSI reference model. It acts as an interface between the network layer and the medium access control (MAC) sublayer of the data link layer. The LLC sublayer is primarily used for its multiplexing capabilities, allowing multiple network protocols to operate simultaneously within a multipoint network over the same network medium. LLC Layer in the OSI Model The data link layer is divided into two sublayers to handle different aspects of data transmission: Logical Link Control (LLC) sublayer − ... Read More
Elementary data link layer protocols are fundamental communication protocols that establish reliable data transmission between directly connected nodes. These protocols handle frame delivery, error detection, and flow control at the data link layer of the network stack. Elementary data link protocols are classified into three categories based on their complexity and capabilities: Protocol 1 − Unrestricted simplex protocol Protocol 2 − Simplex stop and wait protocol Protocol 3 − Simplex protocol for noisy channels Unrestricted Simplex Protocol The unrestricted simplex protocol represents the most basic form of data transmission. Data flows in one direction ... Read More
Security breaches have become a critical challenge for modern organizations. Price Waterhouse Coopers' "The Global State of Information Security Survey 2018" reveals that over 32% of 9, 500 interviewed executives believe their product quality is vulnerable to damage, while 39% are concerned about the loss or compromise of critical data. With cybersecurity affecting company reputation and business continuity, leaders like Tesla's Elon Musk prioritize security as more than just an IT issue. This has led to increased demand for ethical hackers who can proactively identify and fix vulnerabilities before malicious attackers exploit them. What is Ethical Hacking? ... Read More
In today's fast-paced world, Near Field Communication (NFC) has revolutionized the way we interact and connect with electronic devices. As a short-range wireless connectivity technology, NFC enables communication between two electronic devices over a distance of 4 cm or less, making tasks like contactless payments swift and secure. NFC operates at a frequency of 13.56 MHz and uses electromagnetic induction to establish communication. Unlike other wireless technologies, NFC can interact with both powered devices (like smartphones) and unpowered devices (like passive NFC tags embedded in posters or stickers). NFC Communication Range and Process ... Read More
The B-ISDN (Broadband Integrated Services Digital Network) is a virtual circuit-switched network that can use high-speed packet switching services. B-ISDN uses a flexible multiplexing format called ATM (Asynchronous Transfer Mode) to deliver broadband services over digital networks. B-ISDN represents an evolution from the original ISDN, designed to handle high-bandwidth applications like video conferencing, multimedia communications, and high-speed data transfer that require significantly more capacity than traditional voice services. B-ISDN Service Classification Interactive Services Distribution Services ... Read More
Data link layer translates the physical layer's raw bit stream into discrete messages called frames. The key challenge is determining how a frame can be transmitted so the receiver can recognize the start and end of each frame. Frame Delimitation Techniques The techniques used to identify frame boundaries are: Character count − Uses a header field to specify frame length Flag byte with byte stuffing − Uses special delimiter bytes Starting and ending flag with bit stuffing − Uses bit-level delimiters Encoding violation − Uses invalid signal patterns as delimiters Character Count Method ... Read More
In networking, routers and switches operate using distinct functional layers called planes. The two most important planes are the control plane and the data plane, each serving different but complementary roles in network operations. Control Plane The control plane is the "brain" of network devices that makes intelligent decisions about how data should flow through the network. It handles routing protocols, maintains routing tables, and establishes communication paths between network devices. Key functions of the control plane include: Routing protocol processing − Running protocols like OSPF, BGP, and RIP to exchange routing information ... Read More
A hub is a networking device used to connect multiple devices in a network, creating a single collision domain where all connected devices share the same bandwidth. Hubs operate at the Physical Layer (Layer 1) of the OSI model and simply repeat incoming signals to all connected ports. There are three main types of hubs based on their functionality and features: Passive Hub Passive hubs are the simplest networking devices that contain no electronic components or signal processing capabilities. They act as simple connection points that physically join network cable segments together without amplifying or regenerating signals. ... Read More
The Physical Layer Coding Violation is a framing technique used in data communication to identify frame boundaries by intentionally violating the normal encoding rules of the physical layer. This method leverages the redundancy built into certain encoding schemes to create distinct markers for frame delimitation. How It Works This technique is specifically used in networks where the physical medium encoding contains redundancy, such as in Manchester encoding. In Manchester coding, each data bit is represented by two physical bits, creating natural redundancy that can be exploited for framing purposes. Manchester Encoding and Coding ... Read More