When a computer receives data over a network, it faces an immediate challenge: multiple applications are running simultaneously — a browser, an email client, a file transfer tool — and all of them may be receiving data at the same time. How does the ...

**Theoretical Recap** The TCP (Transmission Control Protocol) three-way handshake is the foundational mechanism by which two hosts establish a reliable connection before any data exchange occurs. It operates at Layer 4 (Transport) of the OSI model an...

Now that you have explored the first three layers of the OSI model — Physical, Data Link, and Network — you have seen how data travels as electrical signals, how Ethernet frames are built, and how routers forward packets across networks using IP addr...

## Project Overview In this mini-project, you will consolidate everything you have learned about OSI layers 1 through 3 by tracing, capturing, and documenting the complete journey of a network packet from your machine to a public website. This is not...

THEORETICAL RECAP Traceroute is a network diagnostic tool that maps the path packets take from your machine to a destination host, revealing each intermediate router (hop) along the way. It works by sending packets with incrementally increasing TTL (...

THEORETICAL RECAP Traceroute (or tracert on Windows) is a network diagnostic tool that maps the path packets take from your machine to a destination host, revealing each intermediate router — called a 'hop' — along the way. It operates at Layer 3 (Ne...

INTRODUCTION AND POSITIONING IN THE OSI MODEL You have already explored Layers 1 and 2 of the OSI model. You know that Layer 1 (Physical) handles signals and transmission media, and that Layer 2 (Data Link) manages the framing of data, error detectio...

THEORETICAL RECAP An Ethernet frame is a structured unit of data that operates at Layer 2 (Data Link) of the OSI model. It carries a payload from one MAC address to another within the same network segment. A standard Ethernet frame contains the follo...

THEORETICAL RECAP An Ethernet frame is the fundamental unit of data at Layer 2 (Data Link) of the OSI model. When two devices communicate on a local network, data is broken down into frames before being transmitted over the physical medium. Each Ethe...

Now that you have explored Layer 1, which deals with physical signals, cables, and transmission media, it is time to move up one level in the OSI model. Layer 2, called the Data Link layer, sits directly above the physical layer and adds the first la...