Stream of Knowledge

  In this lesson, we explain   what the OSI model is   in an easy and understandable language. It is one of the most important concepts in networking, so we break it down into pieces to help you understand exactly what its purpose is. What is data encapsulation? To understand the OSI model, you must first understand what data encapsulation is. Let's explore the following example. Imagine you want  to send a letter to a friend  who lives in another city to invite him to your wedding. What if you send the letter without an envelope, with any information, such as the sender's and recipient's names, addresses, and postcodes? What if you simply write the letter and drop it in the mailbox at the post office?  Most readers of this CCNA course are so young that  they've never sent a physical letter in their lives . They live in the digital age and have grown up with emails and instant text messages. However, surprisingly, everyone understands the concept of th...

 How ARP Works: Understanding ARP Requests, Replies, and ARP Cache Address Resolution Protocol (ARP) is an essential protocol in the world of networking. It's responsible for mapping IP addresses to MAC addresses within a local area network (LAN). 🔄 How ARP Works When a host wants to communicate with another device, it needs the MAC address associated with the destination IP. If the MAC address is unknown, the host sends out a broadcast ARP Request asking: 🗨️ “Who has IP address X.X.X.X? Tell me your MAC address.” The device with the matching IP sends an ARP Reply with its MAC address, allowing communication to begin. 📨 ARP Messages ARP uses two packet types: ARP Request Destination MAC: FF-FF-FF-FF-FF-FF (broadcast) Target MAC: 00-00-00-00-00-00 (unknown) ARP Reply Uses unicast MAC addresses for both source and destination Header Fields Include: Source MAC and IP Target MAC and IP 🧪 Real-World Examples Host-to-Host on Same Network PC2 want...