In this lesson, we begin our exploration of the original Spanning Tree Protocol (STP), also known as the Common Spanning Tree (CST). Introduced in the 1990s, it allowed Ethernet LANs to have backup links without causing loops.

Wireless security can be tricky because it introduces a lot of short acronyms and terms. For example, this lesson covers the most common wireless client authentication methods and technologies. It includes terms like WEP, OSA, SKA, PSK, TKIP, EAP, WPA, WPA2, and WPA3.

Wired networks have an inherited level of security because data travels over physical wires, reducing the risk of eavesdropping. Wireless networks are different.

In this lesson, we will dive into the 802.11 frame addressing. It is essential to understand the differences between a standard 802.3 Ethernet frame and an 802.11 wireless one.

This lesson discusses why standards are essential in networking, why we need to have wireless regulatory bodies in different regions of the world, and the most common wireless standards.

In shared networks like wireless or wired Ethernet, multiple devices transmitting simultaneously can cause collisions. Collisions corrupt data, waste time, and require retransmission, which wastes even more time. 

Network engineers are typically pretty familiar with the Ethernet (802.3) frame format. It is the foundation of switched networks. To provide context for this lesson, let's first recall how it works and then compare it to the wireless 802.11 frames. 

Wireless devices are designed to be mobile. They will naturally move from place to place. This lesson explains how mobility works from the perspective of access points (APs) and controllers (WLCs).

Let's make a quick recap for context for the lesson: access points can work in two modes: autonomous or lightweight. In autonomous mode, the AP works on its own. In lightweight mode, the AP depends on a centralized wireless controller to function.

In this lesson, we will explore how lightweight APs operate, the role of the wireless controller (WLC), how CAPWAP tunnels function, and how client traffic flows through the network. Understanding this architecture is essential for understanding modern enterprise wireless networks.