In this lesson, we discuss a spanning-tree feature called PortFast. It is used to optimize the ports that connect to end-user devices by skipping the Listening and Learning state and directly putting the ports to Forwarding.

In this lab, we discuss how we customize the spanning-tree loop-free topology. Typically, most real-world switching environments only select the placement of the root bridge and leave all other settings at their default values.

In the previous section of this course, we examined the classical per-VLAN spanning tree (PVST+), which is based on the original STP (IEEE 802.1D).

In this lesson, we will go though the process of configuring different spanning-tree topologies per VLAN.

This lesson begins our discussion on Cisco's PVST (Per-VLAN Spanning-Tree) and PVST+ protocols. First, we are going to examine the inefficiencies of the original STP, and then we are going to show what improvements PVST brings to the network.

The lessons so far should be enough for you to understand how the original Spanning Tree protocol works (IEEE 802.1d). However, to really have a deep understanding that will stick with you for a long time, you must practice! 

In the previous several lessons, we discuesed how the spanning tree protocol calculates the loop-free topology and how it works in a normal, stable situation. In this lesson, we will examine how the protocol behaves when a topology change occurs and it must reconverge.

In the previous lesson, we discussed the Spanning Tree port roles. Let's make a quick recap:

In this lesson, we begin our discussion of the Common Spanning Tree algorithm. We walk through the process of how the protocol works and what kind of messages it uses to exchange information between switches. Let's get started.