From the course: Deploying Layer 2 Switching for Cisco Networks by Pearson

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Per-VLAN Spanning Tree (PVST) and PVST+

Per-VLAN Spanning Tree (PVST) and PVST+ - Cisco Tutorial

From the course: Deploying Layer 2 Switching for Cisco Networks by Pearson

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Per-VLAN Spanning Tree (PVST) and PVST+

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So in this lesson, I'm going to talk about spanning tree and why we had the need to evolve it into like a per-VLAN spanning tree. So the original 802.1d specification allowed for only one spanning tree topology to exist for the entire switch. Now this can also be referred to as a common spanning tree instance or CST instance. So in this case, you can see that we have traffic that is being blocked between PC A and PC B, between switch two and switch three. And that's fine because most of the traffic within an enterprise organization is going to be from the PCs to the servers, and they're going across a path that is not blocking. But what if we had another set of devices that was plugged in that same infrastructure? What if we had an environment where we're using security cameras and the security guard was a different location than the cameras. Well, if we stayed with a CST or a one spanning tree instance, we can't modify the traffic flow. So for the security guard, he could view the…

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