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We need to dive into a topic that is going to impact our production networks

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for sure,

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because when we look at Spanning Tree protocol, it was designed in an era when

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networks were

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very dynamic.

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And so the assumption there was, hey, if the network changes by adding switches

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and maybe

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by reconfiguring switches that the Spanning Tree topology would change

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appropriately.

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But in modern networks, our topologies are pretty well established.

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We usually have a dedicated distribution layer and dedicated access layers.
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We usually have a dedicated distribution layer and dedicated access layers.

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And so if I connect an access layer switch to the network and it's configured

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with a

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Spanning Tree priority of zero, maybe it had been used in a lab or something

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along those

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lines and someone was practicing their CCNA or CCNP skills and they configured

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it with

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a priority of zero.

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And then we take that switch and plug it into the network, it's going to take

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over as the

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route, which is going to bring the entire network down while all of the ports

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go through listening

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and learning.

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Even rapid Spanning Tree, we'd notice that it would go faster, but we'd still
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Even rapid Spanning Tree, we'd notice that it would go faster, but we'd still

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have a

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lot of problems.

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And so Spanning Tree is unfortunately not going to help us out with native

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configurations.

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I can't tell Spanning Tree, hey, I want you to be the root no matter what.

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I can set you to priority zero, but if the switch I connected, which also has

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priority

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zero, has a lower MAC address, it'll still take over.

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And I can't tell Spanning Tree not to do that.

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So fortunately Cisco has come to the rescue for us.

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They've given us a series of mechanisms that we can use to protect the topology
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They've given us a series of mechanisms that we can use to protect the topology

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.

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We're going to cover three of them here in this skill.

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And the next skill we're going to find that Spanning Tree still has some

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potential scenarios

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that creates loops.

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And so we'll talk about mechanisms that can help us with additional loop

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protection.

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But our focus here in this skill is going to be saying, I want to build out a

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Spanning

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Tree topology and I want it to lock in place.

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Even if I connect a switch by accident and somewhere, I misconfigure a switch,
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Even if I connect a switch by accident and somewhere, I misconfigure a switch,

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or for

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that matter, if somebody is nefariously trying to cause my network harm, I need

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to be able

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to protect the network in those situations.

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And that's exactly what these mechanisms are going to do for us.