All righty, Welcome back, everybody, this is now multi layers switching multi layer switching, okay. Now we already know the switches can for frame based on layer three and layer four. Now we know in a layer three switch and not all are equal because based on their iOS, okay, you have to turn on IP routing. Not all by default, so you got to turn it on. So once you turn on IP routing, then you can go ahead and use your protocol you put your networks or higher you know, whatever format that protocol calls for. Maybe it's rip, you know, router rip, version two network, classical boundary network, classical boundary, normal summary, you're done.

You do it to all the switches, but yes, definitely. It will use layer three or layer four. Now obviously like I put it on there, layer two, it's happening anyway. Okay, because it There is a switch that has routing capabilities. But it's a switch. So layer L is dealing with frames.

So obviously layer two of the OSI is going to come go and come in at the same time. Okay. Now there's different types of multi layers switching. Route caching is not what we want. There is slow, goes, if you look at this, it has to examine each new traffic flow and setup shortcut entries on the switch engine. So imagine every frame that goes in there, it gets examined, and then gets put away.

And then guess exam, you know, it's got to go through this process. Okay for it to send information out. This technique is not used before packets, but it will generate traffic flow. So rock caching is really not the way to go. Whether you're a router, or you're a layer three switch. It's, you don't want to do that.

Like I said, Here, this This thing is not used to route packets but more for information statistics. Okay. The other type is topology based. This is where routing comes in because it uses something called Cisco Express forwarding. Ah, we've heard that one before Sef. So, what does it do all right in process running on the switch, download the current routing table database into the forwarding information base, the Fed right area of the hardware and you take in MPLS that should sound familiar to you.

Okay, Sef rip all that stuff, okay. It will have that in there. So it will make large decisions based already in within that database. So now we can go ahead and route okay and route quickly, because it already has information. There doesn't have to examine each little frame that comes in and put it you know, through this writing process, and then take it to the surgeon. No.

Doesn't do none of that. Okay, so it has already the database already that gets formed. Everybody knows, right? That's why it's called Cisco Express forwarding. Now forward information quickly, quickly. All right.

So this is the tail that we want to use, which is topology base. So again, two types topology based, and you have raw caching. No wonder you don't want to use, okay, and we know that Cisco catalyst switches can do layer three or layer four, and from layer two to layer four, they're using it, right, they're using layer two period at all times. layer three is a layer three switch. And then you go ahead and enable IP routing and configure our routing protocol. Then you'll you'll see that come into play.

If you don't do that, then you definitely won't see come into play us using a layer three switches a layer two switch, lets me know I got a router with a router will have a router that will layer three switch. Okay, that's what it is it has routing capabilities. And depending on what type of routing you're doing, you know they can go very quickly or they can go very slowly. Okay, so it all depends on network design, okay, and what you choose for that switch to use, but that's it. That's it. That's all you need to know about multi layer switching.

We're going into much deeper topics, of course, later on in this section. So I hope to see you there