Original subtitles

Think about your P.C. today.

How long does it take your P.C. to boot up pieces today.

Don't take 30 seconds to boot up a lot of them are available within a few seconds or instantly.

That's a problem when we have technology such as spanning tree that take 30 seconds to converge and

forward traffic on a network what I'm going to do is power cycle the devices

and I'll put to the lab into simulation mode noticed the switch has now booted up interfaces are showing

orange.

So what happens now is if the P.C. sends a renew message that a DCP message is gonna be sent to the

switch and then it's going to be dropped until the ports go to Green.

So once the ports go to green the DOJ GP request message can be forwarded but previously that message

from P.S. 1 was dropped because of the ports were transitioning from listening to learning to forwarding.

So during that period of time DCP messages will be dropped by the switch so let's configure spanning

three port fast on the switch on which ports do I need to configure it.

I need to configure it on both the client ports and the server port.

We essentially want these three ports in this topology to transition to the forwarding state immediately.

Okay so here's the switch what I'm going to do is firstly give the search a name and then I'm going

to say interface range gigabit 1 0 1 2 3 those are the three ports in our network that have devices

connected to them.

So when say spanning tree.

And in this case we're going to select port first.

So Port Fost enter.

Notice we receive a warning message port Foss has been configured on this port.

You can introduce loops if you're not careful.

So use with caution but that's okay for this example.

So show run.

Notice we've enabled port fast on these three ports.

So what I'll do is save the switch configuration and what I'll do now is power cycle the devices

and what we should see is that as soon as the switch boots up the ports go to forwarding which they

have now and my piece he can receive an IP address immediately.

So again if I do IP config slash renew the peace he receives an IP address immediately the switch transitioned

immediately to the forwarding state on those three ports suspend entry immediately transitioned to the

forwarding state on those ports.

Let's do that again just to prove the point he has the switch.

It's busy booting up and what you should notice is as soon as it puts up vector the ports go green in

Packet Tracer.

There you go show spending tree.

Notice the ports are immediately forwarding and a P.C. such as P.S. 1 immediately receives an IP address

because of the DTP messages can be sent to the server immediately.

So there you go.

That's an example of spanning tree port Fost.

So what have you learnt you've learnt or that spending tree port forced transitions of Port directly

to the forwarding state instead of transitioning from listening to learning to forwarding with spanning

tree port fast ports configured as spanning tree port Foss ports immediately transition to forwarding

which means that pieces can get IP addresses from DHB servers.

Users can log in to services such as domain controllers without any delay and the network works more

efficiently.

It's important that you understand what spanning tree port Foss does for the CCMA exam.