Time
30 hours 46 minutes
Difficulty
Intermediate
CEU/CPE
20

Video Description

Spanning Tree Protocol (part 3) Root Ports In this final sub-lesson on Spanning Tree Protocol, we define and examine what happens with/to Root Ports and their states in the Spanning Tree Protocol process. We explain blocking, listening, learning and forwarding, what happens during each state, what time frames are involved, which have delays and why, which have data transmission and which don't. We'll also examine what happens when there is no destination address for a MAC address, and what impact if any that has on the MAC Address Table.

Video Transcription

00:04
Now we're going to see what happens to these rude ports,
00:08
these designated ports
00:11
and the ports that have nothing on top off them.
00:16
So poor one and pour two on switch for have neither designated no poor tree and port one on switch for have neither designated or root port on top of him.
00:29
So they're neither
00:30
wins, which is power off.
00:32
And as spanning tree is converging.
00:35
Initially, all ports are put in blocking
00:38
in blocking. No data traffic is being forwarded. Ofcourse, bpd use are being sent because spanning tree is converging
00:45
and this date lasts for 20 seconds. Next
00:52
you move over to listening
00:55
and during listening, you are sending and receiving bpd use
00:59
and you're rude. Bridge election is happening and your route port election is happening
01:03
and you're listening. Stage last for 15 seconds.
01:08
This 15 seconds. This 15 2nd timer is also known as the spanning tree for delay.
01:18
Then the port is transition to what is called a learning.
01:21
The learning state also
01:23
last 15 seconds, and this timer is also called for delay.
01:30
So both these timers are called forward delay
01:34
in learning
01:37
there is no data traffic flowing, but the switch is still populating its Mac address table.
01:42
What happens when a destination address does not exist in the Mac address table for a switch and the switch is signed before the frame to a particular Mac address. The switch floods the frame.
01:55
So
01:56
to reduce flooding. Once the switches do, start forwarding data traffic. You take these 15 seconds to populate the Mac address table as much as possible to reduce flooding once forwarding starts.
02:12
And after 15 seconds off
02:14
learning spent in learning the switch, start forwarding data traffic.
02:19
Now designated ports
02:22
and root ports are put in forging.
02:24
So this is designated fording,
02:28
fording,
02:30
fording,
02:32
fording,
02:35
forwarding,
02:36
fording,
02:38
fording
02:39
now non designated port
02:42
or alternate ports. In Cisco's vernacular, these are called alternate ports.
02:47
So poor three switch four is an alternate port
02:53
and pour one switch for is an alternate port because these provide an alternate packs to the route bridge.
03:00
Or you could call them non designated non route ports. These are put in blocking,
03:07
so
03:08
this link is shut down
03:12
and kind of running out of space. This link is
03:15
shut down.
03:17
So have me at this point stopped the loop.
03:21
Can I have a loop this way now?
03:23
No, I can't
03:23
because this sport is blocking.
03:27
Can I have a loop
03:28
this way or this way? No, because this port is blocking.
03:32
And that concludes the spanning three decision making process and spanning three convergence.

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Junaid Memon
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