Switch Priority, Port Priority, Path Cost and STP Timers Part 1

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3 hours 35 minutes
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Hello there and welcome to this Cisco CC and he switched 301 15 Exam prep series. My name is full pension Ali on in Today's episode will focus on the switch priority Port priority pot costs on STP timers Spark one.
We can show on spine entry in a number of ways. One such way would be by changing who would become the Woodbridge in our switch network. Often times you would wanna control who is the route bridge within your network.
You would also want to help farts convergence with airports whenever you plug a new device Interior Network. The switch priority by default. It started 2760 plus the system, maybe extension, which is normally the villain number. So if, for example, you have Dylan 10
for that exponentially instance, the priority then will be toward the 2760th plus the 10 which represents Villain 10 given us a priority value off Charlie 2778. The switch with the lowest bridge I ity becomes the route bridge within a switch network.
The Bridge I D is made up of a switch priority on a mock address of the switch.
We can tweak this rich priority from global configuration with commander spanning tree villain on. We would specify the villains,
which we want to change the switch priority on then with specified a value. Another way of changing the switch priority is by using a macro by using a key word route on. Any would specify either primary or a secondary, but note this would only change a priority on a one time basis. Say, for instance, another switch comes in with a lower priority
stand up,
which was set with the macro. Then a switch would not outdated switch priority to be lowered on a new switch, which was added with a lower priority. She would money love the change your Woodbridge priority if he used the macro to settle the wood, which so the safest way is the hard court in it, with a priority
keyword AnAnd, specifying your priority. For example, priority or zero would insure that switch always becomes the route bridge by default. Report. Priority is 120 when a switch goes to select a route, port the forward traffic to the root bridge. If the pot costs equals between two ports going up to the route bridge and the port priority
becomes a tiebreaker on the port with the lowest port priority becomes the Route port going up to the road bridge.
You can also affect downstream switches with port selection by locally altering the port hierarchies that are going on to the switch. Save the dung streams, which has two connections to the local switch, and you can also one of the two ports locally toe have a lower priority. This would, in effect, influence the Dong Stream Switch route
Election. Also note all ports in the root bridge, our forward in on their known as designated ports. In this diagram, which one is the route on all of switch one? Ports are designated ports connected to switch one. We have switched to ones with three. I've also added some costs from switched to perspective. It has two parts. You can use the reach
the route bridge. It can use either directly connected pot
or it can use the bat. True sweet treat. Likewise, which we has two parts that can use the directly connected path. Or it can use apart true switch to note because the total part causes less between a directly connected interface on switch to one's retreat, which two is going to choose the directly connected port on that port is gonna become the report
like white sweet tree is going to choose. It's directly connected port and that point would become the route port.
Now we three switch twins with three. This connection is known as a land segment on the switch that is closest to the road bridge. In this case, which to port would be elected a designated port on Arianna. Report what? Elected as alternate port, which would, in effect, block this end of the port. No. What about him? We have switched for connecting the switch to which four has to Ling's connecting switch toe
by default. The part causes gonna be equal in this case. Likewise,
it's only one bridge says one e one bridge I t switch for can compare with. So the tie breaker is gonna be the port priority. In this case, we can set the bottom link with a lower port priority on as it is receiving switch four Switch four would choose the bottom link on the bottling would become the route port. Likewise, the top links role would change the alternate.
On the other end of a link
would be the designated port. The lower pod cost this before it. The cost of a port is determined by it in two fierce Bonwit. If multiple switches have the same part cost to the route bridge than a switch with the lowest virginity would be used. You can influence a route port selection by lower in the path cost in a link.
If the same switch has multiple links go into the root, which then the port priority would be used as disgusting. Previous laid.
We have a list here of some common part costs. You can change the SPD timers from their default values by default for DeLay. Timer is 15 seconds. Hello, timers. Two seconds. The Max H timers. 20 seconds. You may want to tweak these values. The speed up convergence from global configuration mood.
We can set the forward the late like why is the hello timer on a max h for either the villain
or the mst instance? I'm gonna bring up a lot. No. So we can see how we could work with the various switch priorities. Badcause on port hierarchies. In addition to the SPD timers,
we have tree switches here.
I have set up MST between and weak or one on an OIK orto and y axis. One is running a traditionalist financially or PTSD plus. Currently and white core. One is the root, which for the MST instance one will configure and why court, too
Toby the road, Which, for mst instance one forced. Let's look a conflict for N y core one and record to one and why access one Currently Reliance 80 to 90 year month.
The instance. One on when I run the show responding tree mst one. It says this, which is the root for MST. Instance one. In addition to this on the rule,
we can see all the ports I designated not under the far Signet 10 slash 22 interferes. It says sheer under the type column. On it, says bung, the P V S t.
So mst is backwards compatible that all responding tree moods. Why it say's shear. It is because I've changed a duplex on anti access one port connecting to and like or want tohave duplex. Let's go over quickly and white access one.
In here we can see the conflict
duplex at the health on on N Y. Access one's End, its run in traditional spine entry. And it says the report is fascinating. It 06 24 and we can also see shared here on this oughta end so no will configure and why court to to be the Route bridge
for the MST ones. Instance we're getting these errors because we have not hard coded conflict on the interview is going on and why Access wants him so hard core to convict not to change the route, which I would use a common, inspiring free MST. And then I'm going to specify the instance. If I was changing the rude, rich priority for the villain
instead of amnesty, I would use villain, as we have seen on the slates. But in our case, we're using MST, so I'm gonna specify MST one. No way can specify
either the macro keyword by using route or the priority keyword. I'll choose priority on after specified increments in values from zero increment in by 4096. In our case, al you zero no one around the show's finding free MST one. Now you'll see it says this switch for amnesty. One is the route on our reports.
I said. The designated Harry concedes his dispute.
This will change once. Convergence the X Place you'll notice. No. Previously, both ports going overto and white court was forward in traffic and had the designated role. Now one of the port has gone into the alternate state and is blocking. I no longer sees that this which is the root, which instead it shows
the mark address off. And why course, too, along with the priority now. The next feature we want to look at is a port priority feature. Let's say one this interface
the 10 still explaining foreign affairs to be the root port instead of the fast Ethernet 10 slash 20 tree. So I lowered a priority from and why course to perspective, amount specified. Instance.
I'll choose sport. Priority will choose 16. Now you'll notice the local ports. Parity has been changed from 1/20 which is the default to 16. No, let's go back to and like or one wonderful know you'll notice. Previously, we had the faceted 10 size 24 Interferes
was blocking and it had the alternate rule. No, it's in the forward in state, and it has the route rule how we can see these poor charity values. You can choose the details option on if we scroll a bit to the right part of fast eating at 10 slash Twain entry interface, it's receiving a poor priority value of 128 and for the Farsi. And that 10 slash 24 interferes.
It's receiving a poor charity value off 16
from afar in on. This is the local port priority. Here. We can see it is 120 it I'm going to stop the episode here, so I'll see you in part two of this episode. This is Philip occasionally, and when Thank you, which is in cyber
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