All language subtitles for Free-CCNA-DTPVTP-Day-19-CCNA-200-301-Complete-Course_en

This is a free, complete course for the CCNA.

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In this video we will cover two Cisco proprietary\n

and VTP, VLAN trunking protocol.

As I said, they are Cisco proprietary, meaning\n

DTP and VTP were removed from the CCNA exam\n

However, it’s important to know their function,\n

on the exam even though they are not on the\ntopics list.

So, what will we cover in this video?

We will cover DTP, dynamic trunking protocol,\nfirst.

DTP is a Cisco proprietary protocol that allows\n

switchports to be either access ports or trunk\n

Then we will cover VTP, VLAN trunking protocol.

VTP is another Cisco proprietary protocol\n

switch, which then acts as a server that other\n

have to configure VLANs on every single switch\nin the network.

Also, make sure you watch until the end of\n

a question from ExSim for CCNA, by Boson Software.

ExSim for CCNA is Boson’s set of practice\n

as the best practice exams to get you ready\nfor the real thing.

I used them myself for my CCNA and CCNP.

If you want to get a copy of ExSim, follow\n

Let’s go over some points about DTP.

DTP is a Cisco proprietary protocol that allows\n

interface status (access or trunk) without\nmanual configuration.

Basically, two Cisco switches connected together\n

will automatically be an access port.

DTP is enabled by default on all Cisco switch\ninterfaces.

Once again, because it is a proprietary protocol,\n

So far, we have been manually configuring\n

If we use DTP, we don’t need to enter these\ncommands.

Now, for security purposes, manual configuration\nis recommended.

DTP should be disabled on all switchports.

DTP can be exploited by attackers, and I’ll\n

this course, but for now just know that it\n

Let’s go straight into the CLI.

I’m in interface configuration mode here\n

MODE, followed by the question mark.

You can see the ACCESS and TRUNK options we\n

look at now is this one, DYNAMIC.

It says ‘set trunking mode to dynamically\n

So, I entered DYNAMIC and used the question\nmark again.

There are two options, AUTO and DESIRABLE.

The only description given is ‘Set trunking\n

or DESIRABLE’, which doesn’t really explain\ntheir function.

So, let me explain each of these modes.

A switchport in DYNAMIC DESIRABLE mode will\n

It will form a trunk if connected to another\n

switchport mode dynamic desirable, or switchport\n

SW1 and SW2 are connected via their G0/0 interfaces.

SW1’s G0/0 interface is in DYNAMIC DESIRABLE\nMODE.

SW2’s G0/0 interface is manually configured\nas a trunk.

So, these two switches will both agree to\noperate as trunks.

Here is a new command, SHOW INTERFACES G0/0\nSWITCHPORT.

These are just the first few lines of output,\n

It says switchport: enabled, because it is\na layer 2 port.

If we want to configure a routed port with\n

The administrative mode is dynamic desirable.

Administrative mode is what we actually configured\n

mode, displays whether it is a trunk or access\nport.

Because SW2’s interface is a trunk, SW1’s\n

Here on SW2 you can see that both the administrative\n

Now both interfaces are configured in dynamic\ndesirable mode.

So, they will both form a trunk.

The output of SHOW INTERFACES SWITCHPORT is\n

an administrative mode of ‘dynamic desirable’,\n

because both switches are actively using DTP\n

Even if manually configured as a trunk, an\n

This time SW2’s interface is configured\nin dynamic auto mode.

A switchport in dynamic auto mode does not\n

It will tell SW1 ‘if you want to form a\n

going to actively try to form a trunk with\nyou.’

However, because SW1 is in dynamic desirable\n

SW1’s SHOW INTERFACES SWITCHPORT output\n

mode of dynamic auto, and again an operational\nmode of trunk.

One more example: SW2’s interface is now\n

the SWITCHPORT MODE ACCESS command.

SW1 is actively trying to form a trunk, but\n

mode, the trunk will not form, and both will\n

The output of SHOW INTERFACES SWITCHPORT on\n

What does ‘static access’ mean?

‘static access’ means an access port that\n

(unless you configure a different VLAN).

There are also ‘dynamic access’ ports,\n

VLAN depending on the MAC address of the connected\ndevice.

But this is out of the scope of the CCNA, you\n

ports, I just wanted to clarify what ‘static\naccess’ means.

Now, on SW2’s g0/0 interface both the administrative\n

Okay, now you’ve learned about dynamic desirable\n

desirable mode will use DTP negotiation to\n

the other device is in trunk, dynamic desirable,\n

However, if the other interface is in access\n

Now let’s look at dynamic auto mode.

A switchport in dynamic auto mode will NOT\n

switches, however it will form a trunk if\n

It will form a trunk with a switchport in\n

or switchport mode dynamic desirable.

So, SW1’s G0/0 interface is configured in\n

Therefore, DTP negotiation will cause them\nto form a trunk link.

Here you can see the administrative mode of\n

Now, we already saw what happens when a switchport\n

in dynamic desirable mode, they form a trunk.

So, let’s look at two switchports in dynamic\nauto mode.

Neither is actively trying to form a trunk,\n

And they have the same output for the SHOW\n

mode of dynamic auto and operational mode\nof static access.

Next up, dynamic auto and access mode.

As you can probably guess, this will result\n

Here is the output of SHOW INTERFACES SWITCHPORT\non each switch.

Now, you may wonder what happens if a manually\n

Well, since both are manually configured,\n

Here is the output of SHOW INTERFACES SWITCHPORT\nfor each.

However, this configuration does not work,\n

will not pass between these switches.

Here’s a chart summarizing the resulting\n

For example, a switchport in dynamic desirable\n

any administrative mode except access.

Pause the video here if you want to take a\nlook at this table.

DTP will not form a trunk with a router, PC,\netc.

The switchport will be in access mode.

So, if you want to configure router on a stick,\n

connected to the router as a trunk, you cannot\n

Let me cover a few more points about DTP.

On older switches, switchport mode dynamic\n

They will actively try to form trunk links.

However, on newer switchers, switchport mode\n

You can disable DTP negotiation on an interface\n

If you use this command, the interface will\n

By the way, configuring an access port with\n

It will also stop sending DTP frames.

If you manually configure an interface in\n

sending DTP frames, unless you also issue\n

As I said before, it is recommended that you\n

configure them as access or trunk ports.

Now let me talk about trunk encapsulation negotiation.

Switches that support both dot1q and ISL trunk\n

This negotiation is enabled by default, as\n

trunk encapsulation negotiate.

I mentioned this in a previous video on VLANs.

If you want to manually configure a trunk\n

and ISL, you must first change the encapsulation\n

ISL is favored over dot1q, so if both switches\n

By the way, the DTP frames that DTP uses to\n

or in the native VLAN when using dot1q.

The default native VLAN is VLAN1, however,\n

will be sent in VLAN1 for dot1q also.

To show you this negotiation of trunking encapsulation,\n

I set the interfaces on both switches to dynamic\n

Notice that the default trunking encapsulation\n

By the way, this field down here, negotiation\n

whether the interface is sending DTP frames\nor not.

If the interface is in dynamic desirable,\n

If it’s in access mode, or if you use the\n

Okay, that was a good deal of information\nabout DTP.

I’m quite sure that you won’t need any\n

If you need extra review, watch the section\n

tracer yourself, and then try my packet tracer\n

Next, let’s move on to today’s second\n

VTP allows you to configure VLANs on a central server switch, and

VTP clients) will synchronize their VLAN database\nto the server.

It is designed for large networks with many\n

each VLAN on every single switch.

However, like DTP it is rarely used, and it\n

I will show you one reason why it is recommended\n

There are three versions of VTP, 1, 2 and\n3.

Most modern Cisco switches support all three,\n

I will talk about some differences in each\nversion as we go.

There are three VTP modes that a switch can\n

Cisco switches operate in VTP server mode\nby default.

Let’s talk about the different VTP modes.

First up, VTP servers. They can add, modify, and\ndelete VLANs.

As I said, Cisco switches operate in VTP server\n

database on Cisco switches by default.

They store the VLAN database in non-volatile\n

This means the VLAN database is saved even\n

VTP servers will increase the REVISION NUMBER\n

This revision number is a very important part\nof VTP.

It’s what VTP uses to determine the newest\n

that the switches will synchronize to.

VTP servers will advertise the latest version\n

the VTP clients will synchronize their VLAN\ndatabase to it.

So, VTP advertisements aren’t sent on access\n

Here’s another important point: VTP servers\n

It means that a VTP server will synchronize\n

number, because the highest revision number\n

Now let’s talk about VTP clients a little.

VTP clients cannot add, modify, or delete\nVLANs.

If you try to add, modify, or delete a VLAN\n

VTP clients do not store the VLAN database\n

VTP clients will synchronize their VLAN database\n

I will talk about VTP domains soon.

Finally, VTP clients will advertise their\n

to other clients over their trunk ports.

Okay, that’s enough information for now.

I will talk about the third VTP mode, VTP\ntransparent, later.

So let’s look at how VTP works.

These are four switches, and I’ve configured\n

will send and receive VTP advertisements between\neach other.

Here is the output of a very useful command,\n

All of these switches have the default configuration,\n

Let’s look at some of these fields.

These fields here shows that the switch is\n

but it is running version 1 at the moment,\nthe default.

Notice that there is no domain name.

By default the domain name is NULL, there\nis no domain name.

If we want VTP to synchronize among these\n

with the same VTP domain name.

You can see the default VTP operating mode\nof server.

Notice the maximum number of VLANs supported\nlocally is 1005.

This is because VTP version 1 and version\n

Only version 3 supports them, so if you want\n

The number of existing VLANs is 5, those are\n

Finally, look at the configuration reivision\nnumber.

If I add, modify, or delete a VLAN this will\n

to VTP clients in the same domain.

It will also update its own VLAN database\n

revision number, because VTP servers function\n

So, I used the command VTP DOMAIN CISCO to\n

I then made a vlan, VLAN10, and named it engineering.

So, because I added a VLAN, if I do SHOW VTP\n

You can now see that the VTP domain name has\n

is 6, and the revision number has increased\nto 1.

Now let’s go check on the other switches.

Okay, so something interesting has occurred.

Without any configuration, SW2 has changed\n

database to match SW1’s, with a revision\nnumber of 1.

If a switch with no VTP domain (or domain NULL)\n

name, it will automatically join that VTP\ndomain.

So, SW2 automatically joined the domain cisco.

As I said before, If a switch receives a VTP\n

a higher revision number, it will update its\n

If I do SHOW VLAN BRIEF on SW2 now, you can\n

Here you can see that the advertisements were\n

joined the domain and updated their VLAN database\nas well.

Since you’ve seen how VTP sync works, let\n

an old switch with a higher revision number\n

all switches in the domain will sync their\n

This could cause all of the hosts on your\n

the switches could sync to a totally different\n

This is one reason why VTP is usually not\n

Just to demonstrate that, let’s say this\n

5, and VLANs 1, 10, 20, 30, and 40.

Then you take an old switch your company used\n

has a revision number of 50, and VLANS1, 99,\nand 220.

It will send VTP advertisements with this\n

All of these switches will update their VLAN\n

10,20,30, and 40 will suddenly lose connectivity.

Next let me talk about VTP transparent mode.

Switches in VTP transparent mode do not participate\n

VLAN database to the VTP server.

VTP transparent mode maintains its own independent\n

It can add, modify, or delete VLANs, but they won’t\n

Although it doesn’t sync its VLAN database,\n

trunk ports, if the VTP advertisement is in\n

So let’s compare the functionality of server,\n

I set SW2 to client mode with the command\nVTP MODE CLIENT.

Afterward, I tried to create VLAN20 on the\n

because SW2 is now in client mode.

Then I set SW3 to transparent mode with VTP\nMODE TRANSPARENT.

Also, to show you that a transparent mode\n

in a different domain, I changed the domain\nname to juniper.

So, I created VLAN 20, named sales, on SW1\n

Then I did show vtp status, and you can see\n

It should be 2 I think, but I made a few other\n

Anyway, let’s see check out SW2.

As you can see, the VTP client SW2 has indeed\n

now has the same revision number, 4.

How about the transparent switch, SW3?

As expected, on the transparent switch SW3,\n

Changing the VTP domain to an unused domain\n

Changing the VTP mode to transparent will\n

So, if you’re going to plug an old switch\n

that uses VTP, make sure to reset the revision\n

it doesn’t overwrite your network’s VLAN\nconfigurations.

Now, the question is whether SW4 will have\n

Remember, SW3 is in transparent mode in a\n

the VTP advertisements to SW4.

Indeed, SW4 does not have VLAN20, and it is\n

So, what can we do to make SW3 start forwarding\n

If we change the VTP domain on SW3 back to\n

to SW4, even though SW3 itself won’t sync\n

So, I changed the VTP domain on SW3 back to\ncisco.

I also created some new VLANs on SW1 to increase\n

by the way, and now you can see that SW3 did\n

and SW4 synced its VLAN database to SW1 and\nSW2.

Finally, I’ll just talk about VTP version\na little bit.

To change the VTP version, use the VTP VERSION\ncommand.

Changing the VTP version increases the revision\n

this new revision number will be sent.

Other servers and clients will then sync and\n

For example here is SW4, it is now running\n

As for the difference between VTP version\n

from Cisco: VTP V2 is not much different than\nVTP V1.

The major difference is that VTP V2 introduces\n

If you use Token Ring VLANs, you must enable\nVTP V2.

Otherwise, there is no reason to use VTP V2.

Token ring is an old technology, so really\n

As for version 3, it has quite a few differences\n

the scope of the CCNA, so we’ll leave it\nhere.

Okay here’s the first slide on VTP again.

To be honest, there is still lots more I can\n

Again, it isn’t on the exam topics list,\n

VTP and its purpose, so I wanted to tell you\n

If you learn and remember the information\n

that should be more than enough for the CCNA\nexam.

Basically, just know the purpose of VTP, the\n

mode, know that switches operate in server\n

clients too, and know about revision numbers.

If you know all of that, you should be fine.

So before moving on to today’s quiz let’s\n

We looked at DTP first, which is a protocol\n

with other Cisco switches, without manual\nconfiguration.

However, it’s recommended that you disable\n

Then we looked at VTP, another Cisco proprietary\n

on switches that operate as central VTP servers,\n

and VTP client switches sync their database\nto it.

Note that VTP only syncs the VLAN database,\n

on each switch separately, for example SWITCHPORT\n

VTP does not automatically assign interfaces\nto VLANs.

Both of these protocols are no longer on the\n

them and their basic functions, you may get\n

Okay let’s move on to today’s quiz.

As a bonus, I will also feature one practice\n

set of practice exams I highly recommend you\n

Check out ExSim via the link in the video\ndescription.

Okay, let’s go to question 1 of today’s\nquiz.

SW1 and SW2 are connected, are both new switches,\n

However, SW2’s power supply fails so you\n

You reset the configuration before connecting\n

that a trunk is formed between the two switches.

A, interfaces on old switches default to switchport\nmode trunk.

B, interfaces on old switches default to switchport\n

Or C, access ports are a feature of newer\nswitches.

Pause the video to think about your answer.

The answer is B, interfaces on old switches\n

Newer switches default to dynamic auto.

So, in this case SW1’s interface is probably\n

switch’s interface is probably in dynamic\n

SW1 is connected to SW2, and SW2 is connected\nto SW3.

You want SW2 to forward SW1’s VLAN database\n

to synchronize its VLAN database to SW1.

Which command should you use on SW2?

Pause the video to think about your answer.

The answer is a, vtp mode transparent.

A switch in VTP transparent mode will forward\n

VLAN database to the VTP server.

It also won’t advertise its own VLAN database. Let's go to

What are two methods to reset a switch’s\n

Each answer is a complete solution).

A, change the VTP domain to an unused domain\nname.

B, change the switch to VTP server mode.

C, change the switch to VTP transparent mode.

Or D, use the VTP RESET command.

Pause the video to think about your answer.

The answers are A, change the vtp domain to\n

Either of these methods will reset the revision\nnumber to 0.

This is useful if adding a switch with a higher\n

Okay, now let’s go to today’s Boson ExSim\nquestion.

For today's Boson ExSim practice question,\n

So this is about DTP, Dynamic Trunking Protocol.

Select the VLAN trunking operational modes\n

and drag them to the resulting trunking configuration.

So here we have one end of the connection,\none switch interface.

And then the other switch, the other end.

Access, dynamic auto, dynamic desirable, or\ntrunk.

Okay, so see if you can complete this chart\non your own.

Pause the video if you want to try it.

Okay, so let's walk through the answers.

So, here on one end of the connection, access\nmode.

Manually configuring a switch port in access\n

It won't form a trunk port, no matter what.

So, two access ports will result in an operational\n

Access and dynamic auto, same thing.

So, dynamic auto can form a trunk but it won't\n

end is trying to form a trunk.

Although this end is trying to form a trunk,\n

Now, access and trunk that is a misconfig.

Do not do this in a real network.

You can try it out in a lab to see what happens,\n

Dynamic auto and access, well we just saw\nthat here.

Dynamic auto and dynamic auto.

Neither is actively trying to form a trunk,\n

Dynamic auto and dynamic desirable.

This end is actively trying to form a trunk,\n

Same thing, dynamic auto and trunk will form\na trunk.

Even if you manually configure 'switchport\n

end will actively try to form a trunk with\nthe other end.

And since it is dynamic auto, they will form\na trunk.

Okay, dynamic desirable and access, that will\nresult in access.

This end will refuse to become a trunk.

Dynamic desirable and dynamic auto, that will\nform a trunk.

Two dynamic desirables definitely form a trunk.

Okay, next, moving on to trunk on this end.

Trunk and access, again that is a misconfig.

Don't do this in a real network.

Trunk and dynamic auto will form a trunk.

Trunk and dynamic desirable, of course.

And, of course, trunk and trunk also will\nform a trunk.

So once you've finished, click on 'done'.

And then click on 'show answer'.

Now, if you don't want to check the answer\n

question in the practice exam.

But let's see if I got the correct answer.

Okay, here is Boson's explanation, you can\nread it if you want.

And there are also references here.

The official cert guide by Wendell Odom, volume\n

And some additional reading from Cisco.

I will link some reading from Cisco in the\n

And this category shows which category of\n

This is from the 'network access' category.

Okay, so that's today's ExSim practice question.

If you want to get a copy of ExSim for yourself,\n

practice exams, please follow the link in\nthe video description.

There will be supplementary materials for\nthis video.

There will be a review flashcard deck to use\n

Download the deck from the link in the description.

There will also be a packet tracer practice\n

That will be in a separate video.

Before finishing today’s video I want to\n

Thank you to Samil, velvijaykum, C Mohd, Johan,\n

the creators of ExSim, by the way, Sidi, Magrathea,\n

Sorry if I pronounced your name incorrectly,\n

One of you is displaying at Channel failed\n

and I’ll see if YouTube can fix it.

This is the list of JCNP-level members at\n

up recently and your name isn’t on here\n

Please subscribe to the channel, like the\n

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