350-401: Implementing Cisco Enterprise Network Core Technologies (ENCOR) Certification Video Training Course

350-401: Implementing Cisco Enterprise Network Core Technologies (ENCOR) certification video training course by prepaway along with practice test questions and answers, study guide and exam dumps provides the ultimate training package to help you pass.

Infrastructure

1. 3.1 Infrastructure

In Section 3 dot 0, we have infrastructure that, as you can see, weighs 30%, and the topics that we have belong to Layer 2. So here you can see the two layers of important topics. For instance, strength, VLAN, ETA, channel, RHTP, and MSG eleven. We have to learn important protocols like EAGRE, OSPF, and BGP, then wireless, and finally we have IP services. So let's begin with Section 3 and Layer 2, or Book 1. The agenda here is to learn about the wheel and trunk and the various troubleshooting options that we have. So let's start with three, that is, the three dots A belonging to layer two, troubleshooting trunks, etc.

2. Vlan & trunk Part01

Let's just start at three dots, where we have to learn about layer-two technology and a few of the troubleshooting steps. So before starting three dots, one A, I just wanted to quickly review VLAN, trunking, and trunking protocols. So you can see in the diagram that when you have two switches and connect them, you obviously want to allow different wheels inside that. So that's why the distribution layer switch and the access layer switch have eight 2.1-cubic-foot cube trunk. Now, what type of trunks do we have that I'm going to discuss?

So let's first understand what VLAN is and why we need it. What is the default nature of a switch? We know that by default, a switch fires whenever it receives a frame. So, for example, you haven't enabled any type of VLAN or you're not working to create any VLANs on the switch. So whenever the frame comes and hits the switch, it will broadcast that particular frame to all the available interfaces, correct?

And in this way, the number of collision domains or the number of collisions will increase rather than what you can do, which is that whatever switch you have, you can divide that switch into a smaller group, and that smaller group is nothing but the virtual land. So you're dividing this land segment into smaller groups, such as VLAN 10, VLAN 20, and VLAN 30. In that case, when a request comes in, it will only be broadcast to that specific group because they have the logical boundary because they are on a different VLAN. So VLAN is nothing but a logical boundary to reduce the broadcast domain.

Plus, when we create the VLAN by default, we are also providing some more security as well.So VLAN 10 and VLAN 20 will not communicate unless we have a router between them, which we can do with the router-on-a-stick concept or if the switch supports SVI. So they need some sort of gateway to communicate across the VLAN. So here you can see in the diagram that you have VLAN 100 and VLAN 200. They are purely on different IP subnets. So two different IP subnets are two different broadcast domains. They will communicate only if they know how to reach the gateway or if they have to cross the gateway or the boundary. Now, how do I create the VLAN? It's very easy; you can go to the global configuration mode, give the VLAN and the number, and then give the name.

So VLAN number and name can be defined in this manner. You can see that we support all the way up to VLANs, which means you can create up to 4094 VLANs starting from one default, but this range of 1006 to 4094 will be supported in transport mode, which means they will be supported within the extended VLAN range. You can go and create up to 12,000 and 5002, three, four, and five are reserved for token ring and FTDI purposes, respectively. So we can go and create the villains. It's very easy to create. So here I am inside the switch, and what I can do is go and create, say, VLAN 100, and then I can go and give the name, say, "service." Then we can check the VLAN. So here you can see that you have VLAN 1 by default, and all the interfaces are by default part of that VLAN. Then there are the backup VLANs 1002 and 1005. But again, you can go and create the VLAN. So, for example, I have created VLAN 100, which I should exit, and then we can go and check that VLAN.

So you can see that the VLAN 100 has now been created. I will not add any interface, but if you want, we can add the interface as well. So, for example, let's see what available interfaces we have to this particular switch for any of the interfaces in your interface brief. These are the interfaces that I can see here. And if I can check the interfaces and the summary, now you can see that you have these interfaces because this is the virtual switch. So you are seeing a lower number of interfaces. But I can go to any of the interfaces, for example, one plus one, and then I can go to switch port mode access. We'll talk about this mode of access and trunk, and then I'll go assign switchboard access VLAN hundred, and then I'll check on this specific interface, which is showing interface eleven, and we have this VLAN option.

Then we have options for the trunk as well. So this mapping will not work. But if you go and check your interface and then trunk, here you can see that the encapsulation is negotiated. This is not tracking. What is shrinking? What is non-tracking? We'll see that the number of VLANs allowed over this interface is VLAN 100, which we've created, and we'll go check it. So here you have the command, and you can check show VLAN, which just now we have checked. Now, if you want to assign that particular VLAN to the interface, you can go and switch to accessing VLAN handing. Again, you can go and check "show VLAN." So 100 is assigned to this particular interface. Now, what type of ports do we have that we can assign to Vielan? We have access and we have trunk. So what does it mean? It simply means that if you have a switch and that switch is connected to the terminating device, that is where you are terminating the network.

So, for that specific interface, you can specify inside-access VLAN, such as access VLAN 100, 200, 300, and so on. And that's why, in corporate networks, we are creating certain types of VLANs. For example, VLAN name data, VLAN name wires, VLAN name sales, HR, et cetera, et cetera. So when terminating devices generally, we assign them to the access port. But where you want to connect the other networking devices and extend that access VLAN throughout the network, or propagate that VLAN throughout the network, So whenever you're connecting a networking device to another networking device that is not terminating, you want to extend the network. So at that point, you want to create the trunk. So trunk simply means that it can allow multiple access to a VLAN or multiple VLAN access, implying that they are only part of one VLAN. Later on, we'll see that we have different types of trunking protocols.

So here you can see that rather than using three or four different labels over one interface, once you enable the trunk, you can allow different VLANs over that. For example, we have trunking protocols for VLAN 100, 101, and 102, as well as ISL, which is the Cisco proprietary enter switch link. Then there's the industrial standard of 80 2.1 cu ft. Now in this diagram, it is quite clear that if you have terminating devices, then these terminating devices are part of the same VLAN or AVLAN. You can see VLAN 100. Here you can see VLAN 200. Here, you have VLAN 200 like that. And suppose you want to extend or pass multiple VLANs over the trunk link, you can go ahead and allow those VLANs to pass through connecting networking devices, correct? So either we can use L or we can use 802.1Q.

Here we have a dynamic trunking protocol as well, which is something you can think of as dynamically negotiating the trunk or dynamically negotiating to switch properties. Although we have options to do this configuration manually as well, So, in the following slides, I'll show you how we'll do this manual configuration and how we'll do it dynamically. The 80 2.1Q characteristic is now the standard. You can also use 80 2.1 Q, which is lighter than the ISL that encases the entire frame. The feature, or improvement, is that they are embedded. So here you can see that they are embedding a four-byte VLAN tag. So they are adding some tags to the frame. And because they are adding four bytes of frame, the default size of the frame will increase once they add the frame and the tag. And then it supports a maximum of 4096 VLANs.

So, how does it look now? It looks like this. So you have the frame. When you combine a 2.1 Q VLAN tag with an insideVLAN tag, you get a VLAN ID of twelve bits. As a result, it supports 4096 VLANs. because two to the power of twelve If you check this number, you will find it to be 4K. Correct? So two becomes two. If you do it twelve times, we know that you can do the math. So you'll find that it is 4K AP. Apart from that, we have priority with the protocol tag. We have some bits as well. That is the canonical format bit. Okay, so we have just an overhead of four bytes, and it is propagating the number of VLANs through this tab. So let me quickly log into the switch, and I'll create a VLAN 200. Then I have switch one in between two switches, and switch to will enable the trunk. So let's do that.

3. Vlan & trunk Part02

Trunk. And now it is telling me that command C was rejected because the trunk encapsulation is automatic. If you want to do it manually, you must create a switch port trunk relationship, and you can see that there is only one Q ISL to negotiate. So I'll do one Q and then switch and put in more trunk. Okay, and what type of VLAN do you want to allow? VLAN 102 hundred was allowed on the switch port trunk. Although I have not yet created VLAN 102 hundred, I want to create 102 hundred and do not want to add VLAN ten, so I can remove ten. Okay, we can now go to the interface and even zero one. So what command are we using? First and foremost, we are using switchport switchboard trunk encapsulation one Q. That is done manually. I'm telling you that encapsulation is one queue on the switchboard modem trunk, and we are allowing VLAN 102 hundred.I can do the same thing on this side. I can navigate to interface range E 1, and we can now check show interface E zero one trunk. This is one very good command. Here, you can see that the allowed VLAN over E one is this and that the allowed VLAN over a specific interface is this. We can go ahead and double-check sure and interface E zero. So this is the command that we are working on at the moment. I haven't created villain 200 for Otherswitch, so I should create that also. but just for demo purposes. This is the goal. This is the way that we can go and create the VLAN, and then we can create a manual tracking system or we can do manual training as well.

4. DTP Dynamic Trunking Protocol

Next, we have to understand the trunk and the dynamic trunking protocol (DTP).We know that we can create the trunk or pass multiple VLANs across two different switches or an interswitch link. We can build the trunk. We can do it manually if we want. And then we have options that we can do. Or we can use a dynamic protocol as well. So, for example, if you have a type 24 interface and run the command switchboard modetrunk, it will first throw an error. It will inform you that you must first perform the trunk encapsulation protocol. Run the trunk encapsulation protocol, either ISL or Q. So, suppose you have two switches connected back-to-back, say one switch here and another switch here. If I do the ISL interface link here and the tone Q here, they will not form the trunk. As a result, both parties must adhere to the same protocol, or encapsulation.

And then only they will form the trunk. So for example, if I give the same encapsulations, for example, eighteen Q or 8021 Q or one Q, et cetera, Then they will form the trunk. Now we have the option. Either we want to do it manually or we want to use the DTP dynamic trunking protocol. In that case, you can go to one side and engage in encapsulation and negotiation. Switch for trunk or encapsulation negotiate is the full command. They will, however, prefer ISL. They will not prefer 802.1Q due to these other Cisco switches; they are going to prefer ISL better. We can do it manually for as long as possible.

Now, once you have multiple VLANs and you want to allow them, you have the option "switchport trunk allow VLAN." And then you can give a number of VLANs or a range of VLANs. You can also remove something that we already removed in the previous section if you want to. We have allowed certain villains. Now, with this TTP dynamic trunking protocol, the trunk is created dynamically. Again, we have options. As a result, this DTP has two modes for dynamically determining whether a port becomes a tank or not. Dynamic desirable is followed by dynamic auto. So, if I go to a specific interface and type switchport mode, dynamic, and questionmark, I will see it in the switch as well. So I have the choice between dynamically desirable and dynamic auto. Now we have a long list of what mode they are running in and how they will initiate that funk if two different switches are flipped.

So, for example, you can do it manually or automatically with the help of DTP. So, if you make trunks manually, they will obviously form the trunk on one side; the other side is dynamically desirable. Dynamic Desirable means you are sending the package to form the trunk, which means you are sending the negotiating package, but Dynamic Auto will not send. So we'll see that the trunk will be formed by one side trunk and the other side, Dynamic Auto. If you have dynamically desirable neighbours on one side, they will form the trunk. So all these cases are forming the trunk. And suppose that if you have Dynamic Desirable and Dynamic Auto, they will form the trunk. But if you have Dynamic Auto, they will not form the trunk because, at both sites, they will expect that they are ready to listen to the frames, but they are not actively sending the frames. So that's why they will not form the trunk. Assume you want to disable GTP and have two options: switch to no negotiation, correct? So in that case, we are not using this TTP to form the trunk.

And here's the summary slide for whatever we talked about here. Now, what are the troubleshooting options we have? Suppose you are forming a trunk, but this trunk is not coming up. So you should check these things, like what's the trunk mode (ISL versus 80.2.1 Q with respect to frame dragging protocol)? So this is trunk mode, and you should check what the mode of the interface access is—trunk, trunk et cetera. Then the dragging protocol is ISL versus 80 2.1 Q. Then you have a native VLAN mismatch.

Assume that on one side you allow 102 hundred and on the other side you only allow 200. Do you have any VTP domains configured? We'll see that VTP in the upcoming section. And that is only true when you are using DTP to negotiate with that bank. So you should go check these things one by one. Then we have one very important command here. It says "Show interface," "interface name," and "Switchboard" at the bottom. This is actually a very important command included with the Show interface trunk.

So these two commands are there for verification, and you can run both sides, miss both switches, and run this command to see which VLANs are allowed, which protocol is running, what trunk mode is set to, and so on. So let me quickly go and log into the switch, and we can do some of the verification commands. So I am inside the switch, and if you go and check your interface description, we are just checking that switch and switching to see which interfaces they are using. So, one by one, these are the interfaces he's connecting. You switch one and switch two. And if you look in the Showinterface trunk, you'll notice one very important command. So you can see that e is zero and one here. They're allowing these two VLANs, although the management domain shows only 100. Why? Because if you go and check ShowVLAN, you have only one VLAN. So I'll go ahead and create VLAN 200 as well as name it something like clients.

Now, if you go and check, we have a server and we have clients. although we haven't assigned that to any of the interfaces. Now we can go and check the interface trunk. And now, here, you can see these VLANs coming. Okay. All right. You can see it right away now that it is in the status. They have the status of trunking. Native. VLAN number one. The mode is on. Okay, now this is the configuration we are using if I go to another site. Because we haven't created any VLANs, we'll use interface and then trunks 100 and 200. So it is not showing anything. Mode is on encapsulation, either zero or 2.12; that's okay.

Then I can go here. Also, I can create a VLAN 100 name service and then a VLAN 200 name client. Then we can go check showinterface trunk to ensure you get the same result. Now, the next very important thing that we can check is interface e0 and then the switch port. This is actually a nice output that will give you details about VLAN and trunk. So administrative mode is operational. The trunk is encapsulating a zero 2.1 q negotiating mode villain; that's the native VLAN; that's fine; tagging is enabled; voice VLAN is none. We are not using a private VLAN at this point in time. trunk is enabled.

We are passing 100 and 200 prunings, which means there are some default options as well. So, at this point, all we can do is go through all of the DTP options. So if I go to interface zero, you can see what options you have once I'm inside the switch port. So you have a no-negotiate option if you don't want to, or if you want to turn off GDP, you can use non-negotiate. Then, if you want to check mode, you can see auto and undesirable, and we've seen that list. So DDD on one side and DDD on the other side will form the trunk. They will not form the trunk if you have auto, auto on both sides and dynamic auto, dynamicauto, and vice versa. Okay, so this is the way that we can create the trunks, and we can verify them as well. So, let's get this party started.

5. VTP VLAN Trunking Protocol

Next, we have the VTP VLAN ranking protocol. And what is the use of VTP? We'll see if this is something we want to dynamically or automatically replicate or propagate the VLAN. This is also useful for large infrastructures where you don't want to create VLANs switch by switch or hop by hop. So in this case, we can use VDP as a feature that can replicate the VLAN or, in terms of the VLAN database, from one switch to the end switch. Right? So how are we going to do this, what are the terminologies used, and what are we going to discuss and learn about all those things in this particular section? So you have this VDP and this VTP, and they each have their own features. So, what features do they have? For starters, they have versions one and two.

Version two is quite popular, although we also have version three, which has some added advantages. So let's focus on version two, and we'll see what features we have in version three as well. VTP version two with VLAN consistency and domain-independent transparent pass through means you have an advantage over version one.

And we'll see how we can configure it in version two. What are the key components we have? That will be seen in the upcoming slide. Now, what important thing do we have in version three? Version three can not only replicate the Vlad database, but also the other databases, such as the Mist multiple spanning pre-protocol. Apart from that, version three can support up to 4000 VLANs. They are supporting private VLAN, they have improved authentication, and they are addressing whatever issues you have with version two. And in version two, there is a bug that assumes you have switches and accidentally brought a new switch into the BTP domain if the domain names are the same.

And suppose the revision number for that new switch is higher. So whatever database that new switch has, they will go and write those databases, or those will be added to all the switches, and you can understand how big that issue is and how big it will be. So there is no database protection mechanism that we have in version 2 that is there in version 3. As you can see, using VTP primary and secondary serverability to enable VTP on a per port basis protects against accidental database overrides. Okay, what modes do we have for VTP? We have three modes. Actually, we have four modes. Let me show you the diagram here. So you have a server, a client, transparency, and an off-server here.

That means you can create the database, and from there, with the revision number, it will go and write to all the clients, including the client who is listening to and updating their database, as well as the client who is simply passing that information. In a diagram, you can see that you have a server. He's sending the information because this is in transparent mode, and he's passing that on to the other client, who is learning that new information. Likewise, here you can see that the server is sending to the other client if the VTP is off, so they will ignore the VTP update. So on a switch where you don't want that VTP update, you can turn that off so that particular switch will not get the VTP updates correct.

So you've explained the same thing in this diagram, and then you have the notes to refer to. Version one and Version two are available. In version two, we have added advantages and features. One of the very interesting and important things we have with respect to troubleshooting is the revision number. Now in the lab section, we will see this format of the revision number as well. Not only the format, but when you go and check "Show BTP," "Show BTP," you will find that you have the revision numbers. At the moment you will add the VLAN, the revision number will upgrade, and then since he has the higher revision number, he will send the advertisement to the other peers, which are downstream switches, to update the database that you have added inside the server VLAN, right? So that's why the revision number is important because it is one of the components of the VTP advertisement.

So you can see here that if you want to change this revision number, because we don't want to connect any switch by default, any network with a higher revision number, because the switch mode is served by default. As a result, if the revision number is higher, it will begin sending the VDP advertisement, leading others to believe the revision number is higher. So I should overwrite my database as well. So you don't want to do this.

The safe thing is that you change the mode to "transparent" and then change it back to the server or client. So if you make that too transparent, what will happen is that they will change their revision number to zero. and this is particularly true for the new switch. The other option is to change the VTP domain name and then change it back to its original name. So you can change the domain name and change it back. The best option we have is the option to change the mode to transparent.

Okay, now we have already discussed VTP version three. They have this protection mechanism because they have VTP on their primary and secondary servers. What type of messages do we have inside VTP? We have summary advertising, we have subnet advertising, and we have advertisement requests for summary advertising. It is sending the VTPversion domain configuration reviews here, and the time is stump and MDF. Correct? Assume they change their domain name and it is no longer the same. if they are not in the same domain. Obviously, they will not read those databases, and they will not override those databases. And the same is true with the MDF edges as well. They should have a common password so they can replicate the database or understand the database and override it later on.

So Switch is sending the summary advertisement and the subnet advertisement. In both the summary advertisement and the subnet advertisement, you'll find that you have a configuration revision number. So, inside the subject—not the subnet—it is a subset advertisement. Inside the subset advertisement, again, you have the revision number. Revision numbers simply mean that if you are getting some information from a higher revision number, you have to overwrite it. Now suppose you can see that there is one use case for an advertisement request. What this means is that if Switch receives a summary advertisement with a revision number higher than its own, for example, if I receive an update with revision number three but my own is, say, two, Switch will ignore it. So I am lowering the revision number.

Then I will send an advertisement request because my revision number is lower. You write down all of the VLAN details and update my revision number. So all the devices in a network should have the same revision number. Okay? All right. So, how do we go about configuring it? It's very easy. In the domain, you must complete at least two tasks. So you have to go and define the BTP domain. And then in VDP mode, you define the BTP domain. VTP mode even though we have to define the VDP version as well. So you set up VTP domain, VTP mode, and BTP version.

And if you want to do the protection, you can use the VTP password as well. So it's very easy to configure if you follow these configuration steps. So it's easy to do the configuration. How can we be sure? You can go and check your BTP status. The VTP version is two, the configuration division is 42, the maximum VLAN supported is 1,000, and there are seven existing VLANs. The operational mode is server. The domain name is my domain. The pruning mode is visible at this moment. We'll see what it means by "pruning." And this Mt.

Five digestive is also there again, so we can go and check the VTP counters as well. So now here, you can see that we have the VTP pruning. What exactly does "VTP pruning" imply? Pruning simply means that you cut off unnecessary information. That's the prune. Now, VTP pruning means that you don't want to propagate unnecessary information to the switches. As illustrated in the diagram: Assume you change B's information to reveal the identity of the villain.

He will transmit switch CV 200. That switch C isn't going to understand anything. And switch A will advertise VLAN 300. Again, he will not understand because you don't have that. In that case, you can simply cut off this information in order to advertise in the first place. So here you can see that you can go to the global switch globally. You can enable BTP pruning, and once that is done, you can go to the switch interface where this interface link is connected and do switch, trunk, and VLAN pruning. Apart from that, you have other options as well, like VLAN add, remove, etc., etc.

All of these options are available with the standard trunk as well. So we can prune those unnecessary villains that propagate from one place to another. Okay? If you already want to do optimization conversions, we discussed DTP in the previous section. Alright, so this is the VTPPruding, and this is the VTP. If I want to summarise this, how can I understand VTP? So we can consider this: that VTP. You must configure at least two things if you want to configure something. But four things are required, like a VTP domain, a VTP version, a VTP mode, and a password. BTP has version 1232, of which version 3 is the most popular to use.

Their modes are client, server, and transfer, and they simply bypass the advertisement server who is creating clients who are receiving the common factor in all these modes, which are the revision numbers. So if the revision number is higher, he has the authority to update the database on the other devices. Correct? Then we noticed that we had the advertisement as a summary and subject. And if your revision number is less than that, you will send the advertisement request to update that revision number. We will see how we are going to configure it in the next section.

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