Cisco CCIE Enterprise 350-401 Topic: Infrastructure Part 2
December 13, 2022

12. RSTP Lab

Now we have the lapse section. So what we are going to do here is I’m going to run the RSTP in between switches one, two, and three. The correct answers are 10110, 2 and 3. So, as you can see in the diagram, we have the that is connected in this way. Say one, two, and three. So we’ll run the STP here, and then we’ll verify that these are the interfaces from switch one. I’ll figure out to two, then one, two, three, and then two to three with the help of a social neighbor. And then we’ll run that. So what I’m going to do first of all is go and create VLANs on all the switches. So let me quickly go and create the VLAN. For example, VLAN 10, because we know that all the VLANs have their own STP instance. So I can go to this script, and then I can select all. I can go to Config and Vlantis, and then we can ntis, and theSo send this script to all the switches, all right? Now, once we have this and we can go and check “show VLAN,” we have VLAN. Now we can go and check for a spanning tree. And for spanning trees, we have a few very important and interesting commands that we used to apply all the time or that we used to run all the time, like show spanning tree detail and show spanning tree summary.

So here I am, ready to take over the entire show. Here you can see a summary of all these instances. Here you can see that blocking listening, learning, forwarding, etc. Now, we know that by default, we are running STP. So that’s why you’re getting this result. We haven’t enabled Rapid PBS-T. We have to change the mode for that. We’ll do that, and then you have the details. command in detail. Command will teach you most of the basics, such as topology, change notifications, STP timers, and so on. So here you can see that we are actually dealing with switch number one for entry I. I don’t want to add other switches and interfaces, but we have so many interfaces that are coming here, so let me try to run a few more commands, and then we have interface, which is also a very important command, so for example, interface zero and enter. So now, with this command, I can see that this particular interface is in the forwarding state.

The rule is designated, and like that, I can go and check. So basically, say, for example, I have three switches. And in this switch, I want to know: who is my root? Suppose I have switch one and then, for example, switch two and switch three. They are connected like this. So let’s try to figure out, first of all, who is taking the route. Okay, so for that, I can go back to the show, spanning every detail. And we’ll see that here. Who is the route for? Vlantin. I am not considering VLAN zero. So let us leave this VLAN zero wherever we see this villain zero. So please allow me to quickly check that. Do I have VLAN 10 everywhere? So I can see I have a VLAN here, and then I should have a VLAN here. So I have all the VLANs, although I haven’t added any interfaces inside the Vlant ten.So what I will do is move some interfaces inside Villantin. So let’s do that. I’ll show you CDP neighbors. Let’s see who’s connected to switches two and three. So here you can see 0223, and this is also a switch for taxes vladimir.Okay, I’ll go to switch number two. We also run socialDP neighbor-conflict interface range e here.

Let’s see. So we have it linked. So, starting with switch number three, we’ll look for neighbours with numbers one and two. So these are the ports. So I can go ahead and do interface range zero, which is still free, switchport accessville, and ten. All right, because we want to verify this only for VLAN 10. VLAN 10 is followed by detail. So you can see that this is now telling you information about Villantin. That’s okay. And if I go inside villain number ten, and check who the root is, So here you can see that the root portID is the priority in the Mac address. So let’s verify that this Mac address belongs to this particular switch, correct? So now, if you go ahead and check your Mac address, it is AABC. Now, if you see this particular output, what is the priority? 32778. Why? This is seven, seven, eight because 32768 is the default priority plus the villain ID. So that’s why it’s showing like this. So everywhere you look, you will find that the priority is 32778. As a result, whoever has the lowest Mac address will become the correct root page. All right. So let’s continue this. All right, so we can verify like this because we have two interfaces connected. As a result, you’re seeing interface e zero-slash-zero through zero-slash-three. Although if you go to any of the ports, you’ll see the details, which you can see clearly. For example, e two, v four, and vlantz are the designated forwarding; that is, the DP, the cost of which is the port priority of which is the identifier.

You can see here that they have a priority of 32768 plus ten. That’s the villain’s number, and this is the address. Now the designated bridge has priority. This is the Mac address. Then again, you can see the port priority and all that. The question here is: in this scenario, who is the root, and then who is the nonroot, or maybe who is the root? And then what about the designated port and the root port, blocking, et cetera? We are running this spanning tree protocol at the moment. So for that, you can go and check your spanning tree and then determine what a bridge means yourself. So we have two options here. One is the bridge option; that is one, and then what about the route? So I can go and check the bridge address and then the root address. And here you can see that the bridge address for the villain, on which we’re focusing, and the root address for the villain are both the same. So that means that this particular switch is the route. Now that I know the route, I’d like to know what the port status is. So now if you go ahead and check, say, VLAN 10, and say we have options for interfaces as well as interface-wise, we can go and check E 0, and then I can check the state as well as the detail as well. You can also filter by interface; for example, 0 is the designated port.

So, if you look at the topology diagram, you’ll notice that we have different ports from the switch that will switch one to two, say, and here you also have one. So this is DP. That means if you go and check here, this must be RP, right? Again, in any case, we have a study and are doing the same thing. So now if I go and copy this command here, you can see here that this is root forwarding; that’s correct. So with DP and RP like that, we can go and analyze. Now we need to know the root address and the bridge address. So the root address is what we know it will be. Now again, if you go and check the bridge address for this particular switch, what is the Mac address because priority is the same? Likewise, if you go and check the Mac address for this particular switch, you’ll find it is 6700.

So as for the lower Macaddress, which one is the winner? If you examine this specific interface, such as the interface between switches two and three here, you will notice this blocking. So, for example, spanning three VLANs in detail Now, for VLAN 10, you’ll notice that only a few of the ports are present. So this is the path. It’s fine; you’ll find blocking, blocking, and ports here in switch three; a few of the ports are in the blocking stage. Okay, so this is related to all these commands related to STP. So what are the big commands we have or important commands we have for showing spanning tree summaries? It will give you the summary spanning tree, and for that particular VLAN, you can check the detail like this: The spanning tree can then be examined. So, for example, sometimes we used filters as well. So, for example, I can check Include, and then we can filter specific things here, such as “designated,” and then I can add “designated” here and say, for example, that other things are also designated forwarding if I have them, because this is the route. So here you can see all the ports. They are coming like this. We have options; we can filter, and we can add multiple filters as well. You can see that you only have two ports testing it, which is fine, but what we need to do in this lab is run the RSVP. So I’ll go to the switch, and we’ll have to change the mode.

So this is spanning tree mode, and if I type a cushion mark here, you’ll see that you also have MST, PBST, and Rapid PBST modes. Now if you are changing the mode to RapidPBST, you should do this to all the  is go and run thSo we’ll go ahead and paste that command to all the switches, and then the switches will get converged. When the switch is converged, we can go ahead and check “show a spanning query,” and you have the same options here, correct? So you can see here that for MSD, you have another option but show a spanning tree, and then we can go and check detail inside detail, and you can see that VLANOne is selected. I don’t want to check VLAN 1, but still, VLAN 1 is executing an RSTP-compatible spanning-tree protocol. You can double-check this. I can go and run “command show spanning free VLAN ten” and then “detail” so we can check only VLAN ten commands. You will now notice that the port rule has been modified. So DP will be DP. That is not an issue in switch number one.

But if you go and check these switches, numbers two and three, as per the rapid STP, the designation will get changed. So this is root; it’s okay. Designated forwarding, designated forwarding, designated forwarding. Here you can see this alternate blocking. So now you can see that the designations are changing and that the role of the port is getting changed. So VLAN 10, spanning Preland 10 and detail This is the alternate blocking for forwarding, as you can see. Alternate blocking. So this is the way that we can go and run the RSTP, and then we can verify that.

All right, so we can verify like this. If you want to look at more options, go to Share spanning Persistence and Ten. If you want to check the route, then consider other options. Here you can see that you have options related to priority, port, hello, interval details, cost, etcetera, etcetera. Then if you want to check some other stuff, here you can see if I go to the spanning tree again if I want to check the bridge, then the protocol, and if I press Enter. So here you can see it running in RY, the same thing that we have in STP. There’s no slight change in the configuration, but the verification options are the same for STP as they are for RSTP as well.

13. MST Multiple Spanning Tree theory

We have 32 bits of configuration name, 16 bits of revision number, and then we should do VLDB to instance mapping. Now that you can see all of these things in the configuration and labels, you can learn more about all of these terms and terminologies. Now here you can see that important information: if two switches are configured with different mist parameters, they belong to different mist regions. We can have up to 16 MST instances, from zero up to 15. What would happen if I just started Mist? Everything will obviously be wrong inside MST zero, so if you do nothing but enable the MST, they will fall under the MST zero we have. This internal spanning tree is in charge of preserving the topology of the entire reason and all MSTs. Only the IST can send and receive BPD and encapsulate the Mist information within the BPD in an MSP record or M record. The IST is always mapped to instance 0. As a result, we have an internal expansion fund as well. Who is going to map or manage all the records inside the MST? As you’ll see in the entire misty reasoning at an STP or RSTP switch, zero MSG is compatible with other STP implementations, and MSG is obsolete from non-MSG switches. So it’s not that simple. Once you have multiple villains,

For example, I have villains ten through thirty, spanning the years 2021 to 2023. I can map with MSD instances 1, 2, and so on. But still, they are compatible or backup compatible with other MSTs as well. And those particulars will surprise you. It’s similar to having MSDP and then not having MSTP. They are compatible. So, how are we going to configure? First of all, we need to change the mode, and then we have to go inside this fanatic configuration. We can give it the name “revision,” and then we have the instance for “VLAN mapping,” and that’s it. We can go check the pending once we’ve completed the instance-to-VLAN mapping.

And earlier I told you that the way that we are configuring the STP, like how you’re creating the primary or secondary router, etcetera, Similarly, we must do the same things in Mist. OK, so the commands are much simpler. Instead of VLAN instances, they will be the group of VLANs or the instance mapping. So, inside MSD, we map multiple VLANs to a single instance rather than running the commands over VLAN. That is the default nature of traditional or STP 2. We are running the command with respect to the instance. Now, where this instance is pointing, it is pointing towards the group of VLANs, right? So this is the way that we can utilise the resources efficiently. If we have the VLAN, we can group those VLANs, map them to the various instances of Mist, and then, behind the scenes, Ms will work with those groups to improve the overall performance of the switch, such as resource utilisation and CPU capacity, memory, and so on. All right, so let’s stop here, and the next session will perform the lab task.

14. MST Multiple Spanning Tree Lab

Let us perform the LAPT task related to MSD. So, first and foremost, I’ll go in and create, say, VLANs 10 to 100 because we’re going to map these VLANs within misty instances, so I’ll do the same in all the switches. Now we have VLAN 100, and we can go and verify this VLAN. I can see that you have these many VLANs that I can map inside the MSD instance. So, what is the first command I should use to change the spanning pre mode? So now this planning mode is MST, and I should do this with all three switches that we have. So let me go to the configuration mode and configure and copy-paste this mode command again. I’ll go to conft and do the copy-paste.

Now what we can do is go into the spanning tree and MSP configuration modes. Once you’re here, you can see what options you have, and we’ll start by looking for the name revision instance. Then we have this instance, so instance and VLAN for example instance one, and then the VLAN range is from, say, ten to fifty, then we have instance two, VLAN51, 200, that we have created, and we can go and check the configuration with your pending. So here you can see that you have a VLAN instance, and whatever VLAN that we haven’t mapped here, you can see that they are mapped with MSD 0, correct? So now we have two instances like this.

Once we have this, I can exit and we can run the normal spanning pre command, which will show us the spanning premises fee, and then we can check the configuration and go over the details. So, instead of MSP, we can assume you’re using spanning to VLAN. So instead of VLAN, you think of MSG. That’s the command, so we don’t need to memorise anything. So you can see this in detail, as well as the port ID priority and everything else. Now, a different type of vLance is mapped with the MSD instance, which is why it looks like this. Likewise, I can go and run this command on other switches as well, so I should go and change the mode to MSD. Then we should enter configuration mode and run these commands, so let’s do it and verify with truepending, and then we should do this hereto pending, and then we can exit and exit. We can now go check your spanning P Ms fee, and if you want to check the details, we have a retail option, and if you want to check any of the interfaces, we can do that as well.

So MSG instance list say for example if I give word let’s verify this so what word I have here you can see that show spanning DMST you can see the output in detail and this is the name and if I go here and check the output show spanning tree ms tree this is not supported here so if I give say for example number like MST one not like thatbut we can go and give the instance list that we have created that we can actually verify in the configuration This is the way that we can go and map the VLAN to the instance mapping, and then we can go and verify the commands as well.

Now, if you want to change the priority, because switch three has the highest match added, so it’s priority is lowest in terms of selecting the root bridge, so the root is switch number one because his Mac address is the lowest, but if you want to change it, you can go and change spanning three Ms three, and then you can go and check the configuration so we can do like this: If you want to change the priority we have, for example, VLAN 10, you can see the priorities there. This method is for the STP, but we’re focusing on the MST here, and then the instance, say one, and here we have the priority. So we have two options: either we can use the priority command or the root command.

I just wanted to make this switch a root, and we can go and give him root primary, and now if we go and verify the MST command, here you will see who is the bridge and who is the route they switch for MSD one. So now this prior automatically gets decremented, and now that switch three is the route, you can see their port status is changing. Initially, it was forward blocking, but now everything will become forwarding because now my switch number three is the root switch. Okay? And the same rule applies to STP, STPE (where I have to give the wheel), and MSG. You have to provide the instance ID. Alright, so let’s just stop here.

15. 3.2 OSPF Basics

Now we reach 3232, which belongs to layer three technology. In layer three specifically, we have to learn about routing protocols such as OSPF, EIGRP, and BGP, so let’s just start with OSPF. OSPF, an open source link-state protocol, is similar to ISIS. Now, instead of sending the entire topology table hop by hop, link state protocol sends the state of a link to the neighbor device. Now tell me how this technology works, and I’ll try to draw it. So generally, all the links to the protocol are formed first of all in the neighbor table. So they are sending the update to all the adjacent devices, or neighbors, and with the help of neighbor table, they are forming the topology table. Sometimes we refer to the entire database as well, and finally, they ran the SPF algorithm; here, from the topology table, they are going to form the best path, which is the routing table. So we have three different types of tables: the neighbour table or database table, the topology table, and finally the routing table. Now, the mechanism and theory behind this will be seen in subsequent slides, so OSPF is entirely dependent on areas.

Generally, we say that we have one backbone area, so here you can see that you have area zero, and logically all the areas are connected with area zero. Now that these areas are 32 bits, they can be a hash number or defined in an ordered representation, such as this area has a continued area. You can see that you have area zero and then areas one, two, and three, so you might think that they can’t connect area three with areas five or four. Yes, we can make that connection, but as you can see, area four is not directly connected with area zero, so somehow I have to create a tunnel, or for area 3, I have to create area 3 as a tunnel, or we have to use some sort of virtual link. As a result, area four may believe that it is directly connected to area zero. So we need to make such an arrangement. And then the link-state advertisement will flow from one place to other place.That’s why the LSA will correct the OSPF and LSA when there is a change to one of its links and will only send the changes in the update. LLCs are additionally refreshed every 30 minutes. How can we summarise it? By saying that OSP is a linked rate that we call dependence upon area? They are sending their LLCs or their advertisements to all their neighbors. And with that, they are forming the neighbour table under the policy table. And finally, the routing table. Apart from that, The OSPF. Traffic is multicast. They have 2240 for all routers and 2240 for the designated router. The theory behind this can be discussed in an upcoming session. They are using the Dijkstra staff first algorithm to build the routing table from the topology table, and they are supporting the variable-length subnet mask. So here you can see that first of all they form the neighbour table, then they form the database, and then they do their algorithm. That’s the SPF algorithm text. SPF algorithm? Finally, they will form the best table, which is the routing table. OSPF supports IP routing. Their added value is 10; their metric is cost.

They are going to form the neighbour table for the policy table and the routing table. The backbone should be assumed to connect the entire area. That’s area zero. If you have a non-backbone area connected to any other area, then you have to create a tunnel or virtual link in between those two areas. Now, suppose we have this type of triple G. You can see that I have area zero connected to areas one and two. So now what we are going to tell you about these devices is that they are routers A and C. Border routers are what they are called. They are termed “border routers” because they are on the border of different areas. Okay? And we’ll see that the routes are also reflected as a result of that. So when we are talking about the routes, you’ll find that you have O routes and then OIA, which is the Ospfra area. So you have two routes: the intraarea route’s OSP and this one. Then there’s the interior throughout the space, which is this. And we’ll see that we have E1 and E2 routes as well. That is coming from the outside as well. Now, if you look at this diagram, you’ll notice that it’s actually quite simple and straightforward; we have two or three routers in this area. But suppose you have 50 or 100 routers in the area, and suppose I have 200 routers, all of which are within area 0. So at that time, what will happen? The competition entails running that SPF algorithm in such a way that it becomes CPU intensive, as opposed to having a small area with 50 devices, 100 devices, and 50 devices in those areas.

So in that case, all the areas will learn their independent SPF algorithm, and then they will send updates to the backbone. So in that case, the way that we are going to run the SPF algorithm, or in other words, process the CPU utilization, the memory will be optimised and will be used better. Because now you’re running the SPF algorithm across small areas, and then those areas are going to send their LS to the core or to the other areas. Correct? So that’s the thing. That is why we do not have a single logical area but rather several. And then we are going to divide the devices or the routers inside the area. Then here, you can see that. Assume you have a device that is not connected to area zero in this case; in that case, you must create the virtual link, the device that separates the area. They are known as AVR. Then you have an internal router, and then you have a backbone router. These are just the conclusions of terminal logic. All right. Now you can see that there is a possibility that you are connected using a non-OSPF protocol. So you are getting the route, for example, from the EIGRP domain. So in that case, that router is known as a BR autonomous system border router. So now here we can see that Cand. D. is an ABR area border router. However, router G is acting as VR because the route is now coming from the other routing domain to the OSPF. Okay? So here you can see that if you have any other routing domain, that will be treated as a separate autonomous system, and then you have to do the redistribution.

Obviously, the router G will do the redistribution from EIGRP to OSPF when it is coming to OSPF and from OSPF to EIGRP when you are sending your update to the EIGRP domain. In that case, there are two types of areas. Now, what is even an “e two?As you can see, by default, it will be OSPFexternal area type 2, or E 2. So include only the external cost to the destination network. External cost is the metric. Being metric is advertised outside the OSPA domain. This is the default type. Then you have E, which will also have the material; that is the cost. But this will be edited, meaning it will add the cost per hop per router. Include both the external cost and the internal cost. That’s why you have the external cost plus the internal cost to reach the ASR and determine the total metric. However, because E2 only has an external cost, this will remain constant. So in summary, you can see that you have internal routers and that all router interfaces belong to only one area. You have ABR, you have ASBR, and you have a backbone router that is inside area zero. Okay, so this is the baseline summary for the OSPA routing protocol. In the upcoming sessions, we will learn more about OSPF terminologies, and we will have to perform the lab as well.

16. OSPF LSA Types

So what type of LSS do we have in OSPF? OSPF has a long list of LSSs. We are going to discuss the top five, at least, because we are going to use them more and more in the course. So we have LSA. Here you can see types one and two. Now these type 1 and type 2 LSAs reside within the area. They are very much area-specific LSAs. Then we have types three and four generated by the ABR area border router. They can flow from one area to another, as we’ll see in the upcoming slide. And then we have Type 5 LLC. This is generated by an autonomous system border router, indicating that the protocol is not OSPF. They are going to generate that. Here you can see a detailed explanation of all the LSAs. Type one is LSA, and type two is as well. They are within the area. The use of type 1 LSA is that they have the link—obviously the status and the cost of all those links—and they are generated by all the routers in a network. So you can think that type 1 has a default LSA generated by all the routers within that area. Then there are type 2 LSAs produced by Dr in the OSPF network or domain. Again, this is specific to the area when we have the broadcast type of network; obviously, the Dr VDR will come into play at that time. Then we have the network summary LSA. That is type three. Its purpose is to generate data that can be used for interarea communication. You see that all the places you have this interior link So you have areas connected by different areas. And all of the AVRs shown in the diagram will generate type 3 LSAs to facilitate interarea communication. Then we have ASP or something. Now the next question here is: suppose that from interarea you have to reach a non-OSPF domain? So for that reason, we have an autonomous system or router summary. LSA means somehow you need to reach or somehow we have a route to reach the non-OSB protocol. Then we have external LSA type 5. The ASR is now generating this information, which will flood all areas. So all the areas have obviously undergone redistribution. All the areas should know how to reach the autonomous system border router, or the network behind the ASPR. We have type six as well. That is the multicast ASP of type 7 as well. That’s not a stubby area, and this type of seven is actually very important, as we’ll see later. In the diagram, you can see that you have area one, area zero, and area two. So you have this router that belongs to area one, area two, and area zero, and the network LSA is type one, and type two LSA will be generated in that. Then you can see that routers C and D are ABR.

So they are going to generate types three and four. And the router G, which belongs to ASPRhe, is going to generate type 5 LSA. Okay, great. Then how is this OSPF going to form the OSPF neighbour relationship? So if you go and connect to OSPF with two routers in between, suppose for sake of simplicity that I have only two routers connected in a network. So in that case, what will happen? Suppose I have router one and router two, and these two routers are connected, or they are inside area zero. So obviously, these routers, because they are within the area, will send and receive the LSA from the router LSA, correct.So, what happens when they send their greeting packet? Hello packet in a point-to-point or broadcast network; the hello timer is ten seconds, and the dead timer is 42 seconds. So it’s one into four. And in the broadcast network, actually in the NBME network, that will be 30 seconds, and then the day timer will be 34, which is 120 seconds. So they will send and receive. They will exchange their hello packets, and if they are matching certain criteria while sending and receiving the hello packets, then they are going to form a neighbour relationship. So here you can see: what are the things inside the hello packet? What are the fields inside the hello packet? Area ID, area type, prefix, subnet mask, hello interval, deadinterval network type, and authentication are all included. Basically, it is said that they have eight fields inside the hello packet, and you should match at least the area ID, the subnetmask, hello and dead interval authentication, etc. So some fields are mandatory and should match between two routers to form the name of the relationship.

Okay, so here you can see that a labour table is constructed from the Ospflo package, which includes the following: the router ID, the current state, directly connected interfaces, and the IP address of the remote interface of each neighbor. We’ll see that in the lab section, and we’ll go and run the command show IPOSPF neighbor, and then we can see the specifics about the neighbors. Now, the next topic here is the OSPF-designated router and backup-designated router. So what is happening and how are they going to form the Dr. VDR? Or how are they doing the selection for the Dr. video? Let’s discuss that. So here you can see in the diagram that, first of all, these devices should have their priorities. So let me show you what I tried to tell her. I should have slides for that. So here you can see that these devices have their own unique identification. That’s the router ID for all the routers in the network. They have the router ID. We can configure it manually. Consider a device that has a loop back interface or physical interfaces. First of all, they will check the loopback interface if you’re not doing it manually. So that loopback interface will become the router ID, or the highest physical interface will become the router ID. So they should have the router ID that will be set by default if you’re not doing it manually. Once they have the router ID, they will perform the Dr VDR selection, which will only occur in the broadcast network. As shown in the diagram, if router ABC is connected to a shared network or the broadcast network, they will go and select the Dr. and BDR. What will be the selection criteria in this case? The selection criteria are determined by the router’s priority, which is set per interface. The router with the highest priority becomes the Dr, the second highest will become the BDR, and the rest are Dr dwellers, something like Dr BDR LS.

Okay? Now if there is a change in the priority, whichever router has the highest router ID will become the Dr. Now we can go and set this priority like this. We can also go to the interface and set IPSP’s priority, and then force a specific device to be a Dr or VDR. Now, by default, the priority will be one. So obviously the selection will happen with respect to router ID. So whoever has the highest router ID in the network will become Dr. BDR, etcetera. Like that. Assume, for example, that you do not want specific routers or devices to participate in the Dr. bid or selection. So you can go to the interface and set the priority to zero. So if you set the priority to 0, the device will not take part in the VDR. Okay, so what are the important things we have studied in this video? that type of LSA. Then how are they going to form the OSPF neighbour relationship? What are the important fields you have inside the “hello” package? All the devices are sending hello packets to the peer devices or neighbour devices to form the neighbour relationship. Then how are they going to form the DrvD selection? Again, the router ID will be an important factor here. And as for the router ID, they are going to form the drvdr because, by default, we are not setting the price. By default, the priority will be 1, and according to the router, IDP will select who is the deal and who is the BDR.

17. OSPF DR BDR & Lab

Okay, so let me quickly go over what I needed. lyequired.So e one plus twobe a switchboard;switchboard, it should port. So I’ll disable the switch port and then assign the IP address. So, ten 1101 and I’ll generate one loop-zero IP address, 101-0110 1. So what I’ve done here is check and briefly show the IP interface. So I’ve assigned IP addresses to the last two interfaces and one of the loopback interfaces. P addresseright,ygreat. So now we can go to R1 and R2, as well as the interfaces shown here. So I’ll start with R1 and then move on to interface E0. I’ll assign IP 10-1 and then ping to see if the switch for the endswitch is reachable or not. s reachable.Then I’ll go andloopback,one lzero,aand ansay address. I’ll give that loop back one. t loop back.Gthe “d check the show Ibrief”erfayou canef so youcan see that we have the IPthere. gured there.Le2, go to R two a2,inside R two we have interfacezero I can go and give the IP like this, and then I’ll create one loop zero where I can give the IP related to the diagram or as per our schema, and then let me try to ping first of all within the same network. Obviously, everything is inside the same network for this example. So what I’m doing is pinging all of the devices on R 2. So we now have the baseline IP connected to this connectivity. The thing here is that we are going to enable OSPF for all these devices, and we are assuming that all these devices are inside area zero. Correct? So let’s do this. Let me go back to the lab before doing that. At least one of the devices I want to enable the debugging of requires that I enable the debugging of OSPF packets and events, and then I want to enable the debugging of events as well. Okay, let’s do this OSPF configuration so we can get to router OSPF, and then you have to define the process ID, say the one I’m giving at this point in time, and then I should go and advertise the network. So network is, I have two networks, one of which is 10 and the other of which is 10. I can go and put the wild card bit inside area zero.

This is the format in which we can go and enable the OSPF, and you can see that we have events because we have also enabled the debug. You can see that this route is using this multi-car address, and the router ID is selected as one one one.We have discussed this earlier. If I go and check Show IPOs PF, you can see the red router ID is one, one, and we have the other information as well. Okay, so we have the OSPF configuration, and periodically he’s sending the hello packet. We can go ahead and double-check the configuration for what we’ve done. So we have enabled the OSPF process, and then we have advertised the network, correct? So likewise, I can go here and initiate the OSPF process here as well. Then I can go ahead and manually assign the routerID using the CLI command. But if you do not do this automatically, they will take the loopback, the highest loopback, as a router ID. So then I have network ten (110-0255), area zero, and then I have network 2222. Okay, and let’s take a look at what I’ve done here. They are now attempting to exchange this neighbour relationship. From there, they will go and form the topology table, and finally, they will go and form the routing table as well. Okay, so let me quickly see what command I have given here for the network because we have used Slats’ attitude. That’s why I have given. You will now notice that you are loading at the maximum rate. And here, if we can see that information in the log message, we have enabled debugging and OSPF authentication is set to zero.

We haven’t put any authentication in place. So it is telling that OSPF authentication is zero. And you can see here that we have a loading to full message. If you go ahead and check “Show IPOs PF Neighbor,” you’ll notice that you’ve already selected BDR, as router one indicates that router two is BDR. You can tell who the Dr. is if you go to router two and check show IP OSPF neighbor. So for router two, this 1111 is a Dr. What is the interface? What is the IP address that we discussed earlier? Now I’ll go to switch number one. And I’ll go ahead and replace this router with a PFC one as well. And then I will put the network, for example, at the loopback address that we have: 1011-011-0100, area zero. And then I’ll put the network that we want to form the OSPF relationship on. So we have a network. And with the wildcard bit All right, and within area zero at the moment, I’ll do this. I can go and check my IP OSPF neighbor, and you can see that he is seeing who is the Dr and who is the PDR, the third device. Now, if you check the OSPof neighbor, you can clearly see the Dr. other. As a result, this IP address is no longer functional. We haven’t assigned the router ID manually, but you can see that they can detect. It means the router process can go and assign what will be the router IP or router ID for these devices. We can go and check like this, and you can see the ID. If you want to filter and use what I tried to do with this command, simply check the ID, which will tell you who the authority is. Alright, so this is the way that they are going to form the Dr and BDR, and if I have one more device in the Dr, then you could find that the process will stick at two. Okay? So what I’m saying here is that if I’m here and I have one more device connected to this guy here that is also working as a VR, other than these two devices, they will be stuck at a two-base rate. They will not extend the entire topology and database tables, etc. All right, so let’s just stop here.

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