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Cisco CCNA certification proves your professional worth. It tells prospective employers that you can handle the day-to-day work of running a mid- to large-sized Cisco network....
Cisco CCNA certification proves your professional worth. It tells prospective employers that you can handle the day-to-day work of running a mid- to large-sized Cisco network.

The two-exam CCNA process covers lots of innovative features, which better reflect the skills and knowledge you'll need on the job. Passing both exams is your first step towards higher-level Cisco certification, and trainer Jeremy Cioara has mapped these CCNA training videos to the 640-816 test. This CCNA training is not to be missed.

Here's how one user described Jeremy's training: "By the way, Jeremy Cioara has to be by far one of the BEST Cisco trainers I have ever had the privilege to learn from overall. He not only keeps your attention but his energy is contagious and he provides the information at a level where you grasp it rather easily."

The last day to take the 640-816 exam is Sept. 30, 2013. After that date, the only ICND2 exam available will be 200-101. CBT Nuggets has a training course for the 200-101 exam here.

All trademarks and copyrights are the property of their respective holders.
1. Review: Rebuilding the Small Office Network, Part 1 (33 min)
2. Review: Rebuilding the Small Office Network, Part 2 (28 min)
3. Review: Rebuilding the Small Office Network, Part 3 (23 min)
4. Switch VLANs: Understanding VLANs (16 min)
5. Switch VLANs: Understanding Trunks and VTP (39 min)
6. Switch VLANs: Configuring VLANs and VTP, Part 1 (35 min)
7. Switch VLANs: Configuring VLANs and VTP, Part 2 (39 min)
8. Switch STP: Understanding the Spanning-Tree Protocol (28 min)
9. Switch STP: Configuring Basic STP (21 min)
10. Switch STP: Enhancements to STP (29 min)
11. General Switching: Troubleshooting and Security Best Practices (29 min)
12. Subnetting: Understanding VLSM (18 min)
13. Routing Protocols: Distance Vector vs. Link State (26 min)
14. Routing Protocols: OSPF Concepts (30 min)
15. Routing Protocols: OSPF Configuration and Troubleshooting (39 min)
16. Routing Protocols: EIGRP Concepts and Configuration (32 min)
17. Access-Lists: The Rules of the ACL (27 min)
18. Access-Lists: Configuring ACLs (34 min)
19. Access-Lists: Configuring ACLs, Part 2 (48 min)
20. NAT: Understanding the Three Styles of NAT (20 min)
21. NAT: Command-line NAT Configuration (35 min)
22. WAN Connections: Concepts of VPN Technology (33 min)
23. WAN Connections: Implementing PPP Authentication (34 min)
24. WAN Connections: Understanding Frame Relay (28 min)
25. WAN Connections: Configuring Frame Relay (30 min)
26. IPv6: Understanding Basic Concepts and Addressing (34 min)
27. IPv6: Configuring, Routing, and Interoperating (23 min)
28. Certification: Some Last Words for Test Takers (13 min)
29. Advanced TCP/IP: Working with Binary (25 min)
30. Advanced TCP/IP: IP Subnetting, Part 1 (55 min)
31. Advanced TCP/IP: IP Subnetting, Part 2 (22 min)
32. Advanced TCP/IP: IP Subnetting, Part 3 (19 min)

Review: Rebuilding the Small Office Network, Part 1

Review: Rebuilding the Small Office Network, Part 2

Review: Rebuilding the Small Office Network, Part 3

Switch VLANs: Understanding VLANs

Switch VLANs: Understanding Trunks and VTP

Switch VLANs: Configuring VLANs and VTP, Part 1

Switch VLANs: Configuring VLANs and VTP, Part 2

Switch STP: Understanding the Spanning-Tree Protocol

Switch STP: Configuring Basic STP

Switch STP: Enhancements to STP

General Switching: Troubleshooting and Security Best Practices

Subnetting: Understanding VLSM

Routing Protocols: Distance Vector vs. Link State

Routing Protocols: OSPF Concepts

00:00:00

What better protocol to introduce first in this ICD 2 series than OSPF. And I say that only because OSPF is the most popular routing protocol in the world. OSPF is awesome in the sense that it is one of those protocols that just has so much complexity that as you move on into the CCNP track, dozens of videos will be dedicated just to this protocol and all of its concepts. But, it has been moved and introduced

00:00:30

into the CCNA criteria because even in all its complexity it is the most popular routing protocol in the world. And by the time you're done here you will have a very good understanding of what it is and how to work with it. The CCNP will just build on that. It is kind of like you're.. You're walking up the mountain of

00:00:47

OSPF and you'll get about halfway up in the CCNA level and CCNP just takes you to the peak of the mountain to where you know everything. So, in this video we're going to talk about, first and foremost, route summarization. The rest of OSPF won't make much sense without understanding route summarization.

00:01:06

We'll then move into the OSPF terms and network design. Half of the battle in OSPF is understanding what these different terms mean, and why we design our network certain ways. We'll talk about that. Finally, we'll look at the OSPF 'hello packet,' which is the foundation piece of OSPF that allows routers to form neighbor relationships with each other and exchange routes.

00:01:31

Many of the concepts that we talked about in OSPF will not make too much sense without understanding the idea of route summarization. Route summarization is all about making routing tables smaller. Here's the fact - the larger your routing table the more inefficient your router becomes. Your router is slower.

00:01:51

And the reason why is because the router has more information to weed through for every single packet. It receives a packet and it's like ok, you're going to here, let me look at this routing table that's just massive now this, now this, it looks down through that whole routing table to try and find the best route. So what we can do to make our routers

00:02:08

more efficient is to shrink the routing table. Summarization is how that's possible. Here is the idea. Let's say we have two routers in our organization. Well, let's say many routers but two in this picture. Router 1 over on the left and router 2 over here on the right. Now router 1 has a connection somehow to all these 192.168.x networks. We got 001020, all the way dah dah dah dah all the way down to 15.0. Now with every routing protocol router 1 is gonna send those routes over to router 2. That's what routing protocols do. So router 2 will now have all these routes in its routing table and it will say I can reach them, and that's how we know routing. That's how routing protocols

00:02:50

educate each other. But, here's the problem with that. Router 2 now has 16 routes, 0 through 15, sitting in its routing table. That it.. Number 1 goes all the same direction to reach. There's only one way to get to router 1 and all of those separate routes, so, you know that's..that's the first..first issue.

00:03:11

issue. The second issue is, if one of these networks go down, then that needs to be updated and replicated to router 2 and router 2 is gonna have to replicate that to other routers in the corporate network because they all have the same routes, and they all need to have a synchronized routing table. Now, honestly, when you will when

00:03:28

we look at this picture does router 2 really need to know that the 1.0 network went down? Now, initially my thoughts go to well, yes it needs to, because maybe it has traffic that's going to that. Well, if router 1 knows that it's down router 2 will send a packet, the very first packet to router 1, and router 1 will then just reply and say ICNP unreachable. You can't get there from here. So, router 1 will take care of any packets that are going to that network, because it knows that it's down, so in the big picture, it really doesn't make too much sense for router 2 to know the specifics about those networks. So here's what we can do.

00:04:09

Route summarization is the process of summing up all these routes into fewer advertisements. I'll give you what I will call cheap summarization. Here's an example. I can go on router 1, and I could say, I am going to advertise 192.168.0.0/16 Meaning, I've pulled this subnet mask back to be a class B subnet mask.

00:04:37

So, here's what in essence router 1 is saying, it's saying router 2 I know about every single network that starts with 192.168. Router 2 puts that in it's routing tables and says, wow, that's a huge router over there. It's got all of my 192.168 networks. Now it only really has these 16 of them, but it's advertising the whole scope. Now when you do that, the routing protocol will automatically suppress all the more specific routes. So there's no need to go and send 192.168.0.0/24 or 1.0 or 2.0 or 3 because all of those are encompassed in 192.168.0.0/16 It's the one big advertisement.

00:05:19

Now that's.. that's like I said what I call cheap summarization, because it's not very efficient. Meaning, if I send that route advertisement, that means that this router, router 1, claims to have all 192.168 networks and I can no longer use 192.168 networks anywhere else my network because router 1 has laid claim to them all. It..it says that I have them you cannot use them. So, it only has 16 networks but it claims to have them all, and we've now wasted a whole chunk of IP addresses that could be of use to us. So here's how you can do

00:05:57

router summarization more efficiently. We need to get back to working in binary, and working in our subnetting mindset. Here's the idea. I've got all of these works. They all start with 192. They all start with 168. Now, we see the difference in the third octet. Let's break that into binary. 192.168.0 is one, two, five, six, seven eight zeros, then all zeros over here, right? 192.168.1 is 00000001 dot, and all zeros over here. Two, I'll just kinda, parenthesis here, is all zeros 1 zero. Three, is all zeros 1-1. Four is all zeros 1-0-0. Now we're all thinking in binary. And the, and the same trend goes down you know

00:06:43

da..da..da..da..da. Let me get to, ah, I'm running out of space here. So, ah, let me, let me go to we'll say 13. Thirteen in binary is 128-64-32-16-8- 4-2-1, that's thirteen. Fourteen is 1110; Fifteen 1111. So, looking at all this, I know it's a little difficult to see because my binary's not perfect. I should actually,

00:07:10

you know what, I should have typed these out. Hold on... Shazam. Take a look at that. Through the magic of video, I have already typed all of these up into binary. Now, let me go back to what I was talking about. We've got 192.168, and then here's our binary bits broken up, and I put the decimal number next to it. You see

00:07:31

0,1,2,3,4,5, and then down here I've got 13, 14, 15. Alright, the concept of route summarization is to take the bits that you have found that are similar, that are the same between all of these routes and group them together. So we look at our..our routes right here. We've got 192. That would be in binary, 8 bits that are all the same, right? 168, eight bits that are all the same, because every single one of these networks start with 192, and every single one starts with 168. Now we come to the third octet, and we look and we see, ok looks like, all those are the same, all these are the same, all these you can see my little lines going down; let me, let me, actually draw a perfect line right here, right...kachunk...kachunk.

00:08:24

There. You see my magic dividing line? That is where the bits start to go different. So, what I could say is these have 8, 16, 17, 18, 19, 20. So, four extra bits here. Twenty bits that are all the same. So the perfect summary route that router 1 can advertise to router 2, is 192.168. .0,.0, slash 20. Notice I started with the very first network in my list. 192.168.0.0 so that that is going to be what I start with and 20. Now if you're thinking about this in terms of subnetting, if I had a slash 20, that would be 255.255.240.0, if I were to break this into binary my subnet mask would be 11110000. My increment, thinking back to subnetting here, would be 16. So, if I were to take 192.168.0.0 and I were reverse engineering this if you will to find out what my network ranges are, the first one would be 192.168.0.0. Second one would be 16.0, 32.0, and so on. So a /20 represents 0.0 through 192.168.15.255. Perfectly encompassing all of these routes that I have behind router 1. So router 2 now has the perfect route on its routing table. All of these can be suppressed. Now before I expand more on...on

00:10:03

the specifics of the summarization, and kind of growing it a little bit; I want to mention what that does. Number one, it accomplishes our goal - larger routing tables equal slower routers, router 2 now has a smaller routing table. Second, is it suppresses

00:10:18

updates. If one of these networks go down, as I was mentioning before, router 1 no longer sends an update to router 2, and router 2, flooding the rest of the corporate network with that update, because router 2 doesn't care. It doesn't know 192.168.1.0. It just knows the big summary, so there's no purpose in sending the notification.1 is down, because router 2 doesn't really even know about the.1 network. It's all hidden. So we accomplish our two major objectives by putting that perfect summary route in there. Now, this

00:10:54

summarization example is perfect. Meaning in the real world, I mean it would be awesome if router 1 had those networks behind it, but unfortunately, router 1 or our organization, just went through a growth spurt, and they just added 192.168.16.0 behind router 1. D'oh, totally goofs things up. Because 16 in binary, if I were to put it in here, would be 00010000. Totally goofs up my summarization route. Now, some of you might be thinking, well, we can fix that. Right?

00:11:29

We can, we can take that line of yours right there... Let's see if this works. Grab my line, and we could move it over. Look at that. The power of animation. We can move that line over and now you've got, that would be the first three bits..chum chum... are the same.

00:11:48

So my new subnet mask would be 192.168.0.0/19 because we've moved our line back a bit to catch our extra 16 network that we added down here. That would be a solution and you're absolutely right in thinking that way that router 2 would now still only have one route on its table. But when you move that line back you

00:12:14

didn't just catch the 16 route, you caught 17 (0001). You caught 18 (10010). You caught 19 (10011). Because all of those have the same three first digits, or three binary bits and the last five are different. So you've encompassed a lot more networks than just sixteen by doing that. Now that

00:12:38

may be okay, but that's also I mean this this by the way will go down, dot..dot...dot, all the way to 32 because by moving our line back one, our new increment has become 32. So, we've encompassed networks all the way up to, I guess you could say, 31.255 would be the last network encompassed in this. 32 would start the next range. Now that's a lot of networks to do. So let me show you what

00:13:02

most people will do in the real world. If you have growth, router 1 will say, ok, I've got 16. I'm going to keep advertising that summary route this /20... sorry it's getting a little scribbly here... this /20 will be advertised to router 2, so it encompasses the first 15, and then I will advertise 192.168.16.0/24, as the separate route. So, in that logic, it's a lot better to

00:13:32

have two routes in router 2's routing table than it would be have seventeen, 0 through through 16, so we're still accomplishing running efficiency, but we're not grouping a bunch of networks that router 1 does not have. So as router 1 keeps growing, you know later on they add.17 and .18, and.19, those routes will be advertised individually until the organization reaches the point that they say, okay, we've got enough networks behind router 1 now. We can safely move that binary line back in our summarization to a /19, and encompass 0 through 31 networks, in that one summary route. So that is the idea of summarization and

00:14:15

that key concept is what lights the way in OSPF, and why OSPF is such a powerful routing protocol. Now that you have the concept of summarization under your belt, we can move into the ideas and terminology behind OSPF. Half the battle in learning this protocol and this is a complex protocol, is understanding the terminology and the whats and whys that are used in OSPF, and the most foundation of all the terms is the concept of area. An area in OSPF is a group of

00:14:51

routers that all have the same routing information. See here's the idea. When you have a network that continues to grow bigger and bigger and bigger, the routing tables on all the routers begin to grow bigger and bigger and bigger as well. So what we can do is split our network into groups of routers, like I can have you many routers within an area here.

00:15:12

And all of those routers would have the exact same routing information. Here's a good analogy to describe it. In the trunk of my car I have a Rand McNally's road map of Arizona. Now also on the wall in my office right here, I have a world map. It's...it's actually an area code tracker that shows me area codes

00:15:36

all around the world. And it's...it's this big world map that I can just look at and see area codes. Now if I were trying to figure out how to get to the mall, which is about 15 miles from my house. Would it be easier to use the Rand McNally road map in my trunk or would it be easier to use the world map sitting right here on the wall? Well, it would be easier to use the one in my trunk because it's focused on specific areas of Arizona. And instead of looking at the

00:16:06

world map and going, man, all these roads are so small. I can't...I can't see you know, could I use the world map? Yeah, maybe, you know if I can look close enough, and they actually put the road small enough on there. I might be able to do it but it would be a lot harder because

00:16:18

there's so much more information I have to weed through to get there. But the one in my trunk is just more focused. That's the idea of areas. Once your organization grows too big all of your routers will have to process all that information. And every packet that they get, it's like they're looking at a world map of your organization. And it's going to slow them down. So, by breaking

00:16:39

it into areas, you could say, okay well area 0 represents we'll say Arizona. Area 2 represents Florida. Area 1 over here represents California and the United States. And we have these specific areas that group together similar routers. Now, just to give you a random guideline. CISCO recommends that

00:16:59

an area never be more than 50 routers. So, as your network grows, you can begin dividing into areas. Now, that is...that is a guideline. That is not a hard and fast rule. So now that we see what areas are, let's talk about the routers that make-em up. Inside of the areas, and I'm gonna stray

00:17:19

straight from talking specifically about the backbone and types of areas and stuff like. I'm gonna first talk about the routers. Inside of an area, you'll have internal routers. And these are routers that belong to an area. That internal router connects to area

00:17:33

0 and knows nothing but area 0. In area 2, I have another router. That router is an internal router. In area 2, and it's...it knows nothing but area 2. These routers that sit between areas are known as ABRs. Area Border Routers. Now these are usually the beefier routers in your network. The ones

00:17:55

that have a little more processing power a little more memory than the rest, because these routers have the road maps for two or more areas in the routing table, so they have to be able to process and look through, it's almost like two page of pages of the map, rather than one page. The big point about

00:18:13

an ABR that you'll want to know, is that an ABR is the one that is able to summarize. Summarization. Now you know why I covered that key concept on on, a page ago because if you didn't know what summarization was all about, the whole design of OSPF wouldn't make any sense. And when you're designing these areas, it has to be

00:18:38

a hierarchical design. And what that means is that you group similar subnets in similar areas. So, for example, in area 1 you know I've got my 50 routers, and maybe over here I do 172.16.1,.2,.3, all of these different subnets, all /24s we'll say for ease. And I've got all these different subnets. And the ABR

00:19:00

as it advertises area 1 to area 2, can sum that up and say, oh area 1 is all about 172.16.0.0/16. Yes I'm using some cheap summarization, just for easing here, some easy stuff. But at the same time, you get the concept. The area 0 backbone routers, they don't need to know anything more about area 1 then that one route. So 50 plus routes summed up in one. Same thing with area 2. Maybe this is 172.17.1,.2,.3, and so on... And we sum that up as it comes in the backbone. And the backbone

00:19:36

has a hierarchical network of its own. If you don't design your network right with OSPF, it will tear you apart, because the ABRs will not be able to summarize, and there's no point in dividing into multiple areas. And let me emphasize that. The whole reason that we even use multiple areas is to summarize.

00:19:57

If you don't summarize when you break into multiple areas, you're defeating the whole purpose and you're just causing more processor cycles on all of the routers. So, when you're setting up an OSPF network, you have to be very careful where to place things.

00:20:10

If I were to go to area 1, and just say, ah, ah, let's you know let's 192.168.1 over here. Ah, let's throw that.10 network... over there. You're...you're shooting yourself in the foot, because you can't summarize that in a hierarchical format. That's known

00:20:24

as an IP address hierarchy. So, let me hit the specifics that I have here. All areas, the rule of OSPF, all areas must connect to area 0. That's what's so special about area 0. It is considered the backbone of your network and all other areas must connect over here as your network grows larger and larger, things must tie into that area. All routers within an area have the same

00:20:50

topology table. And if you want to emphasize that, that means road map. All of the routers in area 0 know everything about area 0. Even the routes that they're not using. The backup routes, you know, and they know everything. And that's fantastic because if a route goes down in that area, the routers, wham converge in a snap. They're able to find those backup routes

00:21:12

that they have in their road map. They just pull the road map back out and regenerate the routing table. Now let me emphasize the difference here. All routers in the same area have the same topology table. Or they all have the same roadmap. But, every router within the area will have a different routing table.

00:21:34

Hmm, let's talk about that. We've got, we'll say, this...this router up here. This area 0 is represented as Arizona. Maybe this router is what connects to Phoenix. This router over here connects to Tempe, that's another city here. And this router over here connects to Tucson.

00:21:51

So we've got, you know, these...these three different routers. Now, in Tempe it'll have the road map of the entire area 0, the entire backbone. Tempe knows how to get to Tucson. It knows that it has a backup route to go to Phoenix to go to Tucson, but it can also go to whatever the city is. Scottsdale we'll say. And get to Tucson. It's got

00:22:09

all this information so if its primary route through Scottsdale fails, it just looks back at the road map and says oh, I've got another route through Phoenix. That's meaning the same topology table. All routers in...in area 0 will have a different routing table because they all start from different points.

00:22:26

So, Tempe will say, my best route to get to Tucson might be through the Scottsdale router. Whereas Phoenix will say well I've got a direct connection to Tucson down here. I'm going to use that as my best route to get to Tucson. So even though they have the same road

00:22:40

map, they all generate different routing tables. It's just like, I mean think about it logically. If you have the same road map in your trunk that somebody else has and they live some completely different place than you, their best routes around the state are going to be different because they're starting point is different. They...they are in a different place in the

00:22:58

state, so they will generate a different routing table. The goal of OSPF is to localize updates within an area. Whenever something happens in area 0 everybody knows about it. But, area 1 should not. Because we should be summarizing to area 1. And area 2 should not. So only things that happen in area 0 will stay in area 0. It's like our Las Vegas mantra. What happens in Las Vegas, stays in Las Vegas. Same thing here.

00:23:26

What happens in an area stays in an area. Finally, and I talked about this; requires a hierarchical design. You must design your network right. Oh, there is one more thing. Let me erase all this chicken scratch. The last term I want to throw out at you is this one over here tucked in the corner. The

00:23:45

Autonomous System Boundary Router or ASBR. The Autonomous System Boundary Router is the router in OSPF that connects to networks outside of its own. This is not another area. This is a completely different network. So it could be a network that is running Rip over here.

00:24:03

It could be the internet and I would say that's the most common network that the ASBR connects to. Others...there's many different things that...that this could be. But the ABR and the ASBR are the only two routers in OSPF that can do summarization. Between areas and between completely different routing systems.

00:24:23

The last OSPF concept I want to talk about is how OSPF forms neighbors. Unlike the Rip protocol, OSPF will form direct neighbor relationships with the routers it wants to speak with. Rip just walks up to the ethernet line and says, hello everybody, sends out a broadcast to everybody. These are the routes

00:24:42

I know about. It doesn't actually form neighbor relationships, it's just the other routers happen to hear it saying hello everybody, and adds those routes to its routing table. They don't know about each other directly. So, in OSPF, routers come up to each

00:24:56

other and say, hello router, hello, and they start exchanging routes between each other and then they maintain that...that neighbor relationship using something known as the 'hello protocol.' It's not just what I'm saying. That's the technical name of the protocol. Now

00:25:10

hello messages are sent, when you configure OSPF on whatever ...whatever interfaces you designate. So, if I say head out serial zero zero then it will start saying hello and trying to form neighbors on that interface. If it does, these neighbors will meet and they will exchange routes and now we have a synchronized routing table. In OSPF, these hello messages are sent

00:25:32

once every ten seconds on broadcast or point to point networks And once every thirty seconds on non-broadcast multi-access networks. Those are things like frame relay which we'll talk about later. The idea is that the more often you send hello messages, the sooner you will know if a neighbor is down, because they'll stop responding to your hellos, and the faster you can change over to a backup route.

00:25:57

Now, a lot of people in the OSPF world will tune this hello timer down, to a second or maybe two seconds. So you're just sitting there going, hello hello hello, making sure that they're online because you want to be able to detect that failure extremely fast. Now, when you and I say hello we think of a greeting.

00:26:18

Like, hello how are you doing, or...or something to that effect. But when OSPF sends a hello, I want you to think about it like an envelope with hello written on it. And when that hello message comes across, the router opens that hello envelope and sees all of these specifics inside of it. It will see things like the router ID, which

00:26:38

is the name of the OSPF router over here. It says hello, my name is, and the router IDs is an IP address. It might say 1.1.1.1 and the router will say, well hello, I'm 2.2.2.2 thats...thats the router ID. In that hello envelope will be that hello and dead timers, meaning how often they're saying hello, and it's kinda rude, but that's alright. It's how...how soon

00:26:58

until they believe you are going to be dead. You know how many hellos they can miss before they say that person must be down. They will advertise their subnet mask in that hello packet. They will advertise what area they are in in that hello packet. Now you notice some of these messages or I should say pieces of that hello envelope have little stars by them.

00:27:22

The stars, I'll put a little key, star equals must match. Right? They have to match in the hello packets between the neighbors, or else these guys will not end up forming neighbor relationships. I think about it this way. My old roommate that that I used

00:27:44

to live with. Ah, actually met his wife online. He...he had one of those dating, um, dating sites. I don't know what they're called, where you...you match up. Right? And when you go to this dating site... I actually was working with him because I'm the computer guy of the house. And I was showing him how to get on there, and you

00:28:05

know, log in and all that. And, ah, on this dating site you have criteria. And what you do in your criteria, you say, okay, this must match. For instance, you know this...this...this person or this mate that I'm looking for must have blue eyes. They...they must have an adventurous spirit. Meaning they like

00:28:24

to do adventurous things. They must have, you know, and you list your must-haves. And then you list your, well you know, it would be nice if they had, um, pink painted toenails. I don't know. I'm just throwing stuff out there. You know. But you know if those don't match it's okay. In the

00:28:39

same way, our routers are online daters. They are sending their little hello messages with each other and inside of there are criteria that must match. For instance, if this router 2 over on the righthand side says hello once a second and the one over on the left says hello once every ten seconds then it's gonna say, I'm...I'm sorry. We don't match. We're not compatible

00:29:03

with each other. And at that point they will choose not to form a neighbor relationship. Now, a lot of these things that you see in this hello packet we haven't talked about yet. And we will talk about but the ones with stars, if they're not matching, the neighbor relationship will not work. And that's the number

00:29:19

one trouble shooting criteria we have with OSPF, is making sure that all these things match. Otherwise routes won't be exchanged. That should be enough of the OSPF concepts to get us going. As we continue this in the next video we'll be able to see how these concepts apply in our configuration. But before we

00:29:41

do let's wrap things up here. We first off looked optimization at its best, or the best way to optimize a router is through route summarization. We then moved into the OSPF terms and network design. And to hit the high ones, area is the most critical. Area

00:29:57

defines routers that have the same topology database or road maps. ABRs, Area Border Routers, is what moves you between areas. And ASBRs, Autonomous System Boundary Routers, are the routers that move you outside of your own OSPF network, maybe to access the internet. We've then finally analyzed the OSPF hello packet.

00:30:20

The hello packet is the foundation language that these these routers will use to communicate with each other and form neighbor relationships. If the relationships don't form routes won't be exchanged. I hope this has been informative for you and I'd like to thank you for viewing.

Routing Protocols: OSPF Configuration and Troubleshooting

Routing Protocols: EIGRP Concepts and Configuration

Access-Lists: The Rules of the ACL

Access-Lists: Configuring ACLs

Access-Lists: Configuring ACLs, Part 2

NAT: Understanding the Three Styles of NAT

NAT: Command-line NAT Configuration

WAN Connections: Concepts of VPN Technology

WAN Connections: Implementing PPP Authentication

WAN Connections: Understanding Frame Relay

WAN Connections: Configuring Frame Relay

IPv6: Understanding Basic Concepts and Addressing

IPv6: Configuring, Routing, and Interoperating

Certification: Some Last Words for Test Takers

Advanced TCP/IP: Working with Binary

Advanced TCP/IP: IP Subnetting, Part 1

Advanced TCP/IP: IP Subnetting, Part 2

Advanced TCP/IP: IP Subnetting, Part 3

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16 hrs 32 videos

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Jeremy Cioara
Nugget trainer since 2003