Now we're going to dive into a discussion, a very short discussion, on
dynamic routing overview. I don't want to waste too much time here because I'd
really like to get into OSPF and cover everything we need to to get ourselves
set up for our next session. But when it comes to routing, for example, we've seen
that we have static routing already with the IP route command and we learned
about that in CCNA. We cover it, not heavily, but we spent a lot of time on it
there. And in dynamic routing, you've got your IGPs versus your EGPs. Your IGPs
are dynamic routing protocols that you run within your autonomous system,
whereas the EGPs you run between autonomous systems typically. And under
IGPs, you get your distance vector like RIPv1, RIPv2. You got your link state,
OSPF, ISIS. You get your advanced distance vector, EIGRP. And then under EGP, you've
got BGP, your path vector routing protocol. So being able to, on the exam,
understand this flow and understand the types of protocols and what they are by
name, good thing to have. When it comes to the term autonomous system, what exactly
does that mean? It means a collection of networks overseen by a single
organization, essentially. So, for example, my company is an autonomous system, your
company's autonomous system, Cisco's an autonomous system, Facebook's an
autonomous system, etc., etc., etc. So everybody is an autonomous system.
Regardless of whether you are officially autonomous system on the internet or not,
think of it that way. So even your house could be considered an autonomous system,
even though it's not like an official autonomous system with its own autonomous
system number, it's still a collection of routers, one router under your control,
when it's all said and done, typically. Maybe you've got two or three routers,
depending on how your home's set up. But in the end, you think of it this way.
An autonomous system is a collection of networks overseen by a single
organization, and therefore I'm going to run an IGP inside my organization,
like RIPv2, ISIS, EIGRP, OSPF. And then between myself and another organization,
or between myself and my service provider, I'm going to run maybe something like BGP,
which is an exterior gateway protocol. In addition, you run like BGP, for example,
if you're connected up to an MPLS layer 3 VPN. But even nowadays, you might be using
BGP inside of your data center. So BGP can be used for many, many different things.
Not just connecting two different autonomous systems together. But for this course,
for this exam, that's the extent of it when it comes to knowing what an EGP is for or BGP.
For example, when we get to our BGP discussion, we'll be talking about eBGP.
That's what the exam objective state. You're not going to be testing on IBGP or anything like that,
just eBGP. So you connecting your autonomous system up to another autonomous system
is what we cover in Encore. Here's a nice little chart I put together for you
with the dynamic routing protocols lifted down the left-hand side. We've got RIBv2, EIGRP,
OSPF, ISAS, BGP. And when you look at the types, you really only have two different types. You
have distance vector and you have link state. That's really all you have. RIBv2 is a pure,
pure, pure distance vector routing protocol. And then EIGRP is an advanced distance vector
writing protocol. Essentially, it has its roots as a distance vector writing protocol,
but there's a lot of advanced functionality with EIGRP that makes it a really great dynamic
routing protocol to use inside of your autonomous system. OSPF, a link state routing protocol. ISAS,
a link state routing protocol. And then when you look at BGP, it's a path vector routing protocol.
So path vector, distance vector, right? And so it has its roots in distance vector,
but it relies on things like attributes and paths and different things like that,
ultimately making it a different type of distance vector routing protocol. But in the end,
we really just have distance vector and we have a link state. And what it really boils down to,
folks, is the difference between distance vector and link state really comes down to
the information that is shared when it's in the grand scheme of things. So when you think about
any type of vector-related routing protocol, so distance vector, advanced distance vector,
path vector, think of it like having street signs. So every router is a street sign. So when you
arrive at a router, there's a street sign pointing you in the direction and how far it is to get
there. That's it. And then you move on and you keep going, meaning that routers only know
essentially what they have learned from all their directly connected routers when you are a distance
vector in nature. And you don't know anything beyond that, except something is out there
somewhere. So if we leave this interface, we follow the sign, we'll eventually get there.
It's like driving down the highway and you see a sign that says New York City, 97 miles. Okay,
well, you know, if you just keep going, you'll get there in 97 miles. Now, maybe you'll have to
ramp off, maybe you'll have to take a Y exit or something, but again, there'll be a sign at that
point that tells you what to do, a sign that'll tell you what to do, a sign that'll tell you,
that's what distance vector's like, path vector's like a distance vector, okay?
Whereas link state, you learn from everybody in your environment. So you learn from everybody in
your environment and you can build what's called a topological map. So something like OSPF and ISIS
has a complete view of the environment. And so they can make their decision based on those
complete views, whereas distance vector makes their decisions based on what? Based on what
they've only learned from their directly connected neighbors, right? Now I'm saying
one is better than the other, right? For example, EIGRP and OSPF are really great
for inside of your autonomous systems. EIGRP is very flexible, it's very easy to implement.
But OSPF is very scalable and it is much more difficult to implement and much more difficult
to work with. But primarily what we see in enterprise environments are EIGRP and OSPF.
So chat in folks, are you using EIGRP or are you using OSPF?
Conrad says, I've heard distance vector being called routing by rumor. Yes, because as I said,
you only learn from your directly connected neighbor. So your neighbor has learned information,
they've made a decision based on that information, and then they share that
information to another router. So I've learned based on rumor, that's all that means. I've
learned based on rumor. I haven't learned from everybody, I've learned based on rumor,
does that make sense, Conrad? So yeah, so I'm not going to know about everybody else,
I'm not going to know the information directly from the source, I'm only learning it from the
directly connected neighbor. So whatever they have learned, whatever they have decided,
that's what they teach me. They teach me their decision. So it's like playing the old game of
telephone as a kid, right? Somebody says something and then you got to repeat it,
repeat it, repeat it, repeat it. If it gets messed up along the way, it could get pretty bad.
Same idea with distance vector, routing by rumor. That's essentially what it boils down to.
Right, so we have some people using EIGRP, we have some people using OSPF.
So if you primarily use EIGRP and you've worked a lot with EIGRP, for the certification exam,
it's going to be all about OSPF pretty much when it comes to configuration verification. So you'll
have a pretty big learning curve ahead of you. But for those of you who have OSPF, then you have
quite a bit of information under your belt that is going to help you with the certification exam.
But regardless, I'm going to go from the beginning soup to dessert when it comes to
OSPF configuration verification troubleshooting when we get to that discussion. So this chart
may come in handy on the certification exam because if they ask you a simple question like
which of the following protocols are distance vector, or maybe there's a drag and drop that
says drag the following attributes to the following types of protocols, maybe you have to do that.
Which ones are Cisco proprietary versus not? So EIGRP, Cisco proprietary, doesn't work on other
Cisco equipment. Not technically true. And the reason why is because in 2011, Cisco made an RFC
about EIGRP. And other vendors could implement EIGRP on their devices if they want to free of
charge nowadays. But it's still Cisco proprietary, meaning Cisco controls it. And you must implement
on your routers exactly as Cisco tells you in that RFC. We've talked about metric earlier today,
memorizing that's not too bad for the certification exam, EGP versus IGP. And then of course,
your administrative distances are really important to memorize for the exam. So earlier, somebody
said, hey, should we memorize our administrative distance? Yeah. Memorize your administrative
distance. Memorize your metrics. Memorize EGP versus IGP. Wow. That's not good. You see that
flash? That was a camera issue. All right. Fingers crossed we get through class.
Fingers crossed we get through class. All right. If not, we'll have to do it without
camera. And we'll just do it with audio and slides. Now, I've also put this together for you.
This is available in your exam crash that is in your campus environment. So you don't have to
copy this page right now. You don't have to take a screenshot of it because I am in the way.
But in your exam crash, you will find this page. But if you did want to take a screenshot,
I'll just move out of the way right now. And for those of you watching a recorded video,
you could pause it and take a screenshot if you want. But the goal here is for you to be able
to compare and contrast. So the idea here, especially for this exam, is to be able to
compare and contrast EIGRP and OSPF. This is something that is in the exam objectives.
And it's quite possible you could get a drag and drop, a multiple choice question, anything like
that. So you really have to take the time to make sure you know what's on here. That's why I put
this together. And I'm not going to bore you. And I'm not going to walk you through this and hold
your hand in regards to this. This is just like the fundamental behaviors and characteristics
of OSPF and EIGRP. So when you look at something like summarization,
you'll see that EIGRP supports autosummarization. But OSPF does not support autosummarization.
So it may be something you need to know. It also shows that EIGRP, you can do summarization
manually on any enabled interface you want. Whereas something like OSPF, you can only do
summarization on ABRs and ASBRs. Know your administrative distances. They're listed there.
Know that one's distance vector, one's link state. Know all of these different things.
You are not going to be testing on configuration verification of EIGRP. You're not going to learn
about EIGRP, which frustrates me to no end when it comes to the Encore course and certification exam.
They are so focused on OSPF and they are now expecting you just to know some attributes
of EIGRP. That's silly in my opinion. In my opinion, if you're going to go ahead and do
EIGRP, you might as well teach everybody EIGRP from soup to dessert, just like you're doing for
OSPF. But they're not doing that. They're not testing you on that. So what I've done here,
if you know these attributes, you know these attributes. Anytime they ask you to compare and
contrast EIGRP and OSPF in the exam, you're going to get the answer right.
Are all of my slides up to date? They should be. Why are they not? Are they not?
So when you talk about slides, I assume you're talking about, for example, these slides
right here, the class slides. So I'm talking about here the exam crash. That's where you're
going to find that one. So it's under the exam crash, download, and it should be near the beginning.
No, did I take it out and put it back in the course? Oh my gosh,
I think I took it out and put it in the course. All right. So, oops.
What did I do there? Okay, yeah, I guess when I updated it and we updated it, we took it out of
the exam crash. Okay, it's not in there anymore. All right, so cool. And if it's not in the slides,
I assume you're saying it's not in the slides. So I'll get the slides updated to make sure
they're in the slides. So let's check it out here.
Okay, so it's not in the slides anymore. So I'll get the slides updated to make sure they're in the slides.
So let's check it out here.
Oh, there it is. It's right there. Yeah, so it is in there.
All right, so what page was that? 344, if you want to know, folks, 344.
All right, so yeah, I did move it out and I put in the slide deck.
All right, if you're experiencing any buffering or latency, it's probably on your end. I
I recommend you refresh your browser. That would be your best option.
I'm not seeing any issues on my end and I'm not having any dropped packets or anything like that
based on my counters and statistics. So everything looks good on my end. So maybe refresh your
browser or anything like that. That might be what is causing your problem. Maybe your connection
is just not good enough right now. All right. All right, so this is on you. Make sure you know
this stuff, folks. All right. All right. So that is it for our dynamic routing protocol discussion
or overview. Good information there just in case they ask you multiple choice question,
compare, contrast, drag and drops, anything like that for the certification.