Original subtitles

>> When I took my CCIE exam, many moons ago.

You walk into the exam, it's a nerve racking experience, and you have to actually sit

with the proctor for about 15 minutes before your exam starts, where they go over all

of the rules of the exam, you know, like when the lunch breaks are, you know,

no talking, all those kind of things.

And when you get to the lab itself, and you look at the book, rule number one of the CCIE is,

no static routes anywhere at anytime for any reason unless explicitly spoken of in the lab

that are you allowed to using things.

What-- now why would Cisco band you from using static routes?

Because you can accomplish anything using static routing and a lot of time.

So we're going to start now, taking the concepts that we saw

in the previous nuggets of subnetting.

And start practicalizing it, if I can make up a word.

Start identifying these networks, putting around our organization

and then moving data between them statically.

So I'm going to start of by reviewing the purpose of routing.

Kind of just again big picture bring us back to it,

how static routing can help us accomplish our goals of routing,

and then look at some configuration and design scenarios for static routing

that actually start doing it in a live environment.

If someone were to ask me the question, Jeremy, what do you do?

I would respond, and I'd say, "I'm an IT guy.

That's what I do."

Now is that a complete answer?

Well, no, because they could say, "Well, can you in a screw in a light bulb?"

And I go, "Well yeah.

I guess I could do that too."

And, "Well, can you ride a bike?"

"Well yeah."

I mean, sure.

There's all this little somethings but when somebody ask big picture, what do you do?

That's the answer.

So when you say, what is a router?

What is routing?

I mean, there's all kind of some things that you could do.

But these are the main answers on the screen.

Number one is stopping broadcasts.

Could we live in a world without routers, meaning, could we just have one big flat network

that we call the internet where everything is all, I mean, get rid of the subnet mask, right?

There's no distinction anymore.

Everything is just one big, bleh, you know, one big network.

That the answer, if there was no concept of broadcast, then the answer would probably, yeah,

I mean, there's other considerations.

But the major constraint is the more device as you add to the network,

the more and more broadcast there are, meaning messages that go to everybody.

So the worst and worst performance, it gets to the point

that would just become unusual, and our computers need that.

I mean, they need some kind of big picture communication.

They need to be able to talk to everything on the subnet, to resolve an IP address

to a MAC address, or to get a DHCP request.

I mean, there're all kinds of reasons for broadcast.

But the number one-- one of the number one goals of a router is to stop broadcast.

So when, we have broadcast on this network right here, they stay there.

They don't bother anybody else.

The broadcast in the Arizona stand, Arizona,

they broadcast in the California office state in California.

The second thing a router does is find the best possible path to does the nation.

Well, that's its goal; one of its goals.

Does it always do that successfully?

No. Why? Well, because there're kinds of sophisticated mechanisms that go into that.

I mean if a router, let's say, we have a router sitting at your house right here, right?

And that connects to a service router, right?

And they connect to other service routers and, they connect to other service routers,

and you know, that we could have all this big spider web of all these connections.

That's what makes the internet so powerful is everything is connected

to everything when it get there.

I saw a picture once on a big post.

You know, those gig posters you see in tech companies.

And it was a map of the connections on the internet.

And it was just pretty much just one big solid blob of everything and they actually have

to use shading of colors to represent the different areas of that blob,

of how money hundreds of connections were coming out of each site.

So there're all kinds of different ones.

So when it comes out to it, this router at the service router has to say, "Okay, I think,

to get to Google, it's best to go that way."

And this one says, well I think to continue that journey,

it's best to go that way, and this way, and this way.

And, you know, even through all those redundant pass eventually finds the best way to get

to google.com, if that's for somebody ends up going.

So that's one of our routers jobs.

And then finally, a routers job is to move the Unicast Traffic between networks.

And if you think about it, it's like okay, well, they stop broadcast and they also stop multicast

which is a message that goes to a group of people instead of everybody.

But they stopped them by default.

But I mean their goal is not to just saver network communication, their goal is to say,

if this happy computer on the left, you know, 192168.1.50 wants to speak to this computer

over on the right 192168.3.50, we can make that happen.

It can come to the router and the router is like, "Absolutely, I can get you there.

Let me send you to this guy and he will get you along the way."

If I want to directly communicate,

that's a Unicast with somebody else, that's what a router can do.

Well, now we come to our first method of routing and that is static routing, the manual way.

Then you might remember when we're talking earlier, I said, switches,

when you put on the box, do what switches do.

They switch.

And now, you don't get many benefits until you configure VLANs

and all the other staff we talked about.

But a router, when you pull it out of the box does nothing.

It has no configuration.

You have to get involve, so you're there with the console cable doing what you do.

So let's say you pull this Cisco Router out of the box and you go

into the FastEthernet0/0 interface.

And you give it the IP address 192.168.1.1/24 or 255.255.255

or 0 that the router immediately goes, Uh-hmm.

I am now one network smarter.

I know how to reach one network and that is 192.168.1.0.

Remember the first IP address; you can't use it because it identifies the network.

That's what the router is used as kind of like the network name,

like I know how to reach that guy, right?

So you're going in and you say, okay, you want me to go under the interface Serial0/0

and I'm going to give it the IP address 192.168.2.1/24.

Now notice, I said, you're giving the IP address 2.1/24, but the router rounds that down,

it goes, okay, well, if I have 2.1, then I must be connected to the 192.168.2.0 network.

I am now one network smarter.

But there and lies the problem is the router is only know how to reach their connected networks.

So I mean, if this computer on the left wanted to ping something over here

on the right 192.168, you know, 2.1, you know, that IP address there,

it would be able to because it would come to it's default gateway which is 192.168.1.1.

Router would say, "Oh, you're trying to ping 2.1."

No worries there.

We can make that happen and it, you know, its kind default like itself.

And so it replies back and says, success.

Now you might be saying, well, can't it ping 192.168.2.2 as well?

Sort of. Okay, let's-- I mean here's what will happen, right?

That's-- I initially was going to say that, but then I back off really quick.

If I said, on this computer, ping 192.168.2.2 which is over here on the other side,

the ping message would go to the default gateway

and the router would be like, "Hey, I can totally get there.

I know how to get 192.168.2.

whatever network and I know how to get there."

So it goes, okay, 2.2, it sends out [inaudible] message saying, "Hello 2.2.

I've got a message for you."

2.2 replies and like, "Great."

So the message actually comes right here form 192.168.1, well, I'd give that guy 50.

1.50 as the source IP address and it goes, "Hey, I want to talk to you 192.168.2.2."

The router looks at that IP address and says, "Well,

that's great, but I don't know who you are.

I don't know how to reach."

So this router over here on the right is the one that pops over the big question.

He's like, "I don't know how to reach 192.169.1.50."

Matter of fact, I don't know how to reach 192.168.1.

anything. I'm looking at my running table and there's nothing there.

Now, you and I at this picture and you're like really, come on, router 2, no.

I forget to give this guy a name.

Router 2, its right over there.

As a matter of fact, you even saw it come in your interface.

You saw it come in whatever interface Serial0/0, don't you know that you have

to go backout that interface to get there?

Nope. Routers aren't that smart.

When you go on to a router and give it IP addresses, it says, okay,

I only know for instance router 1 here on the left says,

I only know how to reach 192.168.1.0 and 192.168.2.0.

Router 2 over here on the right hand side, do I said left, right,

I think I'm just getting everything right mixed up here.

So router 2 on the right hand side says, "I only know how to reach 192.168.3.0 and 192.168.2.0.

So I do not know how to reach this, nor does router 1 know how to reach this."

Do you see the dilemma?

We only know how to reach our connected network.

So static routes allow you to educate the router to new places.

What that means is you and I as Cisco administrators get involve

to tell theses routers where to go.

Clear of this gibberish.

So I as-- if I'm wanting to use static routes,

I would come to router 1 here on the left hand side.

And I would say, hey, router 1 to reach the 192.168.3.0 network which is something

that you don't know how to reach because it's not directly connected to you,

it's directly connected to router 2, but you don't know that.

So to reach this network, you need to go to 192.168.1 or sorry, 2.2.

So essentially, we're using something router 1 knows how to reach to reach something

that router 1 didn't know how to previously reach.

So when router 2, I'm going to have to come in there and say,

router 2 for you to reach 192.168.1.0/24 that whole network.

Now, again, I'm going to identifying the whole network, every device over here on that network.

For you to reach that network, you need to go to 192.168.2.1.

Now does router 2 know how to get to 2.1?

Yes, because it's directly connected to that network.

It knows how to get to directly connected nets, however, it does not know how to get

to the indirectly connected networks.

Now, you can imagine.

So to do an environment like this, you know?

Again, let's make this real.

Let's say, this is an office in Arizona.

Over on the right hand side is an office in Texas.

We connected a WAN link using some service provider in the middle and we've got

that all working now, but we need to tell, you know, the Texas router,

here's how to get to Arizona and communicate to their devices and their IP phones

and make phone calls and get them inside to get to their service.

I mean, so that's the kind of scenario that we would be in.

But you can imagine that when we get to a network the size

of the internet, that doesn't workout well.

Where there is literally millions and millions of networks out on the internet.

We don't want to sit there one by one and say, okay, router, to get to the 1.1.2.5 network

or 2.0 network go to the internet.

To get to the 1.1.3.0 net, go to the-- I mean, we don't want to do that,

it would take all day, not all day, all life.

So what we would do for that is go to the router connected to the internet

and use what's called a default route.

Now I think I did this early in the series, but if not, this will be the first.

We actually go into the router and say, to get to the 0.0.0.0 network, right, go that way.

I mean the actual route, I mean, when we-- let me get a little bit more into syntax, right?

I want to, before we get into the live can fail,

I'll show you what the actual command looks like.

So on router 1, this is actually in global configuration mode.

I go in there and so I'll put config.

This is kind of the prompt were saying.

This is an IOS simulators, do you know that?

And I type in IP route, think of that as like the, I want a route command, IP route.

I want to get to the 192.168.1.-- or scratch that, we know how to get there.

3.0 network with the subnet mask, it be so nice if we could type /24, but we can't.

With the subnet mask of 255.255.255.0, you'll have to type in the whole decimal subnet mask.

Then, so to get, if I want to route to this network, then I'm going to go

to 192.168.2.2 which is this one.

This is the actual command.

This is IOS simulator, right?

This is the actual command that I would type in on router 1 to make it happen.

And I would go on the router 2 and type the same thing,

but instead substitute 1.0 and substitute 2.1.

We're going back to the other direction, right?

So that's what it looks like to put in a static route.

So when it comes to a default route, we come to the command.

It would be IP router.

And the command is actually 0.0.0.0 as the IP address-- let get this little arrow out here.

Then, we would type in 0.0.0.0 as the subnet mask followed

by whatever IP address are ISP gives us, right?

They have a router here.

They're going to give us a public IP and they'll have an IP that they use.

So it will be on a piece of paper, they give you.

You'll give them a call, and they'll tell you.

They'll have to give you something that says, okay, go to 68.110.171.90, let's just say 99,

right, which would be the IP address of our ISP.

So what that tells this router, it says, if you don't know where to send something,

go and send it to them because chances are, it's out there somewhere

in the great abyss of the internet.

So millions and millions of routes can dense into one statement known as a default route.

Let me have one more pointer to this and plug-in a question.

Let's say, right, let me see if I can tactfully do this.

Let's say that router 1 had a connection as well to the internet, right?

And so it has that 68.110.171.90, let's make it 90-- no, let's make it 100, 100 routers, right?

And so it's connected to the ISP.

So we've got, see if you can follow where I'm going here.

We've got a static route that says, here's how you get

to the 192.168.3 network or you go that way.

But then, I go on router 1 and I type in the same default route, right?

That's what I would do.

I would go to router 1 and I would say, but to get to everything, 0000, 0000, go here, right?

So happy computer on the left comes in and pings 192.168.3.50 which is this guy over here.

Packy [phonetic] comes to router 1 who is happy computers default gateway.

Router 1, now looks at its routing table to figure out where to going, it says, "Okay.

Well, it looks like keeping 192.168.3.50.

It looks like I have a route that says for 192.168.3.

anything, go ahead and send it over here, right?

But then, I look and I have now a second route.

And it says, send everything to the internet, okay?

The problem, which does router 1 choose?

Now, you and I looking at the picture or like, well, duh,

it's over there on the right hand side.

You go that way.

But you got to think like a machine here.

The machine doesn't know that.

The machine is like, I have one route that says, go this way and I have another route

that looks just this tasty and it's saying go this way, which one is better?

We come to the rule number one of routing and this is,

I would say a hugely important rule that so often gets missed.

It is the rule of-- and I'm going to make it up.

If it's not a word, it needs to be.

It's the rule of specificity.

Specificity.

The more specific a route is, the better it is, right?

Look at this route over on here.

I say, IP route 192.168.3.0 with this subnet mask.

This is what specifies the specificity.

I'm going to patent that word.

You like it, don't you?

That's what specifies the specificity.

That's how specific the route is.

It says, I'm a class C subnet mask.

This one down here says, I'm a class nothing, I'm essentially a cache all.

I'm not specific at all.

So I mean, let's make it a little more pertinent.

Let's say, I put another static route in router 1 and I say, router 1 to reach 192.168.0.0

with the subnet mask of 255.255.0.0, right?

We kind of slap a class C subnet mask on a class or a class B subnet mask and a class C address.

So essentially this says, to reach anything starting with 192.168 and then anything

after that, that go ahead and go this way, right?

And I think it's just strain a big chicken scratch.

And meanwhile, I still have this route 192.168.3.0 which says, go this way, right?

So if I'm stuck in that world, if I'm stuck in that decision on router 1, which one is going

to run when, it's the rule of specificity.

Specificity-- I can't even say my own word.

Specificity says, this one is more specific

because it's a more specific subnet mask thus I'm going to go that direction.

Now if I, again, now you guys are subnetting masters, right?

But if I created a third route on router 1 and I said, to reach 192.168.0.0, sorry,

let me back that up, to reach 192.168.3.0 with a subnet mask of 255.255.255.128,

think back to your subnetting skills.

What is that do?

That actually cuts this network in half.

You have two networks in 192.168.3.0 through 127 is one that work, network 1.

And 192.168.3.128 through 255 becomes network 2.

That's what that subnet mask does.

So if I created that subnet mask and I said, okay,

to reach 192.168.3.0 255.255.255.255.128 go that way out to the internet.

Now we have problem, right?

Because when this guy pings 192.168.3.50, it comes in the router 1.

Router 1 says, okay, I have a route 192.168.3.0 with the class C subnet mask saying,

go that way, but now I have a more specific one.

I have a route saying, 192.168.3.0 with a slash 25,

a more specific subnet mask, it says goes this way.

So now this guy ends up routing out to the internet.

Well, let's put these concepts together with a little demonstration.

What I've got here is a small scenario, we've got three routers.

Router 1, 2, and 3 connected all around the different networks.

Now all that is been done to this router is given them a base configuration.

And what I mean by base is given them a host name, set the console port to logging,

synchronies, and that kind of thing.

Gave them IP addresses, 192.168.3.1 and 192.168.2.1 for router 2.

And then over here on router 1, you can see, you know, this guy 192.168.2.1 and 192.168.1.2.

Now, sometimes I find early on in the Cisco occur 'cause I remember it happened to me,

a lot of times I would just start seeing these diagrams

and I would become numb to the real world.

I'm like they are hockey pucks on a screen with some squares and clouds, what is this like?

So, this would be an organization maybe it's a small organization that starting to grow,

maybe they had an office originally.

You know, this would be an office right here.

And that would in California, right?

So, they've got, you know, maybe 50 users sitting here on this network

and they originally had an internet router that was allowing this site to access the internet

but they eventually start growing and they're like, "Hey we're going to move

out to Texas 'cause we stole some customers over there."

So, they brought-- they bought a small little Texas office, you know, 20 or so users sitting

at that location and they just brought up a 192.168.3.0.

Again, very usually when you see 192.168 address thing, you're like okay this kind

of like a small office, homegrown mom and pop shop sort of office,

this just again just the generality of where you see this 192.168 address is used.

So, they now were like, okay well we want to connect our office in California to our office

in Texas, you know, Cisco consultant, Bob can you-- can you make that happen?

So, that's where you come into play.

So, where I would start in I guess and I stripped all these things down.

So, all these have just based configurations.

I don't even have a default route to the ISP which would normally be the--

would normally be there would this have been a real company.

So, we're going to go from scratch, you know,

after we've assigned the IP address is what do from there.

We're going to start on router 1 for no other reason than the fact that it says router 1

and that's where you suppose to start.

So, I'm going go on there just get familiar first of all.

Let's bring router 1 into the picture and just so I can still see the IP addresses,

I'm going to do a show IP interface brief and I'm identifying,

okay Serial0/0 which is this guy right there is 192.168.2.1.

So, that's verified and I've got FastEthernet0/1 which is connected over here,

that's 192.168.1.2 router 3 is 1.1.

So, I'm just going-- I want to make sure that I can ping.

I'm going to do some pings 192.168.1.1 that would reach up to router 3.

Sure enough I'm successful, so this little communication is check,

and I would jump over here to this bridge

and let's just ping 192.168.2.2 which reaches out to router 2.

Okay, so we've got a little check there.

Now, I'm just going to do something really simple.

I'm going to ping a little beyond to 192.168.3.1, right?

Which is connected to router 2, should router 1 know how to reach that?

No, it will not.

But let's prove it.

3.1 and it comes back in its sitting there with the periods fail, fail.

That the period mean request timed out.

We're not getting there.

I don't know how they get to that destination and rightly

so because 192.168.3.0 is not directly connected.

Let's do a new command.

I'm going to do a show IP route.

This command is the life blood of your router.

It shows every single network that the router knows how to reach and when I look here it says,

"Okay, I only know how to reach 192.16.1.0/24 because I'm plugged into it,

directly connected, right out this port.

You see little C, look up at the code, C is connected."

So, I'm plugged into it, I also know how to reach 192.168.2.0.

Its right there Serial0/0, why?

Because I'm plugged into it.

How does it know it's plugged into it?

Because at some point you and I would have gotten on this router

and we would have assigned an IP address and as soon as we assign

that IP address the router goes, "Oh that's what I'm plugged into."

Right? Can you follow that?

So, now I need to educate this router.

I need to say, "Hey router here is, here is how you get to 192.168.3.0, let's do it.

I'm going to go config T, global config

and then this is the command I just showed you on the previous slide, IP route.

So, I'm going to say, "I want to route."

Now, where am I going?

And that there's all this other options that we have here,

but the main one I'm interested is the destination.

I want to reach 192.168.3.0, the router says, "Oh, yeah well what it subnet mask?"

255.255.255.0 or prefixed mask, same thing.

So, class C subnet mask and then it says, "Okay, well how do get there?"

Now, there's a couple ways I could go about this.

I could say, "Well, go on and send it out Serial0/0."

And that that would work okay, but I don't like that.

It's too-- I don't know too vague.

I just-- I deal-- when I deal with routers, I deal with layer 3.

I don't like just saying, yet go out that that interface, just go-- like I feel, I feel like,

you know, when we moved into my house we found these three cats and we kept one of them

but the other two we had to let go and we kind of to come took them to the door and we're like,

"Okay go Cougar [phonetic], go Moe [phonetic] go, bye-bye!

Bye-bye, see you.

Bye." You know door slam.

That's why I feel like is-- if I say to get to this network go

out Serial0/0 well that maybe accurate.

It feels like the router is kind of like, "Okay open the door, go little pockets go.

Go! Go find your home.

Okay go." Now, it'll work in this case because it's a point to point link

and it will reach the other side successfully because that's the only--

it's kind of like it just fell in to a tube and it happen to go that direction, you know,

that it's kind of like there's no other way to go so that's where the little cats went.

But, the best way to do it and I'm saying just to avoid troubles, to avoid weirdness is

to point it to the actual IP address.

Don't say go out this interface.

Tell to reach that, this network, go to 192.168.2.2.

Again, just from the last time this is going to something that you know,

192.168.2.2 to reach something that you didn't previously know, 192.168.3, right?

Good. So, now let's test it.

So, I previously I did the ping to 2.2 successful and then I went to 3.1

and that failed, let's try it now.

Now, we are successful, right?

Because it knows I have to go through 2.2 to reach 3.1.

We can even do a-- let me do this.

I'm going to do, a no IP domain look up now just--

that's a command that keeps it from trying to look up next hop domain names

which just slows this command down to no end.

But I'm going to do a trace route.

Trace route 192.168.3.1 and it just shows that okay, it's only one hop away and I went

through this IP address to get there, just again verifies,

verifies that we went there and it always pings three times.

It always looses the second ping on the trace route.

The final leg of the thing, there's actually a whole article, Cisco wrote up a wire that is,

but for now that's the way that we get there.

Now, here's another serial.

Let do this.

I'm going to do-- try IP interface briefing.

Again router 1 and I'm going to do the same thing ping 192.168.2.2, right?

Feeling good about that, but I'm going to add to it from the source and I'm going

to say come from the source FastEthernet0/1.

Now, what is that?

192.168.1.2.

Now, why am I doing that?

Because what I'm saying is when this guy pings this guy, it's of course going to come

from this source because that's-- it's saying,

"Okay my source IP address is 192.168.2.1 that's the interface that I'm originating this from

and I'm going out-- and I'm going to the destination of 192.168.2.2

that should work just fine but I'm changing the game.

I'm saying no, no, no, how about you come from the source 192.168.1.2 come from this IP address

as your source and try and ping that same destination.

What do you think will happen?

Success or fail?

It's going to fail, why?

Well, because even though it's coming in the same link right here to router 2

and you can watch the dots appearing there, even though it's going

in that same link router 2 now is getting pockets from the source 192.168.1.2.

It's looking at its routing table and it saying, "Do I know how to get to 192.168.1.anything?"

No, nobody is told me how to get there.

So, the pockets are getting and they're being dropped, dropped, dropped, dropped.

Those five drops it does not know what to do with them.

So, what do we need to do?

We got to go touter 2, right?

Let's do that.

Router 2 is in the game and we will do show IP route.

I see router 2 is not very smart.

It only knows about its two connected interfaces,

2.0 and 3.0 which we configured it from the beginning.

So, I need to go into that router 2 and come in if you know this pause the nugget now

and write this command-- write down what I'm going to type in here.

Write down what will fix this.

Okay, unpause.

IP route, 192.168.1.0, even though I want to specifically reach 1.2 I'm--

routers don't do that, well they can I don't want to do that.

I want to say to reach that whole network, to reach everything on that network with a 255.

255.255.0.

Router 2 you need to go to 192.168.2.1.

Again, router 2 knows how to get here, right?

To the 1, so, we're saying use that guy because he knows how to reach 192.168.1.0.

It's like a big train that we're building, you know, one by one by one we bring these links up.

So now, I can come back to router 1 and do the same command, you know,

ping him again from a source of 192.168.1.2 and now we have success, why?

Because router 2 knows how to get back.

He is saying, "Okay.

Now it's coming from the source and somebody just educated me how

to reach this entire network."

Now what about router 3?

Router 3 up here has been out in the cold, he doesn't really know anything.

I mean-- well he knows how to get his connected network, 192.168.1.0, right?

And he knows how to get to ISP, not the internet, he just knows how to get this network

between him and the ISP, so he's got a lot of work that we need to do for him, right?

So it should be pretty fast now that we know what we're doing.

So let me just clear off all this gibberish and let's go to router 3.

Here we are in this blank little config screen.

Let's do a show IP interface brief on him and we see, yup, he knows how to get to his ISP.

He's on that network and he knows how to reach to 192.168.1 network,

but if I do show IP route, he doesn't know anything else.

So he can't get to-- he doesn't know how to reach this WAN link, 192.168.

2 or this network over here and I just prove it to you quickly.

192.168.2.1, we're not getting anywhere.

He doesn't know how.

Control-Shift-6 by the way will break you out of a ping that's stuck

if you don't want to wait for all of it to fail.

Control-Shift-6, you have to hold it all down and, you know,

kind of hit them all at the same time.

All right, so I can add some route.

So I'm going to do IP route.

Again pause the negative.

You know where I'm going and think through it.

192.168.2.0, so to reach the two network, 255.255.255.0 go to, who's it going to?

192.168.1.2, I'm saying go here in order to reach here, right?

Now some of you might be looking at this switch.

I mean like what, what role does he play?

Cable connector?

That's about it.

I mean normally you won't even see this run.

By the way, these guys are all peripheral.

If you download the GNS3 typology that I'm using to create the scenario, this--

I don't even know if I put a configuration on these guys.

They're just there for the picture, but photo app, right?

But this guy is normally drawn, the people don't even draw him.

You see diagrams like this to where you see, you know, these guys.

So the switch just becomes the line because all that guy is kind

of connecting everything together.

He doesn't really participate.

We're going through him.

He learns the Mac addresses but we're talking layer three.

We don't deal with IP addresses.

All that stuff is now assumed that was earlier in the series.

So we can come back here hit the up arrow.

Well let's just prove it now.

I'm going to do a ping 192.168.2.1 groovy.

We're getting there.

Let's go 2.2, groovy, so we're able to reach everything

on that two network, but what about 3.1 now?

Fail. Nothing.

Not getting there.

So Control-Shift-6 break that.

Hit the up arrow a couple of times.

There's my static route and I'm going to 3.0 that network

over there on the right, go to 192.168.1.

same place because router 1 has a static route that gets in there too.

Putting in place.

Bam. Look at that.

Isn't it-- it's kind of cool to do static route?

It's definitely one of those

like I've accomplished something today feelings 'cause you really are bringing up networks.

Now, this works great for networks the size of what we're looking at on the screen.

But the more and more this grows you add four, five, six routers.

I mean the amount of work you have to do begins to increase exponentially,

every new sites that's added you have to go to every location every router and say,

okay, to get here do this, do this.

Now, the key about static routing is it's good.

It works well.

You just need to know when to convert from it.

You got to say, okay it's time to make a leap from static routing to something else

and that's going to be what we talk about in the next nugget as we get into dynamic routing.

One more piece that's missing though, router 3, yeah he's got an internet connection,

meaning the ISP is coming in right here on this cable

but we don't have a route to reach the internet.

So what I need to do is go in here and do IP route, remember I was saying a default route.

Everything zeroes, everything zeroes, 68.110.171.99, Enter.

Now I'm assuming, just made a big assumption that the ISP is actually 99.

Now let me just say, in this scenario there is no ISP and when I went into GNS3

and created this, I actually converted one of my computers and just said, no,

you're a cloud [laughs] and it's not really a cloud, it's just a computer.

I just said, "Look like a cloud," but it's not real.

But that's what-- that's the only thing that I would have to do to bring

that up that internet connection.

Now I'm not going any further.

I'm not making this internet connectivity real and I will later in the series

because there's other things that have to be in place

to make this whole thing work primarily the one being in that net-- network address translation.

We haven't gone there yet.

Now all of these other routers because I'm using static routing need a default route too, right?

So I'd have to go-- this is the beauty of static if you're paid by the hour, you go in there now

to router 1 and I say, okay IP route to get to the internet for you

from your perspective go to 192.168.1.1, right?

So 'cause from router 1's perspective, he's going to router 3

and from router 2's perspective right here, do a show IP route on him.

He only knows how to reach, he's got static, you see that 192.168.1.0.

By the way, we haven't talked much about this yet.

We will. This actually represents the administrative distance and the metric.

When we get to the next nugget, we'll start looking at-- actually did I put that?

I think I did.

What administrative distances how believable is this route?

One is actually a really, really, really,

really good administrative distance that's why almost the best that you can get because you

as an administrator told this router this is what you do, router,

and the router sometimes do its detriment believes you and me.

The second one is the metric as in how costly is this route?

That's when we start talking about, how, you know, how does the router find the best route?

It's going to be the one with the lowest cost.

Now this looks like a really, really,

really good route because it has a cost of zero but more on that later.

So it's saying, to reach this guy with really good administrative distance

and really good costs, go to here in the [inaudible].

So we now have to add in.

But to get to everything else, go to 192.168.2.1.

Again router 2 from its perspective, he says, "I'm going to send everything to here";

and router 1 says, "well I've been configured to send to everything to here";

and router 3 it says, "well I've been configured to send everything to here."

So you kind of create this chain of send to everything and now when I do a show IP route

on any of these routers, this is the first one I'll show you.

You can see that I have this side note this little star.

The star if we look at the keys says, "candidate default"

and you also notice previously it was saying, I don't where I'm going.

I don't have a gateway of last resort, like I don't how to get there.

I'm standing here.

But notice after we put in the static route, its saying, okay now I do.

Now I know if everything else, last resort.

It's kind of like, if all else fails, I'm going to send the pocket to 192.168.2.1

because that's what I was just configured with, with that default route.

So you can think of static routing like a big scavenger hunt.

Ever done a scavenger hunt where, you know, you either have probably a team of people that's

with you and you get envelope number one and then in the envelope it says, you know,

go to a store in the mall that starts with the letter sport.

I guess that's-- obviously I didn't do that with this scavenger hunt.

Starts with the word sport, right?

And do you get-- you go to the store in the mall and the store

in the mall you find another envelope there and it's like, okay,

now got to the, you know, what I mean.

So you kind of keep going with all of this envelopes until you are the first

and you win a price and that's really what static routing is, is we're kind of creating all

of these little links that's the feel that you get as you configure these devices, it's like,

okay to get to the 192.168 go here and when he get there they're like,

no, no, no, actually go here.

But you as the router-- you as the administrator have to go in there

and statically place each one of those envelopes.

In one sense, it's good because you have complete control over everything

and if something fails it's your fault.

You know that you did something wrong.

It's very simple when you look at static routing but also from a overhead perspective,

you can see that can really start being a lot of work especially

when you start having many different past in your organization

and many different sites it just becomes plain overwhelming.

So static routing, works well for small organizations not so well for large.

That being said you almost always find it in every company in some form.

You'll find some device with the static route and put in there.

So we have seen in this nugget the purpose of routing kind

of taking us back, big picture, what is routing.

We looked to how static routing can help us accomplish our goal

of educting the routers manually.

And then we looked at some configuration and design scenarios for static routing.

I hope this has been informative for you and I would like to thank you for viewing.