Original subtitles

>> Wow. We just started into routing and we're already into a topic of speaking binary.

Now, I know some of you have gotten your feet wet in networking before.

You know where this is going.

The thing, if he's talking about binary now that means subnetting is next, "No, aaah."

You know, the most feared topic in all of networking.

But don't worry you'll get and when you get it you're going to feel like a ninja.

It's one of those things that really puts all the pieces together

of how these networks really work and binary is a prerequisite skill for that.

You have to get how computers and network devices really think.

I was thinking about, you know, that walk like an Egyptian song, The Bangles has--

they're singing like, "Walk like a Cisco router."

There's some kind of parody waiting to be written for that.

So that's going to be it's like you're thinking like the router when you're thinking a binary,

and you're thinking like technology in general.

Really, binary is just a zero or a one, an on or an off.

You probably have heard stories that people that used to write computer programs on punch cards

and feed punch cards into these machines which, you know, just kind of have holes

in them representing ons and offs and all that.

And these fancies are computers and technology are--

really all we've done is gotten faster at processing zeroes and one, you know,

it's where can get all these fancy graphics and everything like that

because our computers can just look at a bunch of zeros and one's really fast

and put them all together, and that's why our graphics

and everything else that we do are so short-noticed.

So, what we're going to do in here?

Review the basics of IP.

Kind of put us back in the context.

Look at Rico and Bob I'll wait for that explanation till then.

And then this nugget is really just looking at one major skill,

converting from decimal to binary and back.

Now we can't just jump into binary without giving ourselves some network context first

to really put us in a frame of mind.

When we're talking about binary we're talking about IP addressing and how we break

up our networks to fit our organization.

And right now, we are using IPv4, I'll talk about IPv6 in a little while,

which is going to become a major player soon.

But for now, IPv4 is where we're at and, I mean, we've seen these-- these examples.

We've got an IP address that looks like this, 10.10.10.1.

Now what we're looking at there is a 4 byte address, each one of these being one byte.

Now you won't actually see-- and by the way, that isn't why IPv4 got,

I know everybody mix the link they're like, "Oh, that's-- " No, has network got his named from,

but you won't hear people talk about IP addresses in terms of bytes most of the time.

You won't hear people say, "Well, it's 4-byte address,"

even though that is technically accurate,

because when we're working an IP, we usually go down a level.

You might remember early on the series, I showed you how computers deal with size and I said,

"Okay, we've got the byte, we've got the kilobyte, we've got the megabyte," you know,

when I was going larger and larger, larger and larger, if I could talk in right, I, you know,

getting bigger until a gigabyte, terabyte, blah blah blah blah blah, and I said, "blah blah."

That's not how we think about things in the network world.

Everything in the network world is related to what?

Bits, right?

You remember that.

So we go down a level to the bit and it messes

up the whole scheme 'cause this is all a thousand, a thousand,

a thousand, you know, a 1024, whatever.

And so down here, we go to eight.

There are eight bits in a byte.

So when you see the number 10 and you go "Okay, that's one byte of data.

You go, "Okay, well, really it takes eight bits to make that number 10."

Okay, what does that mean?

What is a bit?

A bit, I started off on the objectives, is a on or an off, a zero or a one.

So when I look at the number 10, I go "Okay, there's actually eight zeroes and ones

that are necessary to create it."

It's actually that.

And by the time you're done with this nugget, you'll be able to do that too.

You'll be able to look at numbers and just go "Okay, I kind of see it now.

Now 10 is a very simple number which is why I can look at it and do that."

But you'll be able to at least work it out and figure

out how did I get this number from the number 10.

Now, okay, okay, great Jeremy.

So, why is this relevant at all?

Well, because in the network world, we don't work in terms of nice, clean boundaries.

Like we have, so far in this series, worked with what I would call classful subnets.

Meaning, we're sticking to the original classes that were created back in the 1960s

when whoever you're convinced that created it, created the, you know,

IP protocol and developed that technology.

He said, "Okay, well there's going to be a class A, B, and C address and we're going

to have a subnet mask of 255-000", you remember this?

255-000? "So class B, 255, 255," come on it's going back here, right?

So we've got all these different classes of addresses that were created originally,

and that's kind of what we stick to.

And we said, "Okay, well these are the nice, clean boundaries."

So when we take an IP address and combine it with a subnet mask,

it gives us what portion of the IP addresses?

The network in which portion is the host.

So let's take this.

If I combine that with a class A subnet mask, if I take 10.10.10.1 and I say subnet mask 255 000,

right, then I'm able to look at it and then go "Okay, well," actually 10 represents the what?

Network, right?

And all of these other stuff represents what host you are on that network.

So that's, I mean, that's a lot of host when you realize each one of these values can go

to 255 actually comes to 16,777,214 hosts on one network which is insane.

You can't have 16 million hosts on one network, it's just too big.

That means one broadcast from one of those host will go to 16 million buddies.

They're all sitting there connected to the same network.

It doesn't scale.

I mean, rough, rough, rough numbers.

I mean, somewhere around I would say at absolute most 500 devices or so.

Now that's-- I'll say I've seen that recommended from Cisco

but there is no document I can point to, to say "That's it."

But I mean, somewhere around 500 devices, that's about as big of a network as you want before,

you know, broadcast are starting to get a little crazy.

So 16 million, not even the ballpark.

So what we do is we say, "Well, if we can't do that then let's take"--

I've got to go back to purple, I can't stay red.

Let's take that 10.10.10.1 and line it up to a class B subnet mask, right?

See what I'm doing here?

I'm saying, okay, well I want to take that bar and move it over.

So this now represents the network and this represents the host

which makes it a little more reasonable.

I go, okay, well that's good.

It's not 16 million hosts.

Well, if you actually total it up, that's 65,536?

Maybe 4? Okay, I get it.

Come on, I can't remember all of the numbers.

I'll say it's 65, 530 something IP addresses that are all on the same network.

I think 36 that are total and 34 as usual but we'll go with it.

I digress.

So it's still way too big.

And that's why you see this class C subnet mask getting through on everywhere,

it's essentially lazy subnetting to where somebody takes an address like this

which is technically a class A address, again more on that a little more--

a little while, and start putting class C subnet mask all over the place, 255, 255, 255 and zero.

So what that does to say, "Okay, this represents the network.

All of the computers on that network have to start with 10.10.10.

And then this last one represents the host that you are on there and that gives you 254 usable,

256 total addresses but 254 usable addresses, because you can't use the very first

or the last IP address of each range.

Again, more on that as we expand in the subnetting.

I just want to give you the context here.

So these are big jumps, I mean, to move from 254 to 65,000.

I mean, come on, isn't there something in the middle?

I mean, can't-- I'd to say, "Well, let's can I move to like, I don't know,

500ish or a 1000ish addresses on the network?"

And the answer is yes you can.

Yes, you can make those kind of jumps, but in order to do it, you have to know binary,

you have to know that when you see a subnet mask of 255, 255, 00, you're looking at it

in what's friendly to us as human beings, a decimal number, but behind the scenes,

there's actually a binary number that lines up to it, as a matter of fact 255 is 11111111,

eight 1s that they go inside of that that make that number.

And what I can do is say, "Well, instead of just trying to change the decimal, you know,

in trying to make that make sense,

I have to work with the binary behind the scenes 'cause that's where it really goes, "Oh,

that make sense" and that's how the routers deal with it.

So, these IP addresses all operate at layer 3.

So again, we are in the routing section now, we have left switching behind for the time being.

So layer 2 devices, Mac addresses, all of that, that's back there.

We're now moving to routers which are getting us off of our networks.

I mean, the switches in the layer 2 devices, these guys are good for local connectivity

like I want to talk to the computer down the hallway.

But when I'm talking to the internet or I'm talking to a server not on my network,

that's why I need the layer 3 connectivity, that's where the routers come in.

So think of that last slide as kind of a review of where we've been

and at the same time a sneak peek of where we're going.

I know there's some pieces that don't quite fit but they will.

That's what subnetting is going to put together.

[laughs] How do you even transition from that into, I mean, you're looking at this--

how do I transition into Rico and Bob?

I don't know.

So I'll start off by saying "Yes, I did draw that myself.

Yes, it took longer than I would like to admit to draw something like that."

But here we go, Rico and Bob are really kind of a tale

that puts the subnetting or binary pieces together.

So Rico is a brilliant scientist who has invented a construction brick

that is both lightweight and very sturdy.

And I'll add in another one and inexpensive.

So, you know, construction bricks are typically concrete,

you throw them on the ground, they smash in a million pieces.

You know, so he's-- he created this brilliant brick for construction.

And so a brilliant scientist, he's not much of a businessman, he took all of these bricks

that he's manufactured and just put them into a big old pile in a warehouse.

And he hired Bob, his sidekick, his handy assistant to help him.

So, you know, our first construction guy comes up and he's like "Hey,

Rico, I heard you built this brick.

I want 210 bricks."

So Rico turns around and goes, "Hey, Bob, 210 bricks.

Bob, "Okay."

Runs inside of the warehouse, you know, brings a brick to first, "Here we go.

Okay, one brick" runs back to the warehouse, and two brick,

brings back up and "here we go, Rico."

And so he's-- that's-- this is sweat, do you feel it?

It's pouring off of him.

He's in the air levitating right now.

He's jumping from to-- he's trying to move so fast and he just cannot keep up, you know.

And so, you know, do you see the concern?

Again, it took some time here.

The concern on this man's face, he's like, "Wow!

210 bricks, I'm concerned.

I want 120 bricks."

This is going to take forever.

So, but, you know, I'm not angry because I'm going to get bricks eventually.

But this little man, not only he's the shortest man in the line causing frustration right there,

but also 15 bricks is all he wants but he has to wait

for these other two so you feel the anger on him.

So, you know, somewhere around brick 63, Bob collapses like, "Rico, close the door,"

you know, it's like in the door "Ching, ching, ching, ching," those little metal thing.

And so Rico's like, "Okay, Bob, you're all right", and Bob said, "We can't do it.

We can't run the business like this", and so he was like,

"We've got to come up with a new system."

And Bob-- well, Rico is the brilliant scientist, Bob brilliant kind of organizer, if you will.

So he says, he goes "No, no, no", he's like, "We need-- we need to get pallets", he said,

"I'm going to make a pallet of a 128 bricks."

This is where my art falls apart.

So a pallet of 128 bricks.

Let me-- a second pallet of 64 bricks, a third pallet of 32 bricks, you know,

and we got these bricks that are sitting on it.

A fourth pallet of 16 bricks, a fifth pallet--

I'm not really needing the pallet at this point, but hey why not.

It's still a bundle of eight bricks.

We'll take a pallet of four bricks and then, well, a pallet of two

and then just the single brick pile.

So we've got all of these bricks.

So it kind of takes this file and organizes in all of these pallets,

he goes and buys himself a fork lift with their new found fortune in selling these bricks.

And so, you know, Rico, "ching, ching, ching" lifts the gate back up and--

I'm going to delete this, it's taking away from the reality here.

So it lifts the gate back up and they guy still standing there a day later

and going "I still need my 210 bricks", and so Rico now equipped

with flags from Bob's handy store idea.

Rico just watch around and put flags into the piles that need it.

So Rico goes, "Okay, 210 bricks.

So I'm going to put a flag in a 128 pile."

It's the most efficient to take the biggest first, right?

So 210 minus 128 that's the 1, 0, there will be 2, 1--

by the way, stop the story train right there.

Cicso exams, no calculator my friend.

So yes, you will have to practice some math skills beforehand.

And now, you know, of course as I'm recording this.

I've got to say, you know, in teaching ICND I've made plenty of my own mathematical errors.

So if I make one I'm sure I'll review this later and find it.

So 82, we still have more so let's put a flag in the 64 bricks so it will be 8, 7, 2, 8.

There'd be 18 leftover, okay, no 32s, okay, 16, I got to put a flag in there, right?

Are you getting how this is going?

So, okay, 2 bricks, no 8, no 4, we've got a 2, flag in the 2 minus 2-- 0, done.

Order fulfilled, okay, "Bob, do your thing."

Bob has his forklift, he wheels this out and customer A is satisfied, right!

So, what this is, is actually how binary works for numbers.

How computer applies binary to numbers behind the scene.

And so-- now keep in mind, when you're talking about--

let's just talk of computer or a router or anything.

It's doing everything in binary.

I mean, you move your mouse and binary things are happening behind the scene.

You open the Internet Explorer or Chrome or Firefox,

and binary things are happening behind the scenes.

It's always doing that, so there's ways--

so there's ways to apply numbers or binary to all kinds of things.

I can apply binary to pixels on a monitor and what color they are, how large they are,

how many of them there are, you know.

So you can apply binary to operations on a computer like saving a file to the hard drive.

Where is that file stored?

How is that file written?

You know, all of those kinds of thing.

So I'm just talking about one application of binary when a computer processes numbers,

this is what's happening behind the scenes.

Wherever you see a flag in this, this actually represents on or one,

wherever you don't see a flag, it represents the zero.

So using eight bits, this is how we will process numbers.

We'll say 0 through 255, so the number 210 in actuality,

the way the computer sees it is 11010010.

We see 210, computer sees 11010010, that's eight bits, eight binary numbers.

Okay, let's try another one.

Okay, so next customer, customer B comes up and says, "Okay, I want 120 bricks."

Okay, now Rico got his flags in order and I guess I-- didn't think about flag removal.

So we'll just grab these guys, okay there we go.

Oh man, I'm just taking out piles left and right.

So, you guys got the concept, right?

So, okay there really was not pallets or piles of bricks, it's just an analogy but it works.

Okay, so I'm going to have-- let's do 120.

Flag, got not flag in 128, okay.

Flag in 64, so let's subtract 64, 1, that'd be 6, 1, that'd be 0, 11, 5,

56 left over right-- 32, 32 minus 4, 2, 24 okay.

16, is all lining up.

So it's 16, that'd be 2, 1, 14, minus 6, 8, right?

Yup. So 8 leftover, flag right there, 8 equal to 0, so all the rest goes to 0.

So when we come to 120, this in binary is actually 0.

We don't take off the leading zeroes because we're really kind of been

in a fixed at least with the IP version 4.

Every octet is eight bits, so we're stuck with these eight bits.

So we're going to go 01111000.

Is that right?

That's eight bits, right?

So that's our eight bits that put those together, okay?

So we see 120, computers, routers, everything else sees 00111000.

Now before we figure out the short angry man and his 15 bricks.

I want to go back to the values themselves, because I know some

of you more analytical people might be thinking, well, I'm seeing how this works,

I get the system but where do these numbers come from?

Like why do they get 64 or 16?

I mean, I kind of see, you know, I multiply by 2 to them, right?

Well, yes.

When the powers had been figured out how devices process numbers, they said, "Well,

what we'll do is we'll make the binary values represent powers of 2."

So 2 to the power of zero is actually 1.

Anything to the power of 0 is 1.

I don't know exactly why that is.

I know anything times 0 is 0 but anything to the power of 0 is really one.

So we move over and we go, okay, well the next one is actually 2 to the power of 1, so one 2.

So we go to the next one we have two 2s.

2 to the power of 2, 2 times 2 is 4.

2 to the power of 3 is the number 8.

Now it will be good-- I'm showing this to you because it will be good for you to know this

when we get into some of the more advanced subnetting knowing that these are just powers

of 2 will kind of give you a shortcut in some cases.

So, really, if we're trying to generate this, you know, frankly, I never remember.

If I look at 128, I don't think 2 to the power of 7, it doesn't pop into my head right away.

If I forget these numbers and I just say "Okay, we'll start from one and just multiply by 2."

1 times 2 is 2, times 2 is 4, times 2 is 8, yeah I mean, and comeback and fill

in the powers of 2 a little bit later.

But I just want to show you behind the scenes, that's how the computer actually does it.

So let's look at angry man 15 bricks.

I want my 15-- I look up-- I'll just keep the flags there so-- for time's sake.

So I'm going to say 15, let's go no 128s, no 64s, no 32s, no 16s,

so all of these are 0s to start off, one 8.

So 15 minus 8 that leaves you with 7, right?

So 14 that leaves with 4.

So you notice I always start from the left to right.

I'm always trying to take the biggest value from something.

So I've got 3, so that's 1, 1.

A 2 and a 1 equals 3 so I'm always going to get to zero at the very end.

So 15 as I binary value is 0000111.

Okay, so these skills that we're going through, binaries, subnetting, they're all skills

that you can watch somebody do and go, "Oh, okay, I get that."

But until you do it for yourself it won't actually stick with you, you know, when--

or when it comes time to do it, you're like, "Oh!'

Now how did that go?

So for these next sections, I'm going to have some homework for you,

stuff to work on your own, so you're able to master the skill.

So here's what I'd like you to do.

Pause this nugget right now, well, after I finish talking.

Pause this nugget and work through these five.

If you don't get number five, that's okay, that's my challenge question.

Work through these five and see if you can get them, and then unpause

and I'll work through them with you, okay?

So pause now.

Okay, welcome back.

So we've got 180 to binary.

Let's look at that.

Whenever you do this, it's all-- I mean you got to give yourself the grid to work from,

write those values on the piece of paper or whatever you're working with.

So I've got 18 or 128, 64, 32, 16, 8, 4, 2, 1 if you need to write them right to left to multiple

by two that's fine, until you master them.

But trust me you will get these numbers down.

You will remember them.

So let's look at 18 to the binary.

What we do is always start with the biggest value.

So 180 minus and I'll go okay, 128.

I can subtract 128 from there, 128 that equals 7, 252 leftover.

Okay, can't take a 64 so I'm going to write a zero there.

32, yes, so I'll put 32 minus equals 20.

16, I can take 16 from 20.

16 minus equals 4.

So no wait, it's definitely 1400.

I can just fill those in 'cause 4 is going to zero us out.

So 180 in binary is actually 10110100.

Did you get it?

Cool. That's my first time actually using this eraser in my pen, pretty cool.

Okay, so I've got 118.

Okay, let's look at 41.

So 41 in binary I can immediately say, okay, no, no too big.

132 let subtract that.

That will be 9 leftover.

So no, yes and no, no, yes.

So 41 is 00101001.

All right, good.

Now, I kind of flip the game on you as we're-- what we're talking.

I haven't given you example of this yet.

I just want to see if you can kind of reason through it and say, "Okay,

if somebody gave me a binary number can I convert that back to decimal?"

How would I do that?

Well, really you just line it up.

It's that, you know, it's little more math and subtraction, but I say, okay, well,

let's line it up to the binary or the decimal values

above 110 and then just do some additions.

So I'll go okay, 32 really is 32 plus 16 plus 4 plus 2 will give me my decimal number.

So let's start here.

And so, 8 and 48, right?

And then, add 8 in there, so-- wait no.

It's so easy to make a mistake when I'm talking.

So add 6 in there, right?

4 plus 2. So we've got 54.

So 00110110, what I'm doing?

No, the decimal value of that binary number is 54, right?

So that's the decimal okay.

Next one. 100, so my cellphone I have it on buzz mode.

It goes bzzz behind the scenes and immediately my brain is like what's that?

What's that?

What's that?

And so, I stop thinking.

Okay, so 0-- 1001, all right, 0110.

Okay, so adding those up, so I've got 128.

I always look around for easy math, 'cause I'm not that greatest at it.

So I go, okay.

Well, 16 plus 4 that's 20, right?

So 20 plus 128 that be 148 plus 2 that's 150.

So you can jump around like that.

I mean you don't have to add them in order, right?

You know, you're adding it doesn't matter what order you're going in.

So I was trying to find the nice even values that go

in the increments of 10 for people like me.

Okay, so that will be-- that one in decimal.

Okay, now let's look at the challenge question, right?

All right, [inaudible] off there.

Challenge question says, converts 650 into binary.

Now, the challenge about this is we haven't see anything like it, because with these values

that are on the board right now, I can't get any higher than 255.

With 8 bits I can't go higher than that.

So to get 650, I actually have to go beyond 8 binary bits.

It's that simple.

So what I do is I said, "Okay.

Well, let's multiply by 2.

If I multiply 128 by 2, I get 256.

I multiplied 256 by 2 I get 512.

You might be saying, how you do it?

I've just seen these values, so often that it just you get used to them.

But if you need to, you know, write up a quick multiplication question, it's no problem.

So if I multiply-- you know, I still look, "I'm okay, 512 smaller than 650,

so I multiply that by 2 and I get 1024.

Now be careful, because when you're looking, you go, "Okay, well, okay 1024 is bigger,

so that's what I put a one by, right?

No, remember we always subtract whatever we can subtract.

I can't subtract 1024 from 650 without getting a negative number.

So essentially I look at that and go, okay, that's too big.

That's not going to-- I'm not going to do anything for it.

So I look at 512 and say, okay, that's the first value that I can subtract.

So 650 minus 512 gives me to be 6-- well, actually let me, 5, 4 that'll be 10, 8, so 3, 1,

right, 'cause I should have marked through the-- is that right?

138, yeah!

Okay, so 138, 256, nope you can't take that away.

Okay, 128 that's good, 'cause that gives me a nice small value to work with.

So I go down to 10.

I go okay, great.

0001010, right?

So 8 and 2 is that 10 that I'm looking for.

So that's gives me zero.

So really the binary value of 650 is 1010001010.

Good. So we went beyond the normal 8 bits that we're used to seeing with IP version 4.

Now you might look at that and go, "Okay, will I do a lot of that?"

Some, you'll do some.

I'll explain situations where you'll do that.

And when we get into the more advanced subnetting but I would say by far,

by far in IP you're going to sticking to 8 bits.

You're going to be sticking to those values.

So I would say think of going beyond that is more of an exception

like you don't do it all the time, and the bulk, the line share of what you do,

just sticks to that 8 bit boundary.

Okay, you have just taken a step into IP subnetting.

You've learned the foundational skill that you need

for everything IP subnetting that's going to be coming up.

It's a huge step.

What would I suggest you do with it?

Practice. Don't-- do not go into the next nugget until you do some more practice.

I give you five questions but that's not enough.

I would suggest that you grab a piece of paper just a white sheet of paper

and do ten more decimal to binary.

So write down just 10 numbers, you know, I would suggest keeping them 255 or less,

and then convert them over to binary to make sure that you have that.

And then, once you're done with that do five more questions on binary back to decimal,

and do that convert it to where it becomes one of those things

that you get really familiar with, and starting to feel comfortable

for you to do those kind of conversions.

Now, you can actually check your work.

If you open the Windows calculator just to start run calc or I was--

hold on the Windows key and do R, to bring up the run.

And so, you just type in calc right here or you can find it some more in the start.

And I think it's under accessories.

Now, I have mine in the programmer view.

By default most of the time it will come up like this if you haven't done this before.

In Windows XP or earlier if you are earlier you want scientific view.

In Window 7 or 8 or wherever you're at do-- jump over to programmer view.

Excuse me.

What you want is this decimal binary selector so that way you can always come in here and say,

"Oh I want the number 89" and click on binary and it says, "Well here's the binary value

for that or, you know, what is one, one, you know, what is that value, you know, in decimal.

Click that and poof it will tell you what the decimal version of that is.

Now, keep in mind, like if I do 56 and I shoot back to binary,

this does drop the leading zeros.

So, it shows, in this case six bits.

So, in the number 56 there's no 128s, there's no 64s, the first one is a 32.

So, don't-- don't let that throw you off

because the calculator does drop the leading zeros when converting to binary.

Now, the second thing I want to say right now is,

some of you are probably looking going, "Wow.

So, you're saying this could've been a five minute nugget on how

to use Windows calculator to convert to binary.

Why do I have to know this if I can use a calculator?"

Well, number on the exam I've already told you there is no calculator.

So you have to know it if you plan on getting certified.

But number two, there-- I mean this is a skill that is foundation to networking.

Like this is-- you cannot really master networking

without knowing subnetting, without being able to do that.

And I can't tell you how, how valuable it is to have that skill 'cause there's, you know,

some people, I mean, I just showed you a binary calculator.

There are complete subnet calculators out there too that you can just type in values

and it will tell you all the subnets that you need and all that.

But let me put it this way.

If you talk to somebody who does Cisco or does networking as kind of a peripheral

of their primary job function like they-- their main thing is I work in Microsoft

or I'm a programmer and I-- yeah I can do some Cisco as well.

For those people, most of the time they'll say yeah, subnetting, I use a subnet calculator,

probably just 'cause they don't deal with it enough

to really solidify the concept in their mind.

However, if you talk to somebody who does Cisco, who does networking, like this is my job.

This is what I do.

I work for a service provider.

I work in data centers regularly.

I work for a fortune 500 company that's large enough

to have a full time network person or multiple full time network.

I mean if you ask those people, can you do binary, you know, without a calculator.

Yes, can you do something?

Yes. You'll be able-- I can-- and I can't tell you how valuable it is.

I mean there's so often, I've been in a network environment so just, I'm smiling because just

as this last weekend, I was actually at a data center and we're trying to figure

out in the data center said, "Okay, we're going to be dropping your connection on 2/30 subnets.

So, it will be the network ID is, you know, I can't remember, 1850,

you know 9 or something, you know."

So they're rattling up the network ID and the guy with me, he goes,

"All right subnet was, what is it?"

And they're like, "Okay we need to assign nine over here.

We need to assign 20," you know, to where you can just kind of think through it

and process it, you know, without having to, okay, I'm not too sure, let's boot up my laptop.

Let's get, you know, it's just, it's just skills that you use all the time.

So, run through that practice, make sure you've got the binary conversion solid then jump

into the subnetting.

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