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I'm going to talk about IP addresses in a lot of detail later.

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But let's look at an example on this phone and you'll be able to do something similar on an Android

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device or Windows PC and so forth.

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I'm going to go to settings.

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I'm going to look at the information about my wireless network and what I can see here is that my IP

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address was configured automatically.

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Basically a server allocated an IP address to my phone.

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That's very typical of network so using what's called DHCP or Dynamic Host Configuration Protocol a

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server allocates an IP address to your device.

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In this example, my IP address on the phone is 192.168.172

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Now that is a 4 octet IP address IPv4 octet 8 binary values.

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Hopefully, it makes a bit more sense now 192 in decimal equates to 1100 followed by 4 0s.

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So 11 and 6 binary 0s is the equivalent of 192 in decimal.

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So we've got an 8 bit binary number 192 followed by a dot followed by another 8 bit binary number.

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In this example 168 followed by another number 1 followed by the last number 72, 4 octets or 4 binary

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each gives us an IPv4 address with the length of 32 bits, 8 plus 8 plus 8 plus 8 32

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bits in binary.

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So 192 is an 8-bit binary number which equates to 1 1 followed by 6 0s.

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We could do something similar for 168.

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We could work out what that is in binary. 1 is fairly simple it's 7 binary 0s followed by a

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binary one gives me decimal 1 and then we've got 72.

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We've also got a subnet mask subnet masks become very important to determine if our host is on the same

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subnet as you.

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We'll talk about that in more detail in the subnetting section but hopefully, now you can recognize 255

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255 is eight binary ones so you've got eight binary ones 255 and another eight binary ones 255 third

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255 is equivalent to eight binary ones.

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And then we've got eight binary zeros 32 that subnet mask once again.

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So for octet or for groupings if you like of binary ones and zeros which are eight bits in size then

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we've got a default gateway 1 9 2 1 6 8 1 249.

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That is an example of an IP version for dress with its subnet mask and default gateway.

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In this example on my phone you could do something similar on a computer.

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So in my example I could go to my wireless connection on my P.C. open network preferences and what I

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can see here is my Wi-Fi connection on this laptop or MacBook in this case has an IP address of 10 0

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0 2.

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If I go to advanced DCP IP PCV IP is the protocol that we're using IP version 4 is the IP version that

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we're using here we can see IP addresses 10 0 0 2 subnet mask 255 255 255 0 Rodda is 10 0 0 1 IP version

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4 address is an address used to uniquely identify a device on an IP version for network we have what

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are called IP version for addresses which would look something like this and then we have IP version

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6 addresses don't worry about this at the moment but we could have an IP version 6 address that looks

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something like this so we won't worry about HPV 6 for the moment.

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My provision for is for --.

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In other words four times eight.

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That's an IP version 4 dress so each value in octet is 8 bits.

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Or as an analogy once again 8 cables in the range 0 to 255.

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So if we looked at 10 as an IP address 10 looks like this and I'll explain that in more detail in a

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moment.

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129 looks like this.

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Sixteen looks like this.

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And 123 looks like this.

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We can write the IP address as a decimal IP address a dotted decimal.

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That's the most common way to write it but devices use binary.

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When you create an access list or do something where you need to permit or deny traffic you're going

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to want to think in binary.

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Have a look at the binary to understand what's going on.

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Devices such as Rodders and firewalls use binary to determine what's permitted or denied.

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Okay so here's our example.

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We've got 10.

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Are you able to work out why it equals this.

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Again pause the video if you want more time to work it out for yourself.

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But here's the answer.

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Using our table this is what the binary number looks like for zeros followed by one followed by binary

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zero followed by one followed by binary zero.

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Now to get to 10 10 minus 128 would be a negative number.

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So it wouldn't be this minus 64 is a negative number.

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Wouldn't be that wouldn't be that wouldn't be that but 10 minus eight gives us two so eight plus two

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like that equals ten which means we set this bit on and this but on.

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Remember this is equal to two to the power of three.

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So two states three cables equals eight.

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Yeah we've got two states one cable.

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Decimal equivalent is two.

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So this in binary is equal to 10 in decimal.

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Now I'm hoping that makes sense.

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I going to do a few more examples now.

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So we're going to look at one twenty nine as an example.

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If you want a whole bunch of examples have a look at those quiz questions that I have on my website

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but feel free to ask questions if you struggling or if you need me to explain this a different way.

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So looking at 129 129 minus 128 gives us 1.

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So this slide is actually wrong.

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This should be a zero because one hundred and twenty nine minus 128 gives us 1.

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It doesn't allow us to minus 64 and still have a positive number.

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So 128 plus one equals 129.

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So this slide is actually wrong.

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Let me update it right now because that should be 1 followed by six zeros and a 1 and this should be

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1 followed by six zeros and a 1 128 plus one equals 129 definitely not plus 64.

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Okay so that looks better 128 plus one equals 129.

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So that's the binary equivalent of 129 nine.

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You could always use a calculator once again to check your work.

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So 129 in decimal equals that in binary in the exam once again you don't have access to a calculator

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so you'll need to know this stuff.

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Sixteen is fairly easy.

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Sixteen is just this binary but so that's what sixteen looks like in binary.

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That's what it looks like in decimal.

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And then we've got 123 now 123 minus 128 would be less than zero so it's not equal to that but 123 minus

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64 equals fifty nine.

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So in other words we'll set this value on fifty nine minus thirty two equals twenty seven so that that

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will be set on twenty seven is greater than sixteen so we'll set this button on twenty seven minus sixteen

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gives us eleven that's greater than eight so we'll set this but on eleven minus eight gives us three

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three minus four is a negative number so that but to set off but three minus two equals one so that

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but set on and so is this but to give us zero.

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So 123 looks like that in binary it's sixty four plus thirty two plus sixteen plus a plus two plus one

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equals 123 binary value a decimal value I don't know how easy you found that a lot of this depends on

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how good your basic arithmetic is that's obviously a lot easier and that's a lot easier than working

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out 123 but the principle applies same principle applies Okay so if you want some unlimited tests you

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can go to David Bumble dot com and go to free quizzes there's a binary two decimal quiz as well as a

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decimal to binary quiz these are unlimited quizzes they'll just ask you over and over again what are

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the values all Okay so that wraps up the binary section I've added some quizzes to the course but once

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again you could use those online quizzes if you prefer it's important that you know how to work with

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binary it can be quite boring but it's a fundamental building block that you need to know to be able

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to work in the real world as well as pass the CCMA exam.