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Protocols, Lesson 2: Binary and the Internet Protocol

To understand the Internet Protocol, we need to learn and understand Binary. An important part

of IP is subnetting, which can only be explained and understood when an IP address is convertedto Binary. A lot of people are not aware that computers do not understand words, pictures and

sounds when we interact with them by playing a game, reading or drawing something on the

screen. The truth is that all computers can understand is zeros...

and ones. What we see on the screen is just an interpretation of what the computer understands,

so the information displayed is useful and meaningful to us.

Binary: Bits and bytes

To put it as simply as possible, a Bit is the smallest unit/value of Binary notation. The same way

we say 1 cent is the smallest amount of money you can have, a Bit is the same thing but in

Binary.

A Bit can have only one value, either a one or a zero. So if I gave you a value of zero (0) then

you would say that is one Bit. If I gave you two of them (00), you would say that 's two Bits.

Now, if you had eight zeros or ones together, as in 0110 1010 (I put a space in between to make

it easier for the eyes), you would say that's 8 Bits or one Byte. Yes, that is correct; eight Bits are

equal to one Byte. It doesn't matter if they are all ones or zeros or a mixture of the two.


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The picture below gives you some examples:

To sum this all up, 1024 Bytes equal 1 Kbytes (Kilobyte). Why 1024 and not 1000? Well it's

because of the way Binary works. If you did the math, you would find the above correct.

Everyone who uses the Internet would have, at one stage or another, come across the "Byte" or"Bit" term. This most frequently happens when you're downloading; you get the speed indicationin bytes or Kbytes per second. We are going to see exactly what a Bit, Byte and Kbyte is, so youunderstand the terms.

So, what's binary got to do with IP?

The above example shows an IP address in decimal notation, which we understand more easily.

This IP address (192.168.0.1) is then converted to Binary, which is what the computer

understands. You can see how big the number gets. It's easier for us to remember four different

numbers than 32 zeros or ones.


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Now, keeping in mind what we said earlier about Bits and Bytes, have you ever heard or read

people saying that an IP address is a 32 Bit address? It is, and you can now see why:

So to sum up all the above, we now know what Binary notation is, what a Bit, Byte and Kbyte is

and how Binary relates to an IP address, which is usually represented in its decimal notation.

Well, just as I explained in the introduction, computers display the zeros and ones in a way thatmakes the information useful to us. IP works a bit like this as well, where 98% of the time we seeit in a decimal notation, but the computer understands it in binary. The picture below gives youan example of how a computer understands an IP address:

Understanding the conversion between decimal and binary

The conversion is not that hard once you grasp the concept. The picture below shows an IP

address that we are going to convert to Binary. Keep in mind that the method I'm going to show

you is the same for all conversions. We are now going to convert the first octet in the IP address

192.168.0.1 to Binary/ In other words, we take the "192" and convert it to Binary. We are not

going to have to do any difficult calculations, just simple additions:
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If you have read and understood the first section of this page, you should know that we need

eight bits to create one octet or, if you like, the 192 number. Each bit takes a certain value which

never changes, and this value is shown in purple, right above the bit. We then select the bits weneed in such a way that the sum of all selected bits gives us the decimal number we need.

If you wanted to explain the conversion in mathematical terms, you would say that each bit is a

power of 2 (2^), for example, bit 8 is actually '2^7' = 128 in decimal, bit 7 is '2^6 = 64 in

decimal, bit 6 is '2^5' = 32 in decimal, bit 5 is '2^4' = 16 in decimal, bit 4 is '2^3' = 8 in decimal,

bit 3 is '2^2' = 4 in decimal, bit 2 is '2^1' = 2 in decimal, and bit 1 is '2^0' = 1 in decimal.

Note: When calculating the decimal value of an octet (192 in the example above), the Bitnumbers do NOT represent the power of two value we must use in order to get the decimal

value. This means that Bit 1 does NOT translate to 2^1=1 in decimal.

In our example, we used the 192. As you saw, we needed bits 8 and 7 and this gave us the Binary

number of 11000000, which is 192 in decimal. You must remember that the values of each bit

never change. For example, bit 8 always has a decimal value of 128, whereas bit 1 always takes

the value of 1. Using this method, you will find it easy to convert decimal to Binary without the

need for complex mathematical calculations.


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So let's have a look at the next octet, which is the decimal number 168:

Here again you can see that we needed to choose bits 8, 6 and 4 (in other words put a "1" in the

bit's position) in order to get a decimal value of 168. So the Binary value of 10101000 is equal tothe decimal value of 168.

Let's now look at all 4 octets of our IP address, in Binary:

No matter which way you convert, from Decimal to Binary or Binary to Decimal, the same

method is used. If you understood the above, you should be able to convert any Binary or

Decimal number.


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That just about does it for this section; you're now ready for the next section!

Protocols, Lesson 3: The Internet Protocol header

Introduction

When a computer receives a packet from the network, the computer will first check the

destination MAC address of the packet at the Datalink Layer (2). If it passes, it's then passed on

to the Network layer.

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At the Network layer, it will check the packet to see if the destination IP address matches the

computer's IP address. (If the packet is a broadcast, it will pass the network layer anyway.)

From there, the packet is processed as required by the upper layers.

On the other hand, the computer may be generating a packet to send to the network. Then, as the

packet travels down the OSI model and reaches the Network layer, the destination and source IP

address of this packet are added in the IP header.

Just like every other protocol, IP has a place in the OSI model. Because it's such an important protocol and other protocols depend upon it, IP needs to be placed before them in the OSI model.That's why you will find it in Layer 3:

The IP header


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It's worth noting that the 9th field, which is the "Protocol" field, contains some importantinformation that the computer uses to find out where it must pass the datagram once it strips off

the IP header.

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If you remember, TCP and UDP exist on Layer 4 of the OSI Model, which is the transport layer.

When data arrives at a computer and the packet is processed by each layer, it needs to know

whereabouts above to pass the data. This protocol field tells the computer to give the remaining

data to either the TCP or UDP protocol, which is directly above it.


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The destination IP address is another important field which contains the IP address of the

destination machine.

The next section talks about the five different classes of IP address

Protocols, Lesson 4: Internet Protocol classes - Network and host ID

Introduction

Every protocol suite defines some type of addressing that identifies computers and networks. IP

addresses are no exception to this rule. There are certain values that an IP address can take; these

have been defined by the IEEE committee.



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A simple IP address is a lot more than just a number. It tells us the network of which the

workstation is part and the node ID.

IP address classes and structure

When the IEEE committee sat down to sort out the range of numbers that were going to be used

by all computers, they came up with five different ranges or, as we call them, "classes" of IP

addresses. When someone applies for IP addresses they are given a certain range within a

specific class depending on the size of their network. To keep things as simple as possible, let's

first have a look at the five different classes:


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In the above table, you can see the five classes. Our first class is A and our last is E. The first

three classes (A, B and C) are used to identify workstations, routers, switches and other devices,

whereas the last two classes (D and E) are reserved for special use.

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An IP address consists of 32 Bits, which means it's four Bytes long. The first octet (first eight

bits or first byte) of an IP address is enough for us to determine the class to which it belongs.And, depending on the class to which the IP address belongs, we can determine which portion of

the IP address is the network ID and which is the node ID.

For example, if I told you that the first octet of an IP address is "168," then, using the above

table, you would notice that it falls within the 128-191 range, which makes it a class B IP

address.

Understanding the classes

We are now going to take a closer look at the five classes. Earlier I mentioned that companies are

assigned different IP ranges within these classes, depending on the size of their network. For

instance, if a company required 1000 IP addresses, it would probably be assigned a range that

falls within a class B network rather than a class A or C.


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The class A IP addresses were designed for large networks, class B for medium size networks

and class C for smaller networks.

Introducing network ID and node ID concepts

We need to understand the network ID and node ID concept because it will help us to fully

understand why classes exist. Putting it as simply as possible, an IP address gives us two pieces

of valuable information:

1) It tells us which network the device is part of (network ID).

2) It identifies that unique device within the network (node ID).

Think of the network ID as the suburb you live in and the node ID as your street in that suburb.

You can tell exactly where someone is if you have their suburb and street name. In the same

way, the network ID tells us to which network a particular computer belongs and the node ID

identifies that computer from all the rest that reside in the same network.

The picture below gives you a small example to help you understand the concept: Explanation:


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In the above picture, you can see a small network. We have assigned a class C IP range for this

network. Remember that class C IP addresses are for small networks. Looking now at Host A,

you will see that its IP address is 192.168.0.2. The network ID portion of this IP address is in

blue, while the host ID is in orange.

I suppose the next question someone would ask is: How do I figure out which portion of the IPaddress is the network ID and which is the host ID?

That's what we are going to answer next.

The network and node ID of each class

The network class helps us determine how the four byte, or 32 bit, IP address is divided between

network and node portions.

The table below shows you (in binary) how the Network ID and Node ID changes depending on

the class:


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Explanation:

The table above might seem confusing at first but it's actually very simple. We will take class A

as an example and analyze it so you can understand exactly what is happening here:

Any class A network has a total of 7 bits for the Network ID (bit 8 is always set to 0) and 24 bits

for the Host ID. Now all we need to do is calculate how much seven bits is:

2 to the power of 7 = 128 networks and for the hosts : 2 to the power of 24 = 16,777,216 hosts in

each network, of which two cannot be used because one is the Network Address and the other is

the network broadcast address (see the table towards the end of this page). This is why when we

calculate the "valid" hosts in a network we always subtract "2". So if I asked you how many

"valid" hosts can you have a on class A network, you should answer 16,777,214 and NOT

16,777,216.

Below you can see all this in one picture:


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The same story applies for the other two classes we use, that's class B and class C, the only

difference is that the number of networks and hosts changes because the bits assigned to them are

different for each class.

Class B networks have 14 bits for the network ID (Bits 15, 16 are set and can't be changed) and

16 bits for the host ID, that means you can have up to '2 to the power of 14' = 16,384 networks

and '2 to the power of 16' = 65,536 hosts in each network, of which two cannot be used because

one is the network address and the other is the network broadcast address (see the table towardsthe end of this page). So if I asked you how many "valid" hosts can you have on class B network,

you should answer 65,534 and NOT 65,536.


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Class C networks have 21 bits for the network ID (Bits 22, 23, 24 are set and can't be changed)

and eight bits for the host ID, that means you can have up to '2 to the power of 21' = 2,097,152

Networks and '2 to the power of 8' = 256 hosts in each network, of which two cannot be used

because one is the network address and the other is the network broadcast address (see the table

towards the end of this page). So if I asked you how many "valid" hosts you can have on class C

network, you should answer 254 and NOT 256.

Now, even though we have three classes of IP addresses that we can use, there are some IPaddresses that have been reserved for special use. This doesn't mean you can't assign them to a

workstation but in the case that you did, it would create serious problems within your network.

For this reason it's best to avoid using these IP addresses.

The following table shows the IP addresses that you should avoid using:

IP address Function

Network 0.0.0.0 Refers to the default route. This route is to simplify routing tables


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used by IP.

Network 127.0.0.0 Reserved for Loopback. The Address 127.0.0.1 is often used to

refer to the local host. Using this Address, applications can address

a local host as if it were a remote host.

IP Address withall host bits set to

"0" (Network

Address) e.g.

192.168.0.0

Refers to the actual network itself. For example, network192.168.0.0 can be used to identify network 192.168. This type of

notation is often used within routing tables.

IP Address with all

node bits set to "1"(Subnet / Network

Broadcast) e.g.

192.168.255.255

IP Addresses with all node bits set to "1" are local network

broadcast addresses and must NOT be used.

Some examples: 125.255.255.255 (Class A), 190.30.255.255

(Class B), 203.31.218.255 (Class C). See "Multicasts" &

"Broadcasts" for more info.

IP Address with all

bits set to "1"

(Network

Broadcast) e.g.

255.255.255.255

The IP Address with all bits set to "1" is a broadcast address and

must NOT be used. These are destined for all nodes on a network,

no matter what IP address they might have.
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Now make sure you keep to the above guidelines because you're going to bump into a lot of

problems if you don't!

IMPORTANT NOTE: It is imperative that every network, regardless of Class and size, has a

Network Address (first IP address e.g. 192.168.0.0 for Class C network) and a Broadcast

Address (last IP address e.g. 192.168.0.255 for Class C network), as mentioned in the table and

explanation diagrams above, which cannot be used.

So when calculating available IP addresses in a network, always remember to subtract 2 fromthe number of IP addresses within that network.

That all pretty much covers this section.

Next, is the subnetting section, and before you proceed, make sure you're comfortable with the

new concepts and material we have covered, otherwise subnetting will be very hard tounderstand.

Protocols, Lesson 5: Introduction to subnetting

What is subnetting?

When we subnet a network, we basically split it into smaller networks. For example, when a set

of IP addresses is given to a company, the company might want to "break" (the correct term is

"partition") that one network into smaller ones, one for each department. This way, the technical

department and management department can each have a small network of their own. By

subnetting the network, we can partition it to as many smaller networks


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as we need. This also helps reduce traffic and hides the complexity of the network.

By default, all type of classes (A, B and C) have a subnet mask; we call it the default subnet

mask. You need to have one because:

1) All computers need the subnet mask field filled when configuring IP

2) You need to set some logical boundaries in your network

3) You should at least enter the default subnet mask for the class you're using

In the previous pages I spoke about IP classes, network IDs and host IDs. The subnet mask is

what determines the network ID and host ID portion of an IP address.

The table below shows clearly the subnet mask that applies for each network class.

When dealing with subnet masks in the real world, we are free in most cases to use any type of

subnet mask in order to meet our needs. If, for example, we require one network which can

contain up to 254 computers, then a class C network with its default subnet mask will do fine. If

we need more, then we might consider a class B network with its default subnet mask.

Note that the default subnet masks have been set by the IEEE committee, the same guys that set

and approve the different standards and protocols.

We will have a closer look at this later on and see how we can achieve a class C network with

more than 254 hosts.

Understanding the concept


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Let's stop here for one moment and have a look at what I mean by partitioning one network into

smaller ones by using different subnet masks.

The picture below shows our example network (192.168.0.0). All computers here have been

configured with the default class C subnet mask (255.255.255.0):

Because of the subnet mask we used, all these computers are part of the one network marked in

blue. This also means that any one of these hosts (computers, router and server) can

communicate with each other.

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If we now wanted to partition this network into smaller segments, then we would need to change

the subnet mask appropriately so we can get the desired result. Let's say we needed to change the

subnet mask from 255.255.255.0 to 255.255.255.224 on each configured host.

The picture below shows us how the computers will see the network once the subnet mask has

changed:

In reality, we have just created eight networks from the one large (blue) network we had, but I

am keeping things simple for now and showing only two of these smaller networks because I

want you to understand the concept of subnetting and see how important the subnet mask is.

In the following pages we'll analyze in great depth the way subnetting works and how to

calculate it. It is very important that you understand the concepts introduced in this section, so

make sure you do, before continuing


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The effect of a subnet mask on an IP address

In the IP classes page we analyzed and showed how an IP address consists of two parts, 1) The

network ID and 2) The host ID. This rule applies for all IP addresses that use the default subnetmask, so we call them classful IP addresses.

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We can see this once again in the picture below, where the IP address is analyzed in binary,

because this is the way you should work when dealing with subnet masks:
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We are looking at an IP address with its subnet mask for the first time. What we have done is

take the decimal subnet mask and converted it to binary, along with the IP address. It is essential

to work in binary because it makes things clearer and we can avoid making silly mistakes. The

ones (1) in the subnet mask "lock" or, if you like, define the network ID portion. If we change

any bit within the network ID of the IP address, then we immediately move to a different

network. So in this example, we have a 24 bit subnet mask.

NOTE:

All class C classful IP addresses have a 24 bit subnet mask (255.255.255.0).

All class B classful IP addresses have a 16 bit subnet mask (255.255.0.0).

All class A classful IP addresses have an 8 bit subnet mask (255.0.0.0).

On the other hand, the use of an IP address with a subnet mask other than the default results inthe standard host bits (the Bits used to identify the HOST ID) being divided in to two parts: a

subnet ID and Host ID. These types of IP addresses are called classless IP addresses.

In order to understand what a "classless IP address" is without getting confused, we are going to

take the same IP address as above, and make it a classless IP address by changing the default


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subnet mask:

Looking at the picture above you will now notice that we have a subnet ID, something that didn't

exist before. As the picture explains, we have borrowed three bits from the host ID and used

them to create a subnet ID. Effectively we partitioned our class C network into smaller networks.

If you're wondering how many smaller networks, you'll find the answer on the next page. I prefer

that you understanding everything here rather than blasting you with more subnet ID's, bits and

all the rest :)

Summary

In this page we saw the default subnet mask of each class and also introduced the classful and

classless IP addresses, which are a result of using various subnet masks.

When we use IP addresses with their default subnet masks, e.g. 192.168.0.10 is a class C IP

address so the default subnet mask would be 255.255.255.0, then these are "classful IP

addresses."

On the other hand, classless IP addresses have their subnet mask modified in a way so that there

is a "subnet ID". This subnet ID is created by borrowing bits from the host ID portion.


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The picture below shows us both examples:

I hope that you have understood the new concepts and material on this page. Next we are going

to talk about subnet bits, learn how to calculate how many bits certain subnet masks are and see

the different and most used subnet masks available

Protocols, Lesson 8: Subnetting analysis

We have already covered subnetting in some depth, but there is still much to learn. We are going

to explain the available subnet masks and analyze a class C network using a specific subnetmask. It's all pretty simple, as long as you understand the logic behind it.



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Understanding and analyzing different subnet masks


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You cannot take any subnet mask you like and apply it to a computer or any other device,

because depending on the random subnet mask you choose, it will either create a lot of routing

and communication problems, or it won't be accepted at all by the device you're trying to

configure.

For this reason, we'll look at the various subnet masks so you know exactly what you need to

use, and how to use it. Most important, we are going to make sure we understand WHY you need

to choose specific subnet masks depending on your needs. Most people simply use a standard

subnet mask without understanding what that does. This is not the case for the visitors to this

site.

Let's first have a look at the most common subnet masks, and then I'll show you where thenumbers come from:

OK, so we know what a subnet mask is, but we haven't spoken (yet) about the different valuesthey take, and the guidelines we need when we use them. That's what we are going to do here.

Common subnet masks

Numer of bits Class A Class B Class C

0 (default

mask)

255.0.0.0

(default_mask)

255.255.0.0

(default_mask)

255.255.255.0

(default_mask)

1 255.128.0.0

(default+1)

255.255.128.0

(default+1)

255.255.255.128(default+1)


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2 255.192.0.0

(default+2)

255.255.192.0

(default+2)

255.255.255.192(default+2)

3 255.224.0.0

(default+3)

255.255.224.0

(default+3)

255.255.255.224(default+3)

4 255.240.0.0

(default+4)

255.255.240.0

(default+4)

255.255.255.240(default+4)

5 255.248.0.0

(default+5)

255.255.248.0

(default+5)

255.255.255.248(default+5)

6 255.252.0.0

(default+6)

255.255.252.0

(default+6)

255.255.255.252(default+6)

7 255.254.0.0

(default+7)

255.255.254.0

(default+7)

255.255.255.254(default+7)

* Only 1 Host per subnet

8 255.255.0.0

(default+8)

255.255.255.0

(default+8)

255.255.255.255(default+8)

* Reserved for Broadcasts

The above table might seem confusing at first, but don't despair! It's simple; really, you just need

to look at it in a different way!


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Now, that was the easy part. The second part is slightly more complicated and I need you

focused so you don't get mixed up!

At first the diagram below seems quite complex, so try to follow me as we go through it:

The IP address and subnet mask is show in binary format. We focus on the last octet which

contains all the information we are after. Now, the last octet has two parts, the subnet ID and

host ID. When we want to calculate the subnets and hosts, we deal with them one at a time. Once

that's done, we put the subnet ID and host ID portion together so we can get the last octet's

decimal number.

We know we have eight networks (or subnets) and, by simply counting or incrementing our

binary value by one each time, we get to see all the networks available. So we start off with 000

and finish at 111. On the right hand side I have also put the equivalent decimal number for each

network.


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Next we take the host ID portion, where the first available host is 0 0001 (1 in Decimal), because

the 0 0000 (0 in Decimal) value is reserved as it is the network address (see IP classes page), and

the last value which is 1 1111 (31 in decimal) is used as a broadcast address for each subnet (see

Broadcast page).

Note:

I've given a formula in the IP classes page that allows you to calculate the available hosts, that's

exactly what we are doing here for each subnet. This formula is :2 to the power of X -2. Where X

is the number of bits we have in the host ID field, which for our example is 5. When we apply

this formula, we get 2 to the power of 5 - 2 = 30 Valid (usable) IP addresses. If you're wondering

why we subtract 2, it's because one is used for the Network Address of that subnet and the other

for the Broadcast Address of that subnet. This shouldn't be new news to anyone :)

Summing up, these are the ranges for each subnet in our new network:


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I hope the example didn't confuse you too much; the above example is one of the simplest type,

which is why I chose a class C network, they are the easiest to work with.

Protocols, Lesson 9: Subnet routing and communications

Communication between subnets

After reading all the previous pages about subnetting, let me ask you the following:

Do you think computers that are on the same physical network but configured to be on separate

subnets are able to communicate?

The answer is "no". Why? Simply because you must keep in mind that we are talking about the

communication between two different networks!


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Looking at our example of the class C network on the previous page, the fact is that one

computer is part of the network 192.168.0.0 and the other one part of network 192.168.0.32, and

these are two different networks. In our example, from the moment we modified the default

subnet mask from 255.255.255.0 to 255.255.255.224, we split that one network to 8 smaller

ones.

Let's try it

And because we just have to prove it, we are going to try it on my home network. In the worst

case I'll have to spend all night trying to figure out what went wrong, but it will be worth it!

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Without complicating things, here is a diagram of my home network. (I've excluded any

computers we are not going to be using, in order to save space.)
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That's the network we have to play with. I have put on the diagram the results of a few simple

pings from each host and, as you can see, they all came out nice: PASS.

In order to proceed to phase two of our experiment, I modified the subnet mask of my

workstation to 192.168.0.35 / 255.255.255.224 , my Slackware Linux Firewall to 192.168.0.1 /

255.255.255.224 (internal Network Interface Card) and my NetWare 6 server to 192.168.0.10 /

255.255.255.224 as shown in the diagram below:


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therefore can communicate with my workstation. On the other hand the NetWare server now acts

as a gateway for network 1, so my workstation is reconfigured to use it as its gateway. Any

packets from network 1 to network 2 or the Internet will pass through the NetWare server

Method 2: Binding 2 IP addresses to the same network card

This method is possibly the best and easiest way around our problem. We use the same network

card on the NetWare server and bind another IP address to it.

This second IP address will obviously fall within the network 1 IP range so that my workstation

can communicate with the server:

As noted on the diagram, the only problem we might encounter is the need for the operatingsystem of the server to support this type of configuration, but most modern operating systems

would comply.

Once configured, the server takes care of any routing between the two networks.


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Method 3: Installing a router

The third method is to install a router in the network.

This might seem a bit far fetched but remember that we are looking at all possible ways to

establish communications between our networks! If this was a large network, then a router could

possibly be the ideal solution, but given the size of my network, well... let's just say it would be a

silly idea :)

My workstation in this setup would forward all packets to its gateway, which is the router's

interface and is connected to network 1 and it will be able to see all other servers and access the

Internet. It's a similar setup to Method 1 but instead of a server we have a dedicated router. Oh,and by the way, if we would end up using such a configuration in real life.. the hub which both

of the router's interfaces connects to would be replaced by some type of WAN link.

That completes our discussion on Subnet routing and communication


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Protocols, Lesson 10: Subnetting guidelines

The number of problems that can occur in a network are numerous, and -- believe it or not --

most of them can be avoided if the initial design and installation of the network are done properly.



Continue Reading

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When I say "done properly," I don't just mean connecting the correct wires into the wall sockets.

Looking at it from an administrator's point of view, I'd say that a properly done job is one that

has had a lot of thought put into it to avoid silly routing problems and meet today's and any

future needs.

This page contains all the information you need to know in order to design a network that won't

suffer from any of the above problems. You would be amazed at how frequently I see networks

suffering from all the above at large companies.

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Calculate the maximum number of subnets required by rounding up the maximum number to thenearest power of two. For example, if an organization needs five subnets, 2 to the power of 2 or 4will not provide enough subnet addressing space, so you must round up to 2 to the power of 3 =8 subnets.

You must plan for future growth. For example, if 9 subnets are required today, and you choose to provide for 2 to the power of 4 = 16 subnets, this might not be enough when the seventeenthsubnet needs to be deployed. In this example, it might be wise to provide for more growth andselect 2 to the power of 5 = 32 as the maximum number of subnets.

You must ensure that there are enough bits available to assign host addresses to theorganization's largest subnet. If the largest subnet needs to support 40 host addresses today, 2 tothe power of 5 = 32 will not provide enough host address space, so you would need to round upto 2 to the power of 6 = 64.

Besides planning for additional subnets, you must also plan for more hosts to be added to eachsubnet in the future. Make sure the organization's address allocation provides enough bits todeploy the required subnet addressing plan.

When developing subnets, class C addresses present the greatest challenge because fewer bits are

available to divide between subnet addresses and host addresses. If you accommodate too many

subnets, there may be no room for additional hosts and growth in the future.

All the above points will help you succeed in creating a well designed network which will have

the ability to cater for any additional future requirements.

protocols lesson

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