IP Subneting and Bassic network fundamental.pptx

Anand Singh
AG3 - LKO
IP Subneting and Bassic network fundamental
Present By :-

INDEX
Introduction
Understanding IP Addresses
Network Masks
Understanding Subnetting
• Describe the function and operation of a hub, a switch and a router
• Describe the function and operation of a firewall and a gateway
• Describe the function and operation of Layer 2 switching, Layer 3 switching, and routing
• Identify the layers of the OSI model

Introduction---
This document will give you basic information you will need to configure your
router for routing IP, such as how addresses are broken down and how subnetting
works.
You will learn how to assign each interface on the router an IP address with a
unique subnet.

Understanding IP Addresses---
An IP address is an address used to uniquely identify a device on an IP
network. The address is made up of 32 binary bits which can be divisible into a
network portion and host portion with the help of a subnet mask. The 32
binary bits are broken into four octets (1 octet = 8 bits). Each octet is converted
to decimal and separated by a period (dot). For this reason, an IP address is said
to be expressed in dotted decimal format (for example, 172.16.81.100). The
value in each octet ranges from 0 to 255 decimal, or 00000000 − 11111111
binary.
Here is how binary octets convert to decimal: The right most bit, or least
significant bit, of an octet will hold a value of 20 . The bit just to the left of that
will hold a value of 21 . This continues until the left−most bit, or most
significant bit, which will hold a value of 27 . So if all binary bits are a one, the
decimal equivalent would be 255 as shown below.

1 1 1 1 1 1 1 1 128 64 32 16 8 4 2 1 (128+64+32+16+8+4+2+1=255)
Here is a sample octet conversion when not all of the bits are set to
1.
0 1 0 0 0 0 0 1 0 64 0 0 0 0 0 1 (0+64+0+0+0+0+0+1=65)
And this is sample shows an IP address represented in both binary
and decimal.
10. 1. 23. 19 (decimal) 00001010.00000001.00010111.00010011
(binary)
These octets are broken down to provide an addressing scheme
that can accommodate large and small networks. There are five
different classes of networks, A to E. This document focuses on
addressing classes A to C, since classes D and E are reserved and
discussion of them is beyond the scope of this document.

Note: Also note that the terms "Class A, Class B" and so on are used in
this document to help facilitate the understanding of IP addressing and
subnetting. These terms are rarely used in the industry anymore because
of the introduction of classless intra domain routing (CIDR).
Given an IP address, its class can be determined from the three
high−order bits. The following shows the significance in the three high
order bits and the range of addresses that fall into each class. For
informational purposes, Class D and Class E addresses are also shown.
IP Addressing and Subnetting

IP Subneting and Bassic network fundamental.pptx

In a Class A address, the first octet is the network portion, so the Class A example above has
a major network address of 10. Octets 2, 3, and 4 (the next 24 bits) are for the network
manager to divide into subnets and hosts as she sees fit. Class A addresses are used for
networks that have more than 65,536 hosts (actually, up to 16,581,375 hosts!). In a Class B
address, the first two octets are the network portion, so the Class B example above has a
major network address of 172.16. Octets 3 and 4 (16 bits) are for local subnets and hosts.
Class B addresses are used for networks that have between 256 and 65,536 hosts. In a Class
C address, the first three octets are the network portion. The Class C example above has a
major network address of 193.18.9. Octet 4 (8 bits) is for local subnets and hosts − perfect
for networks with less than 256 hosts.

Network Masks A network mask helps you know which portion
of the address identifies the network and which portion of the
address identifies the node. Class A, B, and C networks have
default masks, also known as natural masks, as shown below.
Class A: 255.0.0.0
Class B: 255.255.0.0
Class C: 255.255.255.0
An IP address on a Class A network that has not been subnetted
would have an address/mask pair similar to: 8.20.15.1
255.0.0.0. To see how the mask helps you identify the network
and node parts of the address, convert the address and mask to
binary numbers.
8.20.15.1 = 00001000.00010100.00001111.00000001
255.0.0.0 = 11111111.00000000.00000000.00000000

Once you have the address and the mask represented in binary, then
identifying the network and host ID is easier. Any address bits which have
corresponding mask bits set to 1 represent the network ID. Any address
bits that have corresponding mask bits set to 0 represent the node ID.
8.20.15.1 = 00001000.00010100.00001111.00000001
255.0.0.0 = 11111111.00000000.00000000.00000000
−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−
net id |
host id
netid = 00001000 = 8
hostid = 00010100.00001111.00000001 = 20.15.1

Understanding Subnetting
Subnetting allows you to create multiple logical networks that exist within a single Class A, B, or C network.
If you do not subnet, you will only be able to use one network from your Class A, B, or C network, which is
unrealistic.
Each data link on a network must have a unique network ID, with every node on that link being a member of
the same network. If you break a major network (Class A, B, or C) into smaller subnetworks, it allows you to
create a network of interconnecting subnetworks. Each data link on this network would then have a unique
network/subnetwork ID. Any device, or gateway, connecting n networks/subnetworks has n distinct IP
addresses, one for each network / subnetwork that it interconnects.
To subnet a network, extend the natural mask using some of the bits from the host ID portion of the
address to create a subnetwork ID. For example, given a Class C network of 204.15.5.0 which has a natural
mask of 255.255.255.0, you can create subnets in the following manner
204.15.5.0 − 11001100.00001111.00000101.00000000
255.255.255.224 − 11111111.11111111.11111111.11100000
By extending the mask to be 255.255.255.224, you have taken three bits (seen above as "sub") from the
original host portion of the address and used them to make subnets. With these three bits, it is possible to
create eight subnets. With the remaining five host ID bits, each subnet can have up to 32 host addresses, 30
of which can actually be assigned to a device since host ids of all zeros or all ones are not allowed (it is very
important to remember this). So, with this in mind, the following subnets have been created.

204.15.5.0 255.255.255.224 host address range 1 to 30
Note: There are two ways to denote the above masks. First, since you are using three bits more
than the "natural" Class C mask, you can denote these addresses as having a 3−bit subnet mask.
Or, secondly, the mask of 255.255.255.224 can also be denoted as /27 as there are 27 bits that
are set in the mask. This second method is used with CIDR. Using this method, one of the above
networks can be described with the notation prefix/length. For example, 204.15.5.32/27
denotes the network 204.15.5.32 255.255.255.224. When appropriate the prefix/length
notation is used to denote the mask throughout the rest of this document.

What is the OSI model?
The Open Systems Interconnection (OSI) Model is a description of how the Internet works. It
breaks down the functions involved in sending data over the Internet into seven layers. Each layer
has some function that prepares the data to be sent over wires, cables, and radio waves as a series
of bits.
The seven layers of the OSI model are:
•7. Application layer: Data generated by and usable by software applications. The main protocol
used at this layer is HTTP.
•6. Presentation layer: Data is translated into a form the application can accept. Some authorities
consider HTTPS encryption and decryption to take place at this layer.
•5. Session layer: Controls connections between computers (this can also be handled at layer 4 by
the TCP protocol).
•4. Transport layer: Provides the means for transmitting data between the two connected parties,
as well as controlling the quality of service. The main protocols used here are TCP and UDP.
•3. Network layer: Handles the routing and sending of data between different networks. The most
important protocols at this layer are IP and ICMP.
•2. Data link layer: Handles communications between devices on the same network. If layer 3 is
like the address on a piece of mail, then layer 2 is like indicating the office number or apartment
number at that address. Ethernet is the protocol most used here.
•1. Physical layer: Packets are converted into electrical, radio, or optical pulses and transmitted as
bits (the smallest possible units of information) over wires, radio waves, or cables.

IP Subneting and Bassic network fundamental.pptx

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