This chapter discusses IP addressing and subnetting. It explains the TCP/IP protocol stack, which has four layers - application, transport, internet and network interface layers. It describes IP addressing, where every device has a unique 32-bit IP address represented as four octets. The chapter also covers subnet masks, which identify the network and host bits in an IP address, and how to calculate the number of subnets and hosts using subnetting.

1. IP Addressing
Chapter 2

2. Chapter Objectives
 Explain TCP/IP protocol stack
 Explain IP addressing
 Discuss IP subnetting
 Plan IP addressing
Chapter 2 2

3. Recall
 Physical and the Logical topology are the two types
of topologies
 LAN, MAN and WAN are the different types of
networks used
 Hierarchical model includes three layers, core layer,
distribution layer and the access layer
 Application layer, presentation layer, session layer,
transport layer, network layer, data link layer and the
physical layer are the different layers of the OSI
model
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4. TCP/IP Stack
 TCP/IP stack has four layers
TCP/IP
Network
Application
Interface
Transport Internet
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5. Application Layer
 Application layer clubs the functionality of application,
presentation, and session layers of the OSI model
 Protocols that function at the application layer include
 Hyper Text Transfer Protocol (HTTP)
 Simple Network Management Protocol (SNMP)
 File Transfer Protocol (FTP)
 Telnet
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6. Transport Layer
 Layer is responsible for source-to-destination
delivery of the entire message
 Ensures that the entire message arrives at the
destination computer
 Protocols that function in the transport layer include
 TCP
 User Datagram Protocol (UDP)
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7. Internet Layer
 Layer allows routing of data over the network
 Protocols that function in the network layer include
 Address Resolution protocol (ARP) - ARP
provides a method for finding the Media Access
Control (MAC) address of the host computer from
its IP address
 Reverse Address Resolution Protocol (RARP) -
RARP provides a method for finding the IP
address of the host computer from the MAC
address
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8. Internet Control Message Protocol
(ICMP)
 ICMP functions at the network layer of Internet
Protocol
 The protocol reports errors related to the delivery of
IP packets within a network
 ICMPs generate the following four messages
 Destination Unreachable message
 Echo request message
 Redirect message
 Time exceeded message
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9. IP Addressing
 IP address is a 32-bit binary number that is unique for each
device
 IP address is converted to a decimal format to make them
readable for the humans
 Within the network, the IP address is interpreted in a binary
format consisting of 0 and 1
 IP address of 10010100101000101001010010101011, it is
split into 4 octets such as
 10010100
 10100010
 10010100
 10101011
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10. IP Addressing
 To convert the bits to a decimal format, right most
bit in the octet has the least value of 20. This value
goes on increasing towards the left
Bits 1 0 0 1 0 1 0 0
Values 27 = 128 26 = 64 25 = 32 24 = 16 23 = 8 22 = 4 21 = 2 20 = 1
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11. IP Addressing
 You need to multiply the bits with its corresponding
value in the table
Bits 1 0 0 1 0 1 0 0
Values 27 = 128 26 = 64 25 = 32 24 = 16 23 = 8 22 = 4 21 = 2 20 = 1
Multiplied 128 0 0 16 0 4 0 0
Values
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12. IP Addressing
 The equivalent decimal value for the octet will be the
addition of all the multiplied values
 For the octet 10010100, the decimal value will be
128+0+0+16+0+4+0+0 = 148
 So the IP address of the machine will be
148.162.148.171
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13. Classification of IP Addresses
CLASSES
Class A Class B Class C Class D Class E
1-126 128 - 191 192 -223 224-239 240 - 255
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14. IP Address Components
 A network number denotes the network segment to
which the device is connected
 A host number specifies the address of the device in
the network segment. Host numbers are the
numbers between the network number and the
directed broadcast number
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15. Subnet Mask
 Subnet mask is used to identify the network bits and
host bits in the IP address
 A subnet mask always has a series of consecutive
1s followed by consecutive 0s
 A subnet mask cannot start with the bit 0 or ending
with the bit 1
Chapter 2 15

16. IP Subnetting
Chapter 2 16

17. Algorithm to determine the number of
hosts and subnets
 Identify the IP address structure
 Determine the number of network bits based on the
class of the IP address
 Determine the number of host bits based on the
number of 0s in the mask
 Determine the number of host bits using the formula,
32 – (network bits + host bits)
 Calculate the number of subnets using the formula,
2subnet bits – 2
 Calculate the number of hosts in each subnet using
the formula, 2host bits – 2
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18. Case Study
The Blue Diamond Steel organization located in
Gujarat is granted an IP address 220.56.64.0 by
Internet Assigned Numbers Authority (IANA). The
company requires five different subnets for its
Finance, Business Development, Software
Management, Project Management and Detailing
departments. The network administrator Robert needs
to design the subnets for the company.
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19. Problem
Finding IP address range for each subnet
Chapter 2 19

20. Suggested Solution
Find IP address range for each subnet
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21. Variable Length Subnet Mask (VLSM)
 VLSM allows you to use different masks for each
subnet
 Classful protocols such as Routing Information
Protocol version 1 (RIPv1) and IGRP do not support
VLSM
 Advantages of VLSM include
 Efficient use of IP addressing
 Route summarization
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22. Route Summarization
 Advantages of route summarization include:
 Reduction in the size of routing table, memory
requirement and time for processing
 Reduction in the size of updates and bandwidth
requirement
 Detection of networking problems that ensures
proper routing of the packets to the destination
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23. VLSM Design
 A VLSM design ensures efficient use of available IP
addresses as well as more-efficient routing update
communication using hierarchical IP addressing
 Design criteria that affect the functioning of the
VLSM technology include
 Total subnets required currently
 Total subnets that may be required in the future
 Number hosts on the largest subnet currently
 Number of hosts that may be required on the
largest subnet in future
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24. Planning IP Addressing
 Planning IP addressing include
 Identifying Network and Host Requirements
 Calculating Subnet Masks
 Identifying Network Addresses
 Identifying Directed Broadcast Addresses
 Identifying Host Addresses
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25. Summary - I
 TCP/IP is a protocol suite that allows data transfer
between network devices
 The Application layer clubs the functionality of
application, presentation, and session layers of the OSI
model
 The transport layer is responsible for source-to-
destination delivery of the entire message
 The network layer allows routing of data over the
network
 The data-link layer allows the source computer to add
meaningful bits to the data packet so that the destination
computer identifies it
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26. Summary - II
 Every device that is connected to the network using the
TCP/IP protocol requires an IP Address
 The IP address is a 32-bit number that is unique for each
device
 The IP address is converted to a decimal format to make
them readable for the human eye
 The 32-bit binary IP address is represented as 4 octets,
each consisting of 8 bits
 Every IP address consists of two parts, the network, and
the host number
 The network number identifies the network segment and
the host number identifies the actual device
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27. Summary - III
 Host numbers are the numbers between the
network number and the directed broadcast number
 Subnetting refers to the process of grouping a
definite number of devices
 A subnet mask allows us to identify the network
number and the host number of an IP address
 A subnet mask contains 32 bits similar to IP
addresses and is represented in a decimal form
separated by periods
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28. Summary - IV
 In a binary format, the bit 1 in the subnet mask
represents the network number and the bit 0
represents the host number
 A subnet mask always has a series of consecutive 1s
followed by consecutive 0s
 The higher order bits are always reserved for
subnetting
 The boolean AND operation enables us to identify the
subnet number in an IP address
 The directed broadcast address specifies all host
addresses on the particular network
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29. Summary - V
 You can calculate network and host requirements
using the following formulae:
 2X = > number of networks, where X refers to
number of subnet bits
 2Y – 2 = > hosts on largest segment, where Y
represents the host bits.
 X + Y <= total host bits
 Variable Length Subnet Mask (VLSM) allows you to
use different masks for each subnet to prevent the
wastage of address space
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