Addressing the Network
– IPv4
Network Fundamentals – Chapter 6
Version 4.0
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IPv4 Addressing
 Method for assigning addresses
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IPv4 Addressing
 Class A
•The class A address block was designed to support extremely
large networks with more than 16 million host addresses.
•Limited to 128 networks, they could only be allocated to
approximately 120 companies or organizations.
 Class B
•designed to support the needs of moderate- to large-size
networks with more than 65,000 hosts
 Class C
•provide addresses for small networks with a maximum of 254
hosts.
•Used a /24 prefix.
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Assigning Addresses
 The importance of using a structured process to assign
IP addresses to hosts.
•Preventing duplication of addresses
• Each host in an internetwork must have a unique address
•Providing and controlling access
• Some hosts, such as servers, provide resources to the
internal network as well as to the external network
•Monitoring security and performance
• identify the device on the network that has a problematic
address.
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Assigning Addresses
 End user devices can obtain addresses either statically
through an administrator or dynamically through DHCP
 Static
With a static assignment, the network administrator must
manually configure the network information for a host. At a
minimum, this includes entering the host IP address, subnet
mask, and default gateway.
 Dynamic
DHCP enables the automatic assignment of addressing
information such as IP address, subnet mask, default gateway,
and other configuration information.
The configuration of the DHCP server requires that a block of
addresses, called an address pool, be defined to be assigned to
the DHCP clients on a network.
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Assigning Addresses
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Assigning Addresses
 Internet Assigned Numbers Authority (IANA)
 IANA (http://www.iana.net) is the master holder of
the IP addresses. The IP multicast addresses and
the IPv6 addresses are obtained directly from
IANA
 IANA allocated IPv4 address space to various
other registries to manage for particular purposes
or for regional areas. These registration
companies are called Regional Internet Registries
(RIR).
 The following are the major registries:
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IPv6
 IPv6 creating expanded addressing capabilities was the initial
motivation for developing this new protocol. Other issues were also
considered during the development of IPv6, such as these:
• Improved packet handling
•Increased scalability and longevity
• Quality of service (QoS) mechanisms
• Integrated security
 To provide these features, IPv6 offers the following:
 128-bit hierarchical addressing to expand addressing capabilities

Header format simplification to improve packet handling

Improved support for extensions and options for increased scalability/longevity and improved
packet handling
 Flow-labeling capabilities as QoS mechanisms
 Authentication and privacy capabilities to integrate security
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Assigning Addresses
 IPv6
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Subnet mask
 Subnetting allows creating multiple logical networks
from a single address block.
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Subnet mask
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Subnet mask
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Subnet mask
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Testing the Network Layer
 Ping command can be used to determine if the IP
protocol is operational on a local host
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Testing the Network Layer
 Ping can be used to verify that a local host can
communicate with a gateway across a local area
network
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Testing the Network Layer
 Ping can be used to verify that a local host can
communicate via a gateway to a device in remote
network
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Testing the Network Layer
 Ping can be used to verify that a local host can
communicate via a gateway to a device in remote
network
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Testing the Network Layer
 Tracert/traceroute can be used to observe the path
between two devices as they communicate and trace
the steps of tracert/traceroute's operation
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Testing the Network Layer
 Tracert/traceroute can be used to observe the path
between two devices as they communicate and trace
the steps of tracert/traceroute's operation
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Summary
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