chapter 9 ip addressing

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IP Addressing

Chapter 9


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Chapter Objectives

Explain difference between dynamic andstatic addresses

Identify different classes of IP addresses

Describe IP Subnet

Identify IP Masks

Explain Classless IP addressing and CIDR

Explain special IP addresses Explain host addressing in Mobile IP


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Recall

NetBIOS include Name service, Session service andDatagram service

NetBIOS name cache contains NetBIOS names and

their corresponding IP addresses that were recently

resolved by local computer Supporting Protocols within IP layer are ARP,

RARP, ICMP and IGMP

Maximum Transfer Unit (MTU) specifies maximum

amount of data that a frame can carry within a

network


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IP Address

A Unique, 32-bit address used by computers tocommunicate over a computer network

Types of IP Address

Static Dynamic


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Classful IP Addressing - I

IP address structure consists of two addresses,Network and Host

IP address is divided into five classes

IP Address

Classes

Class A Class B Class C Class D Class E


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Classful IP Addressing - II

Network ID Host ID

Network ID Host ID

Network ID Host ID

Multicast Address

Class A

Reserved for future use

Class B

Class C

Class D

Class E

Byte 1 Byte 2 Byte 3 Byte 4


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Examples of Classful Addressing

14.23.120.8 - The first byte of the address

represents 14 which lies between 0 and

127, hence Class A address.

134.11.78.56 - The first byte of address is134 which lies between 128 and 191 hence

the address belongs to Class B.

193.14.56.22 - As first byte is 193 which isbetween 192 and 223, hence the address

belongs to Class C.


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Unicast, Multicast and Broadcast

Addresses

Used to achieve communication on the Internet

Unicast address uniquely identifies a host in a

network and belongs to class A, B and C

Multicast address defines an address for a group

and belongs to class D

Broadcast address allows user to send data packet

to all machines on a given network and is lastaddress of that network


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IP Subnetting

Allows you to divide a network into smaller sub-networks

Each subnet has its own sub-network address

Subnet can be created within Class A, B, or C basednetworks


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Subnet Mask

Specifies part of IP address used to identify asubnetwork.

Subnet mask when logically ANDed with IP address

provides 32-bit network address

AND

Operation

Subnet Mask

IP Address Network Address


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Default Mask

Has predetermined number of 1s

Class A, B and C contains 1s in network ID fields for

default subnet mask

Address

Class

Default Mask

(in Binary)

Class A 11111111.00000000.00000000.00000000

Class B 11111111.11111111.00000000.00000000

Class C 11111111.11111111.11111111.00000000


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Classless IP Addressing

Ruled out fixed size network address

Network address can vary from 0-bit to 31-bit

Uses Classless Inter-Domain Routing (CIDR)

addressing scheme CIDR address notation:

154.201.179.42/18

IP address

First 18 bits representnetwork ID


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Variable Length Subnet Mask (VLSM)

Used by CIDR to allocate IP addresses to subnets

depending up on the requirement

Allows network administrator to create variable size

subnets within a network Employs two different subnet masks at router which

are ANDed one after another to the address


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Example of VLSM - I

For example, if an organization is given a Class

C address and the organization needs to have

five subnets VLSM employs two subnet masks.

If the IP address is 201.70.64.0, consider thefirst subnet mask with 26 1s that is

255.255.255.192 or in binary format

1111111.11111111.11111111.11000000

which provides four subnets having 64

addresses in each subnet.


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Example of VLSM - II

Further, one of the subnet having 64 host

addresses is divided in two subnet having 32

hosts addresses by applying a mask of 27 1s

that is 255.255.255.224 or11111111.11111111.11111111.11100000

to one of the subnet from the four subnets. Refer

to the figure in next slide.


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Example of VLSM - III

201.70.64.0201.70.64.63

201.70.64.64201.70.64.127

201.70.64.128201.70.64.191

201.70.64.224201.70.64.254

201.70.64.192

201.70.64.223


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Case Study

The Moneymaker bank has been granted an IP address190.100.0.0/16 by IANA. The Bank has started its branches inDelhi, Bangalore, and Mumbai. It is seen that

The Delhi branch requires 64 networks while each network

needs 254 addresses The Bangalore branch must have 128 networks while each

network needs 126 addresses

The Mumbai branch requires 128 networks while eachnetwork needs 62 host addresses.

Design the subnetworks, give slash notation for eachsubnetwork and calculate the number of addresses which stillremain available after allocation of addresses.


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Problem

Implementing VLSM to create subnets within anetwork


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Special Addresses

IP addresses which are never used on the publicInternet

Types of Special

Address

Private AddressLoop-backAddress

Link-LocalAddress


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IPv6

Latest version of IP addressing over IPv4

Implements 128-bit network in contrast to 32-bit IP

address used by IPv4

Address notation consists of 32 hexadecimal digitswith every 4 digits separated by a colon


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Ping, Tracert and Path Ping

Utility tools used for keeping track about hosts onthe network and network structure

Ping (Packet Internet Groper) Used by computer

network to test whether intended host is reachable

across IP network TracertUsed by Windows operating system to

increase time-to-live (TTL) value of data packets

sent

Pathping

Provides useful information aboutnetwork errors, network latency and network loss at

hops between source and destination address


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Host Addressing In Mobile IP - I

Host cannot carry IP address from one network toanother

IP address is valid only when the host is connected

to a particular network

When a host moves from one network to another itrequires IP addressing structure to be modified

To maintain network connectivity of host within new

network:

Change IP address from one network to another

Use two IP addresses


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Host Addressing In Mobile IP - II

To maintain network connectivity of host within new

network:

Change IP address from one network to another -

Provides network connectivity for mobile host when it

travels from one network to another by changing IP

address of mobile host

Use two IP addresses - Host uses home address

when it is in permanent home network and uses care-

of-address when it moves to foreign network


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Agents in Mobile IP - I

Mobile IP includes

two agents to make

address changes

invisible to the rest of

the Internet

Agents

HomeAgent

ForeignAgent


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Agents in Mobile IP - II

Home agent Involves a routing device attached to home network of

mobile host

Transmitting data packet from host to mobile host

HostHome

Agent

Foreign

Agent

Mobile

Host

Packet

Foreign agent

Usually a router that is attached to foreign network

Receives packet sent by home agent and deliversthese packets to mobile host


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Phases in Mobile IP

While communicating with a remote host, a mobile

host has to undergo three phases


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Inefficiency in Mobile IP

Mobile IP sometime may provide with inefficient

communication which can be either severe or

moderate.

Inefficiency may be caused due to: Double Crossing

Triangle Routing


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SummaryII

CIDR makes use of VLSM to allocate IP addresses to

subnets depending upon the need of the organization

Routing devices on the Internet discard any IP datagram

or packet using private IP addresses

A Loop-back address is a test address which acts as a

test mechanism of network devices and protocols

IPv6 implements 128-bit network in contrast to 32-bit IP

address used by IPv4

Mobile IP allows mobile devices to move from one

network to another while maintaining the connectivity to

the Internet

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