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Introduction to Internet Layer

Protocols/IP ..

Shudhanshu AgarwalB.tech (EC-2011)Roll no.-1101421102

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CONTENTS:1. Introduction2. Internetworking

Models3. Internet layer

protocols4. IP Addressing5.Private IP

addresses6.Conclusion

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Two main reasons for using Internet Layer :

1. For routing2. Providing a single

network interface to upper layer s

INTRODUCTION

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Protocols of Internet layer

1. Internet Protocol2. Internet Control Message

Protocol3. Address Resolution Protocol4. Reverse Address Resolution

Protocol5. Proxy ARP

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In 1970s OSI Reference Model was formed.

Helped the different vendor networks to communicate.

Describes data and information transfer from one to another computer.

The OSI has seven layers ,divided into two groups :

Internetworking Models

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1. The upper layers :

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2. The lower layers :

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Looks at each packets address.Helps in identifying the devices.Receives segments from host-to-host layer and fragments them into datagrams .

The IP Header gives the idea of what the IP protocol has to go through.

INTERNET PROTOCOL

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THE IP HEADER :

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It is a management protocol and message service provider for IP.

Its packets :1. Can provide host with

information about network problems.

2. Are encapsulated within IP datagrams.

ICMP

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EXAMPLE :

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Finds the hardware address of a host

ARP

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Requests for an IP address for a particular MAC address :

RARP

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Help machines on a subnet reach remote subnets without configuring routing or even a default gateway.

It can be added to a single router without disturbing the routing tables of the other routers.

PROXY ARP

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It is a software address.It was designed to allow hosts on one network to communicate with the host on different network.

It consists of 32 bits of information and these bits are divided into four equal octets separated by a dot.

IP Addressing

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Bit Byte Octet Network Address Broadcast Address

IP Terminology

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Network address : It uniquely identifies each network.

Node address : It uniquely identifies each machine on a network.

The designers of Internet created classes of network based on the network size.

Network Addressing

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The various classes of networks are :

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Here the first bit of the first byte must be off, or 0.

Address must be between 0 and 127.

Consider the following network address:

0 x x x x x x x

Network Address Range: Class A

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If we turn the other 7 bits all off and then turn them all on ,we’ll find the range of class A network address:

00000000 = 001111111 = 127

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Here the first bit of the first byte must always be turned on but the second bit must always be turned off.

Address must be between 128 and 191.

Consider the following network address:

Network Address Range: Class B

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1 0 x x x x x x

If we turn the other six bits all off and then turn them all on ,we’ll find the range of class B network address:

10000000 = 12810111111 = 191

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Here the first two bits of the first octet are always turned on but the third bit can never be on.

Address must be between 192 and 223.

Consider the following network address:

Network Address Range: Class C

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1 1 0 x x x x x

If we turn on other five bits all off and then turn them all on, we’ll find the range of class C network address.

11000000 = 19211011111 = 223

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The addresses between 224 and 255 are reserved for class D and E networks.

Class D(224-239) is used for multicast addresses .

Class E (240-225) is use for scientific purposes.

Network Address Ranges: Classes D and E

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Some Reserved IP Addresses ...

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First byte : network address.

Remaining bytes : node address.

Format is:

network.node.node.node

Class A Addresses:

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First two bytes : network address.

Remaining two bytes : node address.

Format is

network.network.node.node

Class B Addresses:

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first 3 bytes : network address.

Last byte : node address.Format is:

network.network.network.node

Class C Address:

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It is used on private network.

It saves IP.

It uses Network Address Translation to accomplish the task.

Private IP Address:

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Reserved IP addresses:

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Overview of OSI reference modelAbout IP ,ICMP, ARP, RARP, Proxy ARP

use of Class A ,B and C AddressingImportance of Private IP Address.

CONCLUSION:

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