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Subnetting: Partss of a Network are called subnetwork or subnet consisting of host machines. And spliting a web into smaller and manageable pieces called subnetting. Subnet Numbers: All of the IP references are 32-bit long and have a subnet field known as subnet Numberss. The spots that are designated with the web spots give the needed sum of subnet plants.

So harmonizing to this IP reference 192.228.17.56 with the web reference of 192.288.17.32 the subnet mask is 255.255.255.224. As it demoing down:

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192.228.17.32 =11000000.11100000.00010001.00100000

The default of category C mask =11111111.11111111.11111111.00000000

255.255.255.224 =11111111.11111111.11111111.11100000

The subnet spots are 3 ( because of the first three 1s ) and the host spots are 5 ( figure of 0s ) .

Subnet figure = 2x ( where ten is figure of subnet spots in the mask ) .

So the subnet figure for the IP reference will be = 23 = 8.

Network references: is a alone figure to place a machine in the web. Computers can find the reference of other computing machines on the web by utilizing the web reference in order to direct and have messages among them.

For this IP reference 192.228.17.56 we need 32 hosts from which we can utilize.

So the first subnet is 0. And all of the 8 subnets are:

0 So the first web reference is: 192.228.17.0 in binary 11000000.11100100.00010001.00000000

0 + 32 = 32 ( add32 ) So the 2nd web reference is 192.228.17.32 in binary 11000000.11100100.00010001.00100000

32 + 32= 64 ( still add 32 ) So the 3rd web reference is 192.228.17.64 in binary 11000000.11100100.00010001.01000000

64 + 32 = 96 ( still add 32 ) So the 4th web reference is 192.228.17.96 in binary 11000000.11100100.00010001.01100000

96 + 32 = 128 ( still add 32 ) So the 5th web reference is 192.228.17.128 in binary 11000000.11100100.00010001.10000000

128 + 32 = 160 ( still add 32 ) So the 6th web reference is 192.228.17.160 in binary 11000000.11100100.00010001.10100000

160 + 32 = 192 ( still add 32 ) So the 7th web reference is 192.228.17.192 in binary 11000000.11100100.00010001.11000000 192 + 32 = 224 ( still add 32 ) So the last web reference is 192.228.17.224 in binary 11000000.11100100.00010001.11100000

Broadcast subnet reference: is particular IP reference that is used to direct message to all the machines in a subnet. The Broad dramatis personae reference can non be assigned to any host.

And the broadcast reference is ever the figure which come before the following subnet

Network reference

& A ; binary signifier of broadcasts

192.228.17.0

192.228.17.32

192.228.17.64

192.228.17.96

192.228.17.128

192.228.17.160

192.228.17.192

192.228.17.224

## 11000000.11100100.00010001.11111111

NetMasks: it ‘s a mask which has 32bits and used to divide an IP reference in two parts subnets and stipulate the webs available hosts, Furthermore it ‘s used to reassign message right among machines in the same subnet.

As the IP reference given 192.228.17.56 is a category C, the default mask is 255.255.255.0, in binary it is = 11111111.11111111.11111111.00000000

So harmonizing our IP reference the netmask is 255.255.255.224, and it is in binary = 11111111.11111111.11111111.11100000

Host Numbers: it ‘s a alone figure of peculiar host when all hosts sharing the same web prefix. But if any two hosts which are in different webs the same figure can be used for both of them.

To happen the host Numberss for the IP reference 192.228.17.56 and the web reference 192.228.17.32 firs we have to happen the subnet mask. And as we have worked out above the subnet mask is 255.255.255.224 which is in double star:

## 11111111.11111111.11111111.11100000

So we use merely the 0s ( the spots turned off ) for host addressing. So it means we have 5 spots.

Host figure = 25 – 2 = 30

It means we have 30 Numberss of hosts in each subnet.

Network reference

Valid host scope

192.228.17.0

192.228.17.1 -to- 192.228.17.30

192.228.17.32

192.228.17.33 -to- 192.228.17.62

192.228.17.64

192.228.17.65 -to- 192.228.17.94

192.228.17.96

192.228.17.97 -to- 192.228.17.126

192.228.17.128

192.228.17.129 -to- 192.228.17.158

192.228.17.160

192.228.17.161 -to- 192.228.17.190

192.228.17.192

192.228.17.193 -to- 192.228.17.222

192.228.17.224

192.228.17.225 -to- 192.228.17.254

## Question1 Part ( B )

Class C is the 3rd category of the IP references which is set under category A and B, besides it sets upper than category D and category E which is the last category.

## Class C: 192.0.0.0 to 223.255.255.255

In order to cipher the figure of host a simple expression can be used: 2^bits, Class C IP reference has 21 spots for web and 8 spots dedicated for host.Using the expression:

2^ 21 =2,097,152 possible webs.

2^ 8 =256-2=254 possible host where we subtract 2 where 1 IP is for the web Id, and the other 1 is for the broadcast.

Analyzing subnetted IP from inquiry 1 ( a ) 192.228.17.32 we have 8 bombers webs

23 = 8 bomber webs AND

25 – 2 = 30 possible hosts

But if we use 1 host for Router per subnet than we can see that we are losing 3 IP ‘s per subnet that is 24 IPs for 8 subnets. The chief benefit for subnetting a web that it is more manageable and effectual.

## Question1 Part ( degree Celsius )

Open Systems Interconnection ( OSI ) theoretical accounts trades with linking unfastened systems.It has seven beds or degrees. And each bed which sets on the following lower bed to execute more crude maps. Furthermore layer must supply services to the following higher bed. Besides change in order of one bed does n’t necessitate to alter the remainder of them.

Application bed

Presentation bed

Session bed

Transport bed

Network bed

Physical bed

## The architecture of the Open System interconnectedness Models is shown in above tabular array and it has been briefly explained that which layer trades with precisely what.

1. The Physical Layer

This is the last bed and it ‘s more concerned with conveying natural spots over a communication/physical channel. And it fundamentally works on mechanical, electrical, functional, procedural, timing interfaces and physical transmittal mediums that lies below the physical bed.

Undertaking of this bed is to supply for the dependable transportation of information across physical nexus. It sends frames which has of import synchronism, mistake control and flux control. This bed is farther divided into two beds:

a- Medium Access Control ( MAC Layer )

b- Logic Link Control ( LLC Layer )

3. The Network Layer

The web bed fundamentally provides the routing installations for the information packages. It deals with exchanging or doing logical waies and admiting the information packages. It provides upper beds with independency from the informations transmittal and besides exchanging engineerings used to linking the system which is responsible for puting up, keeping and ending connexions.

4. The Transport Layer

The basic undertaking of this bed is to supply dependable crystalline transportation of informations between last portion of the point, moreover it offers ( terminal to stop mistake recovery and flow controls ) . Besides it determines what kinds of service to supply to session bed.

5. The Session Layer

The session bed manages the session. It creates the session and when the communicating between two nodes is done it merely destroys the session. It provides the control construction for the communicating between application like ; establishes, manages and terminates connexions ( Sessionss ) between collaborating applications.

6. The presentation bed

This bed presents informations in a meaningful format ( i.e. compress, encode, and change over informations ) . This besides called sentence structure bed because it is concerned with the sentence structure of the information presentations to transmitted. It helps the application processes by supplying independency from differences in term of informations representation sentence structure.

7. The Application Layer

It contains a assortment of user applications ( e-mail, ftp, file transportation, ECT ) . Which are normally needed by the user. One widely used protocol is HTTP which is the footing for World Wide Web. It besides provides distributed information services.

Benefits of OSI Reference Model

The thought of concealed objects fits really absolutely with the modern thoughts about object oriented scheduling.

Each bed provides some services without cognizing the other beds how these services were implemented.

None of the theoretical accounts is perfect. The OSI Model was ne’er easy to implement. It appeared that OSI Model would take over all the undertakings and take a clasp on the universe but it did non go on. These were the grounds considered chiefly.

## Question1 Part ( vitamin D )

Degree 1, 2 and 3 devices are Hubs, repeaters, Bridgess, switches, and routers. These devices are used for different intents like to linking hosts to a web doing them move like a individual section like hubs do, choosing the traffic way like routers do, and linking multiple webs like Bridgess do.

## Router

A router is a specialised web device which determines the following point at web to which informations package to direct toward its finish. They Works on OSI bed 3 which is ( web bed ) .

## Hub

Hubs works on OSI bed 1which is ( The Physical Layer ) . HubsA are used to connects multiple Ethernet sections together physically doing them move as a individual unit or section. Every node behaves as a individual broadcast sphere and hit sphere when we use a hub device and it allows merely one computing machine to convey at one clip because it ‘s utilizing the same sphere. Depending on the web Technology, the hubs connexion among the web objects are at basic degree 1. By utilizing a hub we get dedicated connexions between single nodes. And it provides shared bandwidth among all the objects.

## Question 2 Part ( a )

Head: it ‘s a device which read and writes informations from one platter in the disc, and in each side of platter there are normally two caputs.

Cylinder: It ‘s a three dimensional construct which has the set of all paths that are at one arm place makes up a cylinder. There may be 1000s of homocentric cylinders in a disc thrust.

Path: it ‘s homocentric rings on a disc.Also it ‘s a portion of cylinder. Each path is divided into wedge-shape countries called sector. Furthermore it ‘s making by low degree format of a disc.

Sector: it ‘s a little portion of the path which holds 512 bytes. Besides it can keep the operating expense bytes which is used to supply mistake corrections and clocking recovery under the low degree format in the lifecycle of the disc thrust.

Blocks: are fundamentally sectors or group of sectors ; modern discs have arrays of coupled list logical blocks where the logical block is the smallest unit of transportation. Always the size of a logical block is smaller than the physical block size.

## Question 2 Part ( B )

Dos Boot Record: it ‘s a portion which contains the turning boot codification written in assembly linguistic communication and mistake messages for the disc volume. Each divider has its ain boot sector excessively and each operating system has its ain boot sector format. What ‘s more the DOS is the stander of Disc Operating System.

Fat: there are several types of fat file system and each one has different purpose than the remainders so for illustration Fat12 ( floppy ) .And Fat12,16,32bits which is a bunch reference size.

Fat 1: it ‘s a first allotment tabular array, where bunch stored it ‘s information in. And it ‘s of import for blocks which can cover with allocated and unallocated blocks. Furthermore it sets following to volume boot sector in the disc.

Fat 2: it ‘s a 2nd transcript of fat.And it sets after fat1 directory.

Root Directory: is the chief directory where all other directories, sub directories, booklets or files are placed. It is the top-level directory in the file-system hierarchy it contains file names and metadata.

Loose infinite: It ‘s the infinite left in any of the bunch that is non being used. Or it is Any free infinite which still among a last byte of the file and a first byte where a following bunch is a form of internal atomization is known as a file slack or slack infinite.

## Question 2 Part ( degree Celsius )

Differences

Contiguous allotment

## Performance

Needs immediate memory and memory wasted. Files can non turn.

It solves the superficial -fragmentation and size-declaration jobs of the immediate allotment. So it ‘s better than immediate allotment in term of public presentation.

## Disk infinite direction

External Fragmentation, tonss of holes outside files. Wasteful of infinite ( dynamic storage-allocation job ) .

Free direction system and no wasteful of infinite.

## File size direction

Each file occupies a set of immediate blocks on the disc.

Each file is a coupled list of disc blocks: blocks might be dispersed anyplace on the disc.

## Random entree of blocks

Random entree.

Simple – merely necessitate the starting location which is at ( barricade # ) and length ( the figure of blocks which are required ) .

No random entree.

Allocate as needed, link together. Example, file starts at block 9

## ( 1 ) .Hard disc size in bytes.

Hard disc size ( bytes )

= Number of cylinders A- figure of caputs A- sectors/track A- 512 =

=512A-16A-63A-512=264241152 bytes

## ( 2 ) The minimal physical file size in bytes.

One bunch equal 2 sectors

and each sector has 512 bytes

So in 2 sectors there are

= 2 A-512 =1024bytes which is the minimal physical size in bytes.

## ( 3 ) The slack infinite size in byte for a file size 912 bytes?

Slack space=The physical file size in bytes -The file size in bytes ( 912 ) =

1024 – 912 bytes = 112 bytes