CASE STUDY

COMPUTER NETWORKS

Submitted to:

Prof. Vandana Kadam

Submitted by : A040 SONAL . SHETH. A041 SONAM . SINGH. A042 BHUSHAN. TAMBE. A043 DEVAYANI. TELANGE.

THE K.E.T’s V.G.VAZE COLLEGE OF ARTS , SCIENCE AND COMMERCE.

MITHAGAR ROAD

MULUND ( E ) – 400 081.

CONTENTS :

1]. Introduction

2]. Connecting devices

3]. Communication channel

4]. Data Transmission

5]. Topology

6]. Line configuration

7]. Transmission mode

8]. Server

9]. Switching method

10]. Category of the network

11]. Security

12]. Network Layout

INTRODUCTION :

Given is the synopsis for the case study of a networking system in one of the KOTAK MAHINDRA’s branchin dombivali.

Place : Kotak Mahindra Bank , Dombivali (w)

Date Of Visit : 20 august , 2009 . Kotak Mahindra Bank is one of the best organization where we can study about networking and clear our concepts. We selected this particular network, so that the impact of networking on a corporate world can be studied closely. Mr .Prasad Mehta, a network engineer, actually helped us to clear our all queries and concepts of networking. In this case study, we have mainly focused on the concepts of technological development in networking field, along with the network design. We were really interested to :

1]. To know how network operates?

2]. What types of technology is available?

3]. How does information flow?

4]. Who is sharing the data and what kind of data is being shared ? etc… So finally, We have studied and tried to put forward the concepts of networks, in a simplest form. We have described the theory of every component in Kotak Mahindra Bank, to make the concepts clear and easy.

BASIC CONCEPTS :

Kotak Mahindra Bank has in all 34 centers in Mumbai. Its main branch (head office) is in Wadala.

The center has 20 computers, named from A to T and have multiple laser printers which are shared by all the computers. These are called as nodes, i.e. linking devices. It also has a TMS (Token Machine System).

CONNECTING DEVICES :

Connecting devices used are switches and routers. Switches are used because a hub has only 8 ports and if a system wants to connect more than 8 devices to a hub, a hub becomes inefficient .So a switch is used to connect a number of devices, which is then connected to one of the port of a hub, so that the rest of the ports of the hub remain free.

THEORY :

Switches : They are hardware and/or software devices capable of creating temporary connections between two or more devices linked to a switch , but not to each other.

Routers : It is an interconnecting device. Routers are more complicated. They have access to network layer addresses and contain software that enables them to determine which of several possible paths between those addresses is the best for a particular transmission. Thus, routers relay packets among multiple interconnected networks. Routers operate in physical data link and network layers of the OSI model.

COMMUNICATION CHANNEL :

The devices are connected to a switch using cat-5 UTP (unshielded twisted pair) straight Cu-cable. The end connectors used for the cat-5 cables are called RJ-45 (regulated Jacks 45) connector.

THEORY :

The medium defines the speed at which data can travel through a connection.

Cat-5 Unshielded twisted pair cable : It is a cable belonging to category 5. It supports upto 10 megabit/sec. These cat-5 cables are capable of carrying data effectively at about 80-90 m . Main advantages of UTP are its cost and ease of use . UTP is cheap , flexible and easy to install.

RJ-45 : It is a snap-in plug like connector with 8 conductors. The connector is attached to the cable and the jack is the device that the connector plugs into. Thus, one end of cat-5 cable is inserted in RJ-45 slot of computer and other end is terminated on Ethernet port of a switch.

DATA TRANSMISSION :

The transmission of binary data across a link is accomplished in serial mode.

THEORY :

Serial Data Transmission : In serial data transmission one bit follows another , so we need only one communication channel rather than ‘n’ to transmit data between two communicating devices.

The advantage of serial data transmission is that with only one communication channel, serial transmission reduces the cost of transmission over parallel by roughly a factor of ‘n’.

In serial mode, one bit is sent with each clock pulse.

TOPOLOGY :

In this centre, a star topology is used. Because, it is less expensive, requires less cabeling and easy to install and reconfigure.

THEORY : The term topology refers to the way a network is

laid out, either physically or logically.

Two or more devices connect to a link; two or more links form a topology.

Topology of an network is the geometric representation of the relationship of all the links and linking devices to each other.

There are four basic topologies possible. 1]. Mesh 2]. Star 3]. Bus 4]. Ring

These four topologies describe how the devices in a network are interconnected rather than their physical arrangement.

STAR TOPOLOGY : In a star topology, each device has a dedicated point to point link only to a central controller , usually called a ‘hub’.

The devices are not directly linked to each other.

A star topology does not allow direct traffic between devices.

The controller acts as an exchange. If one device wants to send data to another, it sends the data to the controller, which then relays the data to the other connected device.

A star topology is less expensive. In a star topology, each device needs only one link and one I/O port to connect it to any number of other devices. This factor makes it easy to install and reconfigure.

Other advantage is robustness. If one link fails, only that link is affected. All other links remain active. So, as long as, a hub is working , it can be used to monitor link problems and detect defective links. So, it leads to easy fault identification and fault isolation.

DEVICE A

DEVICE B

HUB

DEVICE C

DEVICE D

LINE CONFIGURATION :

For communication, point to point line configurations is used.

THEORY :

Line configuration : It refers to the way two or more communication devices attach to a link. A link is the physical communication pathway that transfers data from one device to another.

Point To Point Configuration : It provides a dedicated link between two devices. The entire capacity of the channel is reserved for transmission between those two devices.

Most point to point line configuration use an actual length of wire or cable to connect the two ends, but other options, such as microwave or satellite links are also possible.

TRANSMISSION MODE :

The transmission mode used is full-duplex.

THEORY :

Transmission mode : The term is used to define the direction of signal flow between two linked devices.

Full-duplex mode : In duplex mode, both stations can transmit and receive simultaneously.

In full duplex mode, signals going in either direction share the capacity of the link. This sharing can occur in two ways : either the link must contain two physically separate transmission paths, one for sending and another for receiving , or the capacity of the channel is divided between signals traveling in opposite directions.

SERVER :

The main server is in Wadala. It stores the database of all connecting devices. When we make and changes in a file stored in a particular device, connected to a server , same changes are made to the file which is stored on the server. The application installed in every connecting device, can be accessed directly from the server as well.

THEORY :

Server is a computer or a device with high storage capacity, that stores all data, entered on the various devices, connected to the server.

A server is really important data storage system and also it is very sensitive. Thus, it is kept in a separate room called ‘server room’.

SWITCHING METHOD :

It uses packet switching method.

THEORY :

In a packet – switched network, data are transmitted in discrete units of potentially variable length blocks called ‘packets’.

The maximum length of the packet is established by the network. Longer transmissions are broken up into multiple packets. Each packet contains not only data but also a header with control information.

The packets are sent over the network node to node. At each node, the packet is stored briefly then routed according to the information.

CATEGORY OF THE NETWORK :

Local area network (LAN) used , allows to share different resources like laser printer between computers.

THEORY :

A local area network is usually privately owned and links the devices in a single office, building or campus. LAN size is limited to a few kilometers.

LAN are designed to allow resources to be shared between personal computers or workstations. The resources to be shared can include a hardware or a software.

LAN’s are distinguished from other types of networks by their transmission media, size and

topology. A given LAN may use only one type of transmission medium.

Traditionally, LAN’s have data in the 4 to 16 Mbps range.

IP ADDRESS :

All the branches of Kotak Mahindra use ‘0’ ( zero ) series IP address , specified by Kotak Mahindra’s head branch. It comes under class A.

SECURITY :

Network security issues include protecting data from unauthorized access and viruses.

Unauthorized access : For a network to be useful , sensitive data must be protected from unauthorized access. Protection can be accomplished at a number of levels. At the lowest level are user identification codes and passwords. Every device has its own network address, by which anyone can connect to the device and access the data. But if a user identification code and password are not known then we can connect to that device but cannot access the data.

At a higher level, are encryption techniques. In these mechanisms, data are systematically altered in such a way that if they are intercepted by an unauthorized user, it will not be accessible.

VIRUSES : Because a network is accessible from many points it can be prone to computer viruses. A virus is an illicitly introduced code that damages the system. A good network is protected from viruses by hardware and software designed specially for that purpose.

NETWORK LAYOUT :

Every centre of Kotak Mahindra sends its data to the main branch for updating.

All computers, from A to T, are attached to a switch with the help pf a cat-5 cable and RJ-45 connector. One end of the cat-5 cable is inserted in RJ-45 slot of computer and other end is terminated on Ethernet port of a switch.

The switch is then connected to a hub. One port of hub has a connection with a laser printer, which is shared by all the computers, Also, a hub has a connection with a TMs ( Token Machine System ), so that TMS can register the token of a customer on

the computer, directly. Other ports of a hub remain free.

HUB is then connected to a router, which route the packets from one network to the other, so that it gets to the final destination.

Since, the data cannot be sent directly through a network, it has to convert into digital form, in short, it has to be modulated, so that it can travel through a network easily and safely. For this, a modem is connected to a router, which modulates and transfers the data through lease lines.

To setup the internet connection, various service providers such as Siffy broadband, Reliance , etc are used.

When a connection is established, data flows through the lease lines and is received by the modem at the receiver’s side i.e. at the main centre. Modem then demodulates the data and sends it to the router connected to it.

Routers then route this data to the main server and data gets stored on the server.

If the device at the receiver’s side wants to reply to the data to one of the device, the entire process is reversed.

In this way data can be received and accessed by any Kotak Mahindra branch.

CONCLUSION : This is how networking takes place in Kotak Mahindra’s branch.