BY,

BHARAT SHETTY

POOJA SHETTY

ANKITA SHETTY

NIKITA RAI

SAVIN SHETTY

COMPUTER NETWORKS

INTRODUCTION

NETWORK TOPOLOGY (ANKITA SHETTY)

TYPES OF NETWORKS (BHARAT SHETTY)

TYPES OF SERVER (NIKITA RAI)

COMPONENTS OF NETWORKS (POOJA SHETTY)

OSI MODEL (SAVIN SHETTY)

BIBLIOGRAPHY

INDEX

WHAT IS NETWORKING?

Networking is the word basically relating to computers and their connectivity.

The term networking implies the link between two or more computers and their devices, with the soul purpose of sharing the data stored in the computers, with each other.

Networking can be either wired or wireless.

INTRODUCTION

Computer network topology is the way various components of a network are arranged.

The way in which different systems and nodes are connected and communicate with each other is determined by topology of the network.

Topology can be physical or logical.

Physical Topology is the physical layout of nodes, workstations and cables in the network; while Logical Topology is the way information flows between different components.

NETWORK TOPOLOGY

BUS TOPOLOGY

In Bus Topology, all the nodes (computers as well as servers) are connected to the single cable .

This central cable is the backbone of the network and is known as Bus.

Every workstation communicates with the other device through this Bus.

TYPES OF TOPOLOGIES

ADVANTAGES  It is easy to set-up and extend bus network.

Bus topology costs very less.

 Cable length required for this topology is the least compared to other networks.

There is a limit on central cable length and number of nodes that can be connected.

If the main cable (i.e. bus ) encounters some problem, whole network breaks down.

It is difficult to detect and troubleshoot fault at individual station.

 Maintenance costs can go higher with time.

Efficiency of Bus network reduces as the number of devices connected to it increases.

It is not suitable for networks with heavy traffic.

DISADVANTAGE

In Star topology, all the components

of network are connected to the

central device called nodes were

connected to central cable,

here all the workstations are

connected to central device with a

point-to-point connection.

So it can be said that every computer is indirectly connected to every other node by the help of “HUB”.

All the data on the star topology passes through the central device before reaching the intended destination.

STAR TOPOLOGY

As compared to Bus topology it gives far much better performance.

In star topology new nodes can be added easily without affecting rest of the network.

Failure of one node or link doesn’t affect the rest of network. At the same time its easy to detect the failure and troubleshoot it.

DISADVANTAGE Too much dependency on central device has its own drawbacks. If

it fails whole network goes down.

The use of hub, a router or a switch as central device increases the overall cost of the network.

ADVANTAGES

In Ring Topology, all the nodes are

connected to each-other in such a

way that they make a closed loop.

Each workstation is connected to

two other components on either side,

and it communicates with these two

adjacent neighbors.

Data travels around the network, in one direction.

Sending and receiving of data takes place by the help of TOKEN.

RING TOPOLOGY

In ring topology all the traffic flows in only one direction at very high speed.

Even when the load on the network increases, its performance is better than that of Bus topology.

There is no need for network server to control the connectivity between workstations.

DISADVANTAGE

Each packet of data must pass through all the computers between source and destination. This makes it slower than Star topology.

If one workstation or port goes down, the entire network gets affected.

Network is highly dependent on the wire which connects different components.

ADVANTAGES

In a mesh network topology, each

network node, computer and other

devices are interconnected with one

another.

Every node not only sends its own

signals but also relays data from

other nodes.

In fact a true mesh topology is the one where every node is connected to every other node in the network.

MESH TOPOLOGY

Data can be transmitted from different devices simultaneously.

This topology can withstand high traffic.

Even if one of the components fails there is always an alternative present, So that data transfer doesn’t get affected.

DISADVANTAGE

There are high chances of redundancy in many of the network connections.

Overall cost of this network is way too high as compared to other network topologies.

Set-up and maintenance of this topology is very difficult. Even administration of the network is tough.

ADVANTAGES

LAN (LOCAL AREA NETWORK) A local-area network (LAN) is a computer network that

spans a relatively small area.

Most LANs are confined to a single building or group of buildings.

Each node (individual computer) in a LAN has its own CPU with which, it executes programs, but it also is able to access data and devices anywhere on the LAN.

Speed of LAN varies from 1 mbps-30 mbps (megabits per second).

TYPES OF NETWORKS

A Metropolitan area network (MAN) is a computer network that usually spans a city or a large campus.

A MAN usually interconnects a number of local area networks (LANs) using a high-capacity backbone technology, such as fiber-optical links, and provides up-link services to wide area networks (or WAN).

The network size falls intermediate between LANs and WANs.

A MAN typically covers an area of between 5 and 50 km diameter.

Speed of MAN ranges at 10 mbps.

MAN (METROPOLITAN AREA NETWORK)

A Wide Area Network (WAN) is a network that covers a broad area (i.e., any network that links across metropolitan, regional, or national boundaries).

The term Wide Area Network (WAN) usually refers to a network which covers a large geographical area.

Wide-Area Networks are commonly connected either through the Internet or special arrangements made with phone companies or other service providers.

In a WAN, one network may be anywhere from several hundred miles away, to across the globe in a different country.

WAN (WIDE AREA NETWORK)

In LAN, workstations are connected to each other by means of a hub or a repeater. These devices propagate any incoming data throughout the network. However, if two people attempt to send information at the same time, a collision will occur and all the transmitted data will be lost. Once the collision has occurred, it will continue to be propagated throughout the network by hubs and repeaters.

Hence, a bridge or a switch can be used. These devices will not forward collisions, but will allow broadcasts The workstations, hubs, and repeaters together form a LAN segment.

Defining broadcast and collision domains in a LAN depends on how the workstations, hubs, switches, and routers are physically connected together. This means that everyone on a LAN must be located in the same area .

VLAN ( VIRTUAL LOCAL AREA NETWORK )

What are Servers?

Server is a computer or a device that manages network resources such as file, printer, and user group as well as network traffic on the network.

During the server selection two parameter are very important to consider that is server specification and processor specification.

There are also some more specification to be consider are memory, storage, connectivity, operating system support specifications.

SERVERS

TYPES OF SERVER

APPLICATION SERVER

An application server is a server that provides software applications with services such as security, data services, transaction support, load balancing, and management of large distributed systems.

The term is often used for web servers that support the Java Platform, Enterprise Edition; however its use isn't restricted to Java.

A catalog server provides a single point of access that allows users to centrally search for information across a distributed network.

In other words, it indexes databases, files and information across large network and allows keywords, Boolean and other searches.

Catalog Server

Communications servers are open, standards-based computing systems that operate as a carrier-grade common platform for a wide range of communications applications and allow equipment providers to add value at many levels of the system architecture.

LAN is basically used with Communication server

COMMUNICATION SERVER

A database server is a computer program that provides database services to other computer programs or computers, as defined by the client–server model. The term may also refer to a computer dedicated to running such a program. Database management systems frequently provide database server functionality.

Such a server is accessed either through a "front end" running on the user’s computer which displays requested data or the "back end" which runs on the server and handles tasks such as data analysis and storage.

Database servers

In computing, a file server is a computer attached to a network that has the primary purpose of providing a location for shared disk access, i.e. shared storage of computer files (such as documents, sound files, photographs, movies, images, databases, etc.) that can be accessed by the workstations that are attached to the same computer network.

It is designed primarily to enable the storage and retrieval of data while the computation is carried out by the workstations.

File servers are commonly found in schools and offices, where users use a LAN to connect their client computers.

FILE SERVER

A game server (sometimes host or shard) is a server which is the authoritative source of events in a multiplayer video game.

The server transmits enough data about its internal state to allow its connected clients to maintain their own accurate version of the game world for display to players.

They also receive and process each player's input.

Game Server

A proxy server is a server (a computer system or an application) that acts as an intermediary for requests from clients seeking resources from other servers.

A client connects to the proxy server, requesting some service, such as a file, connection, web page, or other resource available from a different server and the proxy server evaluates the request as a way to simplify and control their complexity.

Today, most proxies are web proxies, facilitating access to content on the World Wide Web.

PROXY SERVER

A print server, or printer server, is a device that connects printers to client computers over a network.

It accepts print jobs from the computers and sends the jobs to the appropriate printers.

A print server may be a networked computer with one or more shared printers.

Alternatively a print server may be a dedicated device on the network, with connections to the LAN and one or more printers.

Print server functionality may be integrated with other devices such as a wireless router, a firewall, or both.

Print server

A WIRELESS PRINT SERVER

LAN CARDS With the increasing use of the computers and the

networking the local area network of the LAN is one such network type which links the two computers in a connection.

For this connection a Local area network card or the LAN card is required which enables the connection of the computers in a network.

It is a piece of hardware which is connected inside the PC linking the computer network.

The LAN cards usually are designed to support the rate transfer to be ranging from 10 to 1000 megabits per second.

COMPONENTS OF NETWORK

A common connection point for devices in a network. Hubs are commonly used to connect segments of a LAN. A hub contains multiple ports. When a packet arrives at one port, it is copied to the other ports so that all segments of the LAN can see all packets.

TYPES OF HUBS

A PASSIVE HUB serves simply as a conduit for the data, enabling it to go from one device (or segment) to another.

ACTIVE HUBS.

INTELLIGENT HUBS include additional features that enables an administrator to monitor the traffic passing through the hub and to configure each port in the hub. Intelligent hubs are also called manageable hubs.

HUB

A network switch or switching hub is a computer networking device that connects network segments or network devices.

Network switches appear nearly identical to network hubs, but a switch generally contains more intelligence (and a slightly higher price tag) than a hub.

Unlike hubs, network switches are capable of inspecting data packets as they are received, determining the source and destination device of each packet, and forwarding them appropriately.

By delivering messages only to the connected device intended, a network switch conserves network bandwidth and offers generally better performance than a hub.

SWITCH

Router is a device that forwards data packets between computer networks, creating an overlay internet work.

A router is connected to two or more data lines from different networks.

The most familiar type of routers are home and small office routers that simply pass data, such as web pages and email, between the home computers and the owner's cable or modem, which connects to the Internet through an ISP

ROUTER

A bridge device filters data traffic at a network boundary. Bridges reduce the amount of traffic on a LAN by dividing it into two segments.

A bridge reads the outermost section of data on the data packet, to tell where the message is going.  

It reduces the traffic on other network segments, since it does not send all packets.

 Bridges forward all broadcast messages.

BRIDGES

A modem (modulator-demodulator) is a device that modulates an analog carrier signal to encode digital information, and also demodulates such a carrier signal to decode the transmitted information.

The goal is to produce a signal that can be transmitted easily and decoded to reproduce the original digital data.

The most familiar example is a voice band modem that turns the digital data of a personal computer into modulated electrical signals in the voice frequency range of a telephone channel.

These signals can be transmitted over telephone lines and demodulated by another modem at the receiver side to recover the digital data.

MODEM

The Open Systems Interconnection (OSI) model is a product of the OPEN SYSTEM INTERCONNECTION effort at the International Organization for Standardization (ISO).

It is a prescription of characterizing and standardizing the functions of a communications system in terms of abstraction layers.

A layer serves the layer above it and is served by the layer below it.

There are in all 7 layers in OSI model :

OSI (OPEN SYSTEM INTERCONNECTION ) MODEL

APPLICATION LAYER (Layer 7)

The Application Layer  is the OSI layer closest to the end user, which means that both the OSI application layer and the user interact directly with the software application.

This layer also interacts with software applications that implement a communicating component.

•

partner

PRESENTATION LAYER (Layer 6)

The presentation layer transforms data into the form that the application accepts.

This layer formats and encrypts data to be sent across a network. It is sometimes called the Syntax layer.

•

SESSION LAYER (Layer 5)

The Session layer controls the dialogues (connections) between computers.

Session Layer establishes, manages and terminates the connections between the local and remote application.

It set’s up by connection establishment, data transfer and connection release.

Responsible for establishing and maintaining communications channels. In practice, often combined with the Transport Layer.

Facilitates a dialogue between communicating systems and controls the dialogue: (transmission modes)

• Simplex

• Half-duplex

• Full duplex

TRANSPORT LAYER (Layer 4)

The Transport Layer provides transparent transfer of data between end users, providing reliable data transfer services to the upper layers.

The transport layer ensures the control flow control, segmentation/desegmentation, and error control.

NETWORK LAYER (Layer 3)

The Network Layer provides the functional and procedural means of transferring variable length data sequences from a source host on one network to a destination host on a different network.

Establishes a connection between two nodes by physical and logical addressing.

Layer’s primary function is to deliver packets from the source network to the destination network.

DATA LINK LAYER (Layer 2)

It is responsible for Segmentation of upper layer datagrams (also called packets) into frames in sizes that can be handled by the communications

hardware. It receives request

from the network layer and gives request to physical layer.

PHYSICAL LAYER (Layer 1)

Transmits the raw bit stream and includes electrical signalling and includes electromagnetic features like hubs, repeaters, etc.

It defines the relationship between a device and a transmission medium.

 

WWW.GOOGLE.COM

WWW.WIKIPEDIA.COM

http://computer.howstuffworks.com

BIBLIOGRAPHY