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Client Server Computing

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Outline Meaning of Client Server Computing

Components & Functions of Client-Server Computing

Client-Server Security

Advantages of Client-Server System

Obstacles of Client-Server System

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Client CharacteristicAlways initiates requests to servers.

Waits for replies.

Receives replies.

Usually connects to a small numberof serversat one time.

Usually interacts directly with end-usersusing any user interfacesuch as graphicaluser interface.
http://simple.wikipedia.org/wiki/Serverhttp://simple.wikipedia.org/wiki/Serverhttp://simple.wikipedia.org/wiki/User_interfacehttp://simple.wikipedia.org/wiki/Graphical_user_interfacehttp://simple.wikipedia.org/wiki/Graphical_user_interfacehttp://simple.wikipedia.org/wiki/Graphical_user_interfacehttp://simple.wikipedia.org/wiki/Graphical_user_interfacehttp://simple.wikipedia.org/wiki/Graphical_user_interfacehttp://simple.wikipedia.org/wiki/Graphical_user_interfacehttp://simple.wikipedia.org/wiki/Graphical_user_interfacehttp://simple.wikipedia.org/wiki/User_interfacehttp://simple.wikipedia.org/wiki/User_interfacehttp://simple.wikipedia.org/wiki/User_interfacehttp://simple.wikipedia.org/wiki/Serverhttp://simple.wikipedia.org/wiki/Server

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ServerA server is also a person who serves, like

a waiterat a restaurant.

A server is a computerthat serves manythings to user, or clientmachines.
http://simple.wikipedia.org/wiki/Waiterhttp://simple.wikipedia.org/wiki/Computerhttp://simple.wiktionary.org/wiki/userhttp://simple.wikipedia.org/wiki/Clienthttp://simple.wikipedia.org/wiki/Clienthttp://simple.wiktionary.org/wiki/userhttp://simple.wikipedia.org/wiki/Computerhttp://simple.wikipedia.org/wiki/Waiter

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Server CharacteristicsAlways wait for a request from one of the

clients.

Serve clients requests then replies withrequested data to the clients.

A server may communicate with other

servers in order to serve a client request.

A server is a source which sends requestto client to get needed data of users.
http://simple.wikipedia.org/wiki/Clienthttp://simple.wikipedia.org/wiki/Serverhttp://simple.wikipedia.org/wiki/Serverhttp://simple.wikipedia.org/wiki/Client

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Meaning of Client-Server

Computing In Client-Server Computing, all large

modules need not all be executed within

the same memory space.

With this architecture, the calling modulebecomes the client (requesting service)

and the called module becomes the server(providing service).

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Meaning of Client-Server

Computing Clients and Servers are running separately

on appropriate hardware and software

platforms for their functions.

For example, database managementsystem servers running on platforms

specially designed and configured toperform queries, or file servers running onplatforms with special elements for

managing files.

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Component of Client Server

Computing Client-Server Computing is dividing into

three components, a Client Process

requesting service and a Server Processproviding the requested service, with aMiddleware in between them for their

interaction.

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ComputingA Client Server Process usually manages

the user-interface portion of the

application; validate data entered by theuser, dispatch requests to serverprograms.

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Computing the Server Process fulfills the client

request by performing the service

requested.After the server receives requests from

clients, it executes database retrieval,

updates and manages data integrity anddispatches responses to client requests.

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Computing Middleware allows applications to

transparently communicate with other

programs or processes regardless oflocation.

The key element of Middleware is NOS

(Network Operating System) that providesservices such as routing, distribution, andmessaging and network management

service.

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Function of Client Server

System File and hardware sharing

Managing disk quota

Setting file, directory and printer permissions Checking files and directories

How to share a file, directory and printer

Setting up network printers

Setting up network printer sharing devices

Installing print drivers and setting the printerproperties

How to install and remove network applications

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System Network management

How to manage basic tasks such as user account modification,eg setting up new users or deleting users from the system.

Ensuring understanding of which administrative tools

Check if the supplier has customized tools for schools to performuser and network management in some form of batchprocessing.

How to manage domains and trust relationships (grouping ofthe computers).

How to replicate directories.

Adding and removing computers from your network.

Using DHCP manager (to set up the network structure).

Viewing and assigning IP addresses for setting up internetaccess.

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System Security

Logging on and logging off

Change log-on password Locking and unlocking computer

How to manage security tools

Check security measures remain intact

Undertake periodic network and security analysis

Customizing and manage desktop environment

Accessing the Internet safely

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Function of Client ServerSystem

Remote access

Connecting to the school network from home

Accessing the Internet addressingauthentication and authorization

Managing and monitoring remote access

connections - accounting

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Function of Client ServerSystem

Disaster recovery (Service ContinuityManagement) How to start up and shut down servers Understand administrative alerts

View and manage event logs

Check server capacity and performance

Back up files to tape Run virus scanning tools and install updates

Apply updates to known software problems in earlier systemsand applications software

Restore files from back-up media

Prepare and apply emergency repair disk

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Client/Server security

Network environment has complexsecurity issues.

Networks susceptible to breaches ofsecurity through eavesdropping,unauthorized connections orunauthorized retrieval of packets ofinformation flowing round the network.Specific security issues include:

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Client/Server security

System-level password security usernames and passwords for allowing access tothe system. Password management utilities

Database-level password security - fordetermining access privileges to tables;read/update/insert/delete privileges

Secure client/server communication -via encryption but encryption cannegatively affect performance

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Advantages of Client ServerSystems:

client-server architecture enables theroles and responsibilities of

a computing system to be distributedamong several independent computersthat are known to each other only through

a network, so one of advantages of thismodel is greater ease of maintenance.
http://simple.wikipedia.org/wiki/Computinghttp://simple.wikipedia.org/wiki/Computer_networkhttp://simple.wikipedia.org/wiki/Computer_networkhttp://simple.wikipedia.org/wiki/Computing

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All the data is stored on the servers,which generally have better security

controls than most clients. Since data storage is centralized, updates

to that data are much easier to

administrators than what would bepossible under a P2P architecture.

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Many advanced client-server technologiesare already available

which were designed to ensure security,user friendly interfaces, and ease of use.

It works with multiple different clientsof

different specifications.
http://simple.wikipedia.org/wiki/Technologyhttp://simple.wikipedia.org/wiki/Designhttp://simple.wikipedia.org/wiki/Computer_securityhttp://simple.wikipedia.org/wiki/Clienthttp://simple.wikipedia.org/wiki/Clienthttp://simple.wikipedia.org/wiki/Computer_securityhttp://simple.wikipedia.org/wiki/Designhttp://simple.wikipedia.org/wiki/Technology

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Disadvantages of Client ServerSystem

Networks traffic blocking is one of theproblems related to the client-

servermodel.As the number of simultaneous client

requests to a given server increases, the

server can become overloaded

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Disadvantages of Client ServerSystem

Comparing client-server model tothe P2Pmodel, if one server fail, clients

requests cannot be served but in caseof P2P networks, servers are usuallydistributed among many nodes.
http://simple.wikipedia.org/wiki/Serverhttp://simple.wikipedia.org/wiki/Clienthttp://simple.wikipedia.org/wiki/Clienthttp://simple.wikipedia.org/wiki/Server

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