Client Server Building Blocks

7/27/2019 Client Server Building Blocks

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Client /Server Building Blocks


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Client ,Server ,Middleware

Architecture is applied to construction of

building . These building blocks can be rearranged to use

them in the following situations:

In C/S architecture ,we have to decide

How an application is split in Client ,Server What function goes on client & on Sever

Can Client /Server Play at home

Can Client /server Accommodate business of all

sizes .


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Client/Server for Tiny Shops and

Nomadic Tribes


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It is easy to run the client and server portionof an application on the same machine.

Vendors can easily package single-userversions of a client/server application.

The business critical client/server application

runs on one machine and does someoccasional communications with outsideservers to exchange data, refresh a databaseand send or receive mail and faxes. Ex:Internet.


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Only OS has to be chosen properly .

An office with one server cancommunicate with outside server .(e.g

.internet ).


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Client /Server for small shops &

Departments

The client/server architecture is particularly well-

suited for the LAN-based single server

establishments.

It consists of multiple clients talking to a local server.

This is the model used in small businesses.

The single-server nature of the model tends to keep

the middleware simple.

The client only needs to look into a configuration file

to find its servers name.

Security is implemented at the machine level and

kept quite simple.


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The network is usually relatively easy to

administer; its a part-time job for amember of the group.

There are no complex interactions

between servers, so it is easy to identify

failures- theyre either on the client or onthe local server.

E.gs corporate ,branch office of banks

Fax & Mail can be sent thro Mail server


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Middleware


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Client /Server for Intergalactic

enterprises

Mix and heterogeneous servers .

Internet ,Intranet

Client /Server are upwardly scalable .

When more processing power is needed for various

intergalactic functions, more servers can be added,

or the existing server machine can be traded up for

the latest generation of superserver machine

For multiservers ,low-cost, high speed bandwidth .

The servers can be partitioned based on the function

they provide, the resource they control, or the

database they own


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Middleware creates a common view of all the

services on the network called a singlesystem image.

Good middleware with features like network

directory ,RPC ,network time services .


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Client /Server for post scarcity world .

Every machine is both a client and a full-function server.

Because every machine is a full-function server, it willrun, at a minimum, a file server, database server,workflow agent, TP Monitor, and Web server - allconnected via an ORB.

This is in addition to all the client software and

middleware.


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In next few years, a hundred million

machines or more may be running almostall the forms of client/server software

In this model instead of mobile agents,

personal agents will be used.


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Building Blocks


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The Client building block

The Client Building Block

Runs the client side of the application It runs on the OS that provides a GUI or an OOUI

and that can access distributed services,

wherever they may be.

The client also runs a component of the

Distributed System Management (DSM) element.

Runs client side of the application .


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The server Building block The Server Building Block

Runs the server side of the application

The server application typically runs on top of someshrink-wrapped server software package.

The five contending server platforms for creating thenext generation of client/server applications are SQLdatabase severs, TP Monitors, groupware servers,Object servers and the Web server.

The server side depends on the OS to interface withthe middleware building block.

The server also runs DSM component

It may be a simple agent or a shared object database

etc


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The Middleware Building Block

Runs on both the client and server sides of anapplication

This broken into three category

Transport Stacks

NOS

Service-specific middleware


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Middleware is the nervous system of the

client/server infrastructure This also has the DSM component


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DSM (Distributed System Management)

Runs on every node in the client/server

network. A managing workstation collects information

from all its agents on the network and

displays it graphically.

The managing workstation can also instructits agents to perform actions on its behalf.


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Server-to-server Middleware

Server-to-server interactions are usuallyclient/server in nature - servers are clients to

other servers. However, some server-to-server interactions

require specialized server middleware. Forexample, Two-Phase commit protocol may be

used to coordinate a transaction that executeson multiple servers.

Servers on mail backbone will use specialserver-to-server middleware for doing store-

and-forward type messaging.


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But most modern software follows theclient/server paradigm

Middleware doesnt include the s/w that

provides actual service .

It has s/w that is used to coordinate

interserver interactions .


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The web as Middleware

The web initially consisted of a messaging andtransport protocol (http), an addressing scheme,a multimedia standard for document elements(MIME), and a human-readable markuplanguage called HTML .All of these componentsworked under the TCP/IP transport stack. The

connectionless transport protocol, and theability to create hypertext links betweendocuments, produced a relatively lightweight,flexible, environment for very low cost electronic

publishing.


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Server-to server Middleware .

Middleware doesnt include the s/w that

provides actual service . It has s/w that is used to coordinate

interserver interactions .

Servertoserver interactions are usually

Client/server in nature .

Client Server Building Blocks

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