what is client server technology?

Question

what is client server technology?

Answer 1

you have seen misguiding epics.



The following brief discussion can help u.



A client is a software process which can send request for a service, say a file( as in file transfer protocol client) or some kind of data(as in case of Internet Explorer which is a browser i.e. an web client or http client) etc.



The client must also be able to receive the response to the sent request i.e. it must be able to receieve the service.



A server is a software process which can receive requests for a service and provide the requested service. Examples are ftp servers(file servers), http servers(Web servers like Apache or IIS), Database servers (like Oracle), print servers etc.



The client process and the server process usually run on different

machines, but they may also run on the same machine(which is frequently the case during development of small client server applications).



Never think that a server has to be the big rackmount machine in the back room where no one is allowed to enter. It may also be, that the very machine u r using, is serving as a file server to a few other machines in the network. Probably that is to allow your subordinates to access files created by u. Any machine which runs a server process is acting as a server.



Did that help u sweetheart ?

Answer 2

Explaining in a Simple Way.



Client - Something that requires a Service

Server - Something that offers a Service



Client sends/asks for Service, which can be anything like process/ module/ Data from database.

Server processes the request and accepts it, if it can do the job, and if the requestung client is eligible (or authorised) to request that job. Then the server sends back the Response( Data / Acknowledgement/ Resource/Process Control) if needed.



In case of Networks, it will be like this :

A network architecture in which each computer or process on the network is either a client or a server. Servers are powerful computers or processes dedicated to managing disk drives (file servers), printers (print servers), or network traffic (network servers ). Clients are PCs or workstations on which users run applications. Clients rely on servers for resources, such as files, devices, and even processing power.



Another type of network architecture is known as a peer-to-peer architecture because each node has equivalent responsibilities. Both client/server and peer-to-peer architectures are widely used, and each has unique advantages and disadvantages.



Client-server architectures are sometimes called two-tier architectures.





For more advanced explanation, try peeking into

http://en.wikipedia.org/wiki/Client-server

http://searchnetworking.techtarget.com/sDefinition/0,,sid7_gci211796,00.html

Answer 3

In Client Server technolgy, server should be installed. This server will serve the clients request. Some group of clients will form as a domain. In Peer-to-Peer, there will be no server, whenever if a client request another client on the network, the host system will be treated as the server to process that request.

Answer 4

In simpler terms, the client is your machine and the application that you see running. When you process a request like running a report or a SQL transaction, it is sent from the client to server to be process from the server and sent back to the client.



Think of it a an ATM transaction. You are the client requesting money from your bank (server).

Answer 5

lots of the internet is largely shopper-server (with the internet internet site being a shopper, and the 'decrease back end' it is processing your requests and offering internet pages as a server). the internet browser does not do a good number of processing, yet with javascript, flash, java, etc it is appearing some. fantastically lots each organization makes use of "shopper-server" technologies for some component of their company. The classic occasion is a database it extremely is shared over the entire application, with varied shopper machines having access to it.

Answer 6

Client/server is a network computing architecture that has gained very widespread popularity. Get acquainted with the terminology and the key issues associated with client/server.





Client/server is a computational architecture that involves client processes requesting service from server processes.



In general, client/server maintains a distinction between processes and network devices. Usually a client computer and a server computer are two separate devices, each customized for their designed purpose. For example, a Web server will often contain large amounts of memory and disk space, whereas Web clients often include features to support the graphic user interface of the browser such as high-end video cards and large-screen displays.



Client/server networking, however, focuses primarily on the applications rather than the hardware. The same device may function as both client and server; for example, Web server hardware functions as both client and server when local browser sessions are run there. Likewise, a device that is a server at one moment can reverse roles and become a client to a different server (either for the same application or for a different application).

Client/Server Applications



Some of the most popular applications on the Internet follow the client/server design:



* Email clients

* FTP (File transfer) clients

* Web browsers



Each of these programs presents a user interface (either graphic- or text-based) in a client process, that allows the user to connect to servers. In the case of email and FTP, the user enters a computer name (or sometimes an IP address) into the interface to set up future connections to the server process.



For example, an Earthlink subscriber enters the name smtp.earthlink.net into the configuration settings of their email client to allow them to send messages over the Internet. In the case of email, a person generally enters the server information only one time, as the server side of the connection rarely changes. In the case of FTP, however, one typically enters a different server name each time they use the program. One day a person may visit ftp.earthlink.net to download tools, the next day they may visit ftp.microsoft.com to find a software patch, and so on.



When using a Web browser, the name or address of the server appears in the URL of each request. Although a person may start a Web surfing session by entering a particular server name (such as www.about.com), the name regularly changes as they click links on the pages. In the Web model, server information is provided by the HTML content developer encoded in the anchor tags.

Client/Server at Home



Many home networkers use client/server systems without even realizing it. Microsoft's Internet Connection Sharing (ICS), for example, relies on DHCP server and client functionality built into the operating system. Cable modem and DSL routers like those from Linksys also include a DHCP server with the hardware unit. Many home LAN gaming applications also use a single-server/multiple-client configuration.

Pros and Cons of Client/Server



Client/server was originally developed to allow more users to share access to database applications. Compared to the mainframe approach, client/server offers improved scalability because connections can be made as needed rather than being hard-wired. The client/server model also supports modular applications. In the so-called "two-tier" and "three-tier" types of client/server systems, a software application is separated into modular pieces, and each piece is installed on hardware specialized for that subsystem.



One area of special concern in client/server networking is system management. With applications distributed across the network, it can be challenging to keep configuration information up-to-date and consistent among all of the devices. Likewise, upgrades to a newer version of a client/server application can be difficult to synchronize or stage appropriately. Finally, client/server systems rely heavily on the network's reliability; redundancy or fail-over features can be expensive to implement.

Conclusion



Network clients request information or a service from a server, and that server responds to the client by acting on that request and returning results. This approach to networking has proven to be a cost-effective way to share data between tens or hundreds of clients. Usually the client and server are two separate devices on a LAN, but client/server systems work equally well on long-distance WANs (including the Internet).



Client/server is just one approach to distributed computing. The client/server model has been popular for a long time, but recently peer-to-peer networking has re-emerged as a viable alternative. Other approaches like clustering also have benefits in specific situations.

Answer 7

Client/Server technology is a means for separating the functions of an application into two or more distinct parts. The client presents and manipulates data on the desktop computer. The server acts like a mainframe to store and retrieve protected data. Together each machine can perform the duties it is best at.



The client/server software architecture is a versatile, message-based and modular infrastructure that is intended to improve usability, flexibility, interoperability, and scalability as compared to centralized, mainframe, time sharing computing.



A client is defined as a requester of services and a server is defined as the provider of services. A single machine can be both a client and a server depending on the software configuration.



This technology description provides a summary of some common client/server architectures and, for completeness, also summarizes mainframe and file sharing architectures. Detailed descriptions for many of the individual architectures are provided elsewhere in the document.



Mainframe architecture (not a client/server architecture). With mainframe software architectures all intelligence is within the central host computer. Users interact with the host through a terminal that captures keystrokes and sends that information to the host. Mainframe software architectures are not tied to a hardware platform. User interaction can be done using PCs and UNIX workstations. A limitation of mainframe software architectures is that they do not easily support graphical user interfaces or access to multiple databases from geographically dispersed sites. In the last few years, mainframes have found a new use as a server in distributed client/server architectures.



File sharing architecture (not a client/server architecture). The original PC networks were based on file sharing architectures, where the server downloads files from the shared location to the desktop environment. The requested user job is then run (including logic and data) in the desktop environment. File sharing architectures work if shared usage is low, update contention is low, and the volume of data to be transferred is low. In the 1990s, PC LAN (local area network) computing changed because the capacity of the file sharing was strained as the number of online user grew (it can only satisfy about 12 users simultaneously) and graphical user interfaces (GUIs) became popular (making mainframe and terminal displays appear out of date). PCs are now being used in client/server architectures.



Client/server architecture. As a result of the limitations of file sharing architectures, the client/server architecture emerged. This approach introduced a database server to replace the file server. Using a relational database management system (DBMS), user queries could be answered directly. The client/server architecture reduced network traffic by providing a query response rather than total file transfer. It improves multi-user updating through a GUI front end to a shared database. In client/server architectures, Remote Procedure Calls (RPCs) or standard query language (SQL) statements are typically used to communicate between the client and server.



The remainder of this write-up provides examples of client/server architectures.



Two tier architectures. With two tier client/server architectures, the user system interface is usually located in the user's desktop environment and the database management services are usually in a server that is a more powerful machine that services many clients. Processing management is split between the user system interface environment and the database management server environment. The database management server provides stored procedures and triggers. There are a number of software vendors that provide tools to simplify development of applications for the two tier client/server architecture.



The two tier client/server architecture is a good solution for distributed computing when work groups are defined as a dozen to 100 people interacting on a LAN simultaneously. It does have a number of limitations. When the number of users exceeds 100, performance begins to deteriorate. This limitation is a result of the server maintaining a connection via "keep-alive" messages with each client, even when no work is being done. A second limitation of the two tier architecture is that implementation of processing management services using vendor proprietary database procedures restricts flexibility and choice of DBMS for applications. Finally, current implementations of the two tier architecture provide limited flexibility in moving (repartitioning) program functionality from one server to another without manually regenerating procedural code.



Three tier architectures. The three tier architecture emerged to overcome the limitations of the two tier architecture. In the three tier architecture, a middle tier was added between the user system interface client environment and the database management server environment. There are a variety of ways of implementing this middle tier, such as transaction processing monitors, message servers, or application servers. The middle tier can perform queuing, application execution, and database staging. For example, if the middle tier provides queuing, the client can deliver its request to the middle layer and disengage because the middle tier will access the data and return the answer to the client. In addition the middle layer adds scheduling and prioritization for work in progress. The three tier client/server architecture has been shown to improve performance for groups with a large number of users (in the thousands) and improves flexibility when compared to the two tier approach. Flexibility in partitioning can be a simple as "dragging and dropping" application code modules onto different computers in some three tier architectures. A limitation with three tier architectures is that the development environment is reportedly more difficult to use than the visually-oriented development of two tier applications. Recently, mainframes have found a new use as servers in three tier architectures



Three tier architecture with transaction processing monitor technology. The most basic type of three tier architecture has a middle layer consisting of Transaction Processing (TP) monitor technology (see Transaction Processing Monitor Technology). The TP monitor technology is a type of message queuing, transaction scheduling, and prioritization service where the client connects to the TP monitor (middle tier) instead of the database server. The transaction is accepted by the monitor, which queues it and then takes responsibility for managing it to completion, thus freeing up the client. When the capability is provided by third party middleware vendors it is referred to as "TP Heavy" because it can service thousands of users. When it is embedded in the DBMS (and could be considered a two tier architecture), it is referred to as "TP Lite" because experience has shown performance degradation when over 100 clients are connected. TP monitor technology also provides the ability to update multiple different DBMSs in a single transaction connectivity to a variety of data sources including flat files, non-relational DBMS, and the mainframe the ability to attach priorities to transactions robust security



Using a three tier client/server architecture with TP monitor technology results in an environment that is considerably more scalable than a two tier architecture with direct client to server connection.



Benefits

The following are what are considered to be the benefits of client/server computing.



Many times easier to implement client/server than change a legacy application.



New technology and the move to rapid application development such as object oriented technology



Long term cost benefits for development and support. Easy to add new hardware to support new systems such as document imaging and video teleconferencing which would not be feasible or cost efficient in a mainframe environment. Can implement multiple vendor software tools for each application.



Concerns

The following are concerns for companies willing to implement client/server computing.





There are many layers of complexity and compatibility issues between the client and server.

Cost will rise in the short term since you will need to maintain the old system (mainframe) and the new client server architecture development.

Capabilities of the software such as security and management tools are not as mature as mainframe counterparts.

Takes time to become proficient with these tools.

Information System departments may balk at giving up control of a centralized computing environment.



Limitations



There a number of tradeoffs that must be made to select the appropriate client/server architecture. These include business strategic planning, and potential growth on the number of users, cost, and the homogeneity of the current and future computational environment.