differcence between 2-tier and 3-tier

[Former Member]

hiii,

diff between 2-tier and 3-tier sap architecture??

[ferry_lianto]

Hi,

The 2 tier Architecure is for the Application Server and the Database Server.

The 3 tier Architecure is for the Presentation Server, Application Server and the Database Server.

Regards,

Ferry Lianto

[suresh_datti]

NO....

2 tier is Client <---> Server (Database)

3 tier for Client <--> Application Server <-->Database Server

~Suresh

[Former Member]

Hi..,

3 tier means it includes the Presentation server also...

2 tier means it will have onli the Application Layer and Database Layer..

IN 3 tier architecture Each layer can as <b>Server</b> for the layers above it..

and acts as <b>Client</b> for the layers below them...

<b>Thats y it is a 3 tier client server architecture..</b>

regards,

sai ramesh

[Former Member]

chaitanya,

In 2 tier the presentation server and application server will be combined to form a system and v will have a separate database server.

In case of 3 tier all the three servers r in three different systems.

Regards...

Arun.

Reward points if useful.

[Former Member]

2-tier is where you have the application logic and

presentation logic run on one server and the database logic

run on another.

3-tier is where you have the application logic run on one

server, the presentation logic on another, and the database

operations on yet another server

[Former Member]

chaitanya,

In 2 tier the presentation server and application server will be combined to form a system and v will have a separate database server.

In case of 3 tier all the three servers r in three different systems.

Regards...

Arun.

Reward points if useful.

[Former Member]

chaitanya,

In 2 tier the presentation server and application server will be combined to form a system and v will have a separate database server.

In case of 3 tier all the three servers r in three different systems.

Regards...

Arun.

Reward points if useful.

[Former Member]

hi guys,

i had a problem with my internet connectivity that's y my reply was sent many times.

sorry for that.

Regards...

Arun.

[Former Member]

Hi chaitanya,

Main difference between two-tier and three-tier architecture apart from the hardware and software perspectives are in their performance:

-> A three-tier architecture provides Scalability, the ability to distribute the workload among different application servers and even increase the capacity of the existing system.

-> Also the thing to note is that The access is via TCP/IP and

consumes very little network bandwidth. Essential for WAN links, SAP has the lowest network bandwidth demand of all ERP solutions.

The following e-book has Nice explanation,

<a href="http://www.hp.com/hpbooks/prentice/chapters/0130280844.pdf">SAP system architecture</a>

with regards,

Naveenan.

[former_member1109645]

The easiest way to explain this is, as you suggest, by an example. So I'll give you an example.

Let's suppose I'm going to write a piece of software that students at a school can use to find out what their current grade is in all their classes. I structure the program so that a database of grades resides on the server, and the application resides on the client (the computer the student is physically interacting with).

When the student wants to know his grades, he manipulates my program (by clicking buttons, menu options, etc). The program fires off a query to the database, and the database responds with all the student's grades. Now my application uses all this data to calculate the student's grade, and displays it for him.

This is an example of a 2-tier architecture. The two tiers are:

1. Data server: the database serves up data based on SQL queries submitted by the application.

2. Client application: the application on the client computer consumes the data and presents it in a readable format to the student.

Now, this architecture is fine, if you've got a school with 50 students. But suppose the school has 10,000 students. Now we've got a problem. Why?

Because every time a student queries the client application, the data server has to serve up large queries for the client application to manipulate. This is an enormous drain on network resources.

So what do we do? We create a 3-tier architecture by inserting another program at the server level. We call this the server application. Now the client application no longer directly queries the database; it queries the server application, which in turn queries the data server.

What is the advantage to this? Well, now when the student wants to know his final grade, the following happens:

1. The student asks the client application.

2. The client application asks the server application.

3. The server application queries the data server.

4. The data server serves up a recordset with all the student's grades.

5. The server application does all the calculations to determine the grade.

6. The server application serves up the final grade to the client application.

7. The client application displays the final grade for the student.

It's a much longer process on paper, but in reality it's much faster. Why? Notice step 6. Instead of serving up an entire recordset of grades, which has to be passed over a network, the server application is serving up a single number, which is a tiny amount of network traffic in comparison.

There are other advantages to the 3-tier architecture, but that at least gives you a general idea of how it works.

Incidentally, this website is a 3-tier application. The client application is your web browser. The server application is the ASP code which queries the database (the third tier) for the question-and-answer you requested.

I hope that helps! dont forget to give points if useful