2 tier client server architecture v/s 3 tier client server architecture

Shamayel Afzal Khan (F-46066) – BBA 23 (B) – Semester 4, Spring 2012 - APCOMSClass Assignment- Fundamentals of Database-4th June 2012

2-Tier Client Server Architecture vs. 3-Tier Client Server Architecture

2-Tier Client Server Architecture vs. 3-Tier Client Server

Architecture

1. 2-Tier Client Server Architecture :

i. Definition :

It is a client server architecture based on 2-Tier, which implies that the Clients

and Server are on two different machines: such that the application layer is on

the client’s side and the database lies on the Server side. There are two layers

i.e. the client layers and the server or the database layer.

ii. Explanation:

In 2-Tier Client Server Architecture, client sends a request to the server through

the client machine, as a result a response is sent back to the client machine after

the server performs the required task.

However, there is a difference between the traditional and modern 2-Tier Client

Server Architecture. Previously, the client machine has the application layer

which use to slow down the client’s machine. Now, in the modern 2-Tier Client

Server Architecture, the server holds the application layers along with the

database layer for the reason that the server is a powerful processing machine

with large disk space. Therefore, it reduces the burden over the client’s

machine.

iii. Advantages :

a. It is easy to be established as compared to the 3-Tier Client Server

Architecture.

b. The Client has more access to the database and can easily use some special

tools as compared to the 3-Tier Client Server Architecture.

iv. Disadvantages :

a. It cannot process requests from clients beyond a certain limit at a time.

b. The processing speed is very slow.

c. It takes more time to process the requests.

d. It has a drawback of cost inefficiency as most of the users can only use the

connection 2-3 % of their time.

e. It lacks the portability feature.

v. Figure :

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2. 3-Tier Client Server Architecture :

i. Definition :

It is a client server architecture based on 3-Tier, which implies that the Clients

and Server are on two different machines with an addition of a third

intermediate layer known is application layer or web layer: such that the

application layer or the web layer is in between the client and the server. There

are three layers i.e. the client layers and the server or the database layer and the

web layer or the application layer.

ii. Explanation:

In 3-Tier Client Server Architecture, the application layer neither is on the

server machine, nor is it on the client’s machine but instead, it is on a separate

machine. However, the server as a whole consists of both the application layer

and the database layer. In this regards, the client is at the front just request the

data and it is displayed to him on his machine.

With the introduction of an additional tier, the system is easy to manage as the

load of requests, processing is equally shared among the machines. Thus, as a

result, the server is either processing the data or using the application. No

additional resources are being consumed. The cycle goes on in a way that the

client request is sent to application server from where it is sent to the database

server, which processes the request and sends the data back to the application

server and finally the application server sends the data to the client.

iii. Advantages :

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a. The modification as well as the replacement of any single tier can takes

place without affecting any other tier.

b. There is an efficient sharing of load through its distribution in form of three

layers.

c. The data integrity checks can be placed without affecting the clients. Only

the accurate data can be allowed to update.

d. The data access is more secure through introduction of security checks and

in this regards the client cannot directly access the database server.

e. The failure rate is comparatively low than the 2-Tier Client Server

Architecture.

f. The processing rate is quicker than the 2-Tier Client Server Architecture.

g. The performance is better, as the Business Logic is separate from the

database and is on a separate application layer. It has a benefit that from the

scalability aspect i.e. the application server can be based on more than one

machine.

h. It has a portability feature.

iv. Disadvantages :

a. It is more complex.

b. Some of its advantages are overlooked, when the user needs a direct access

to database in order to use special tools such as report generation.

v. Figure :

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2 tier client server architecture v/s 3 tier client server architecture

Documents

apcoms class

shamayel afzal

tier client

application

web layer

special tools

portability

application