A 2-tier architecture involves clients communicating directly with servers that hold both the application and data tiers. A 3-tier architecture separates these functions into distinct tiers - clients interact with an application server tier that provides requested resources by accessing a separate data server tier. This separation of concerns allows for improved scalability, portability, and maintainability compared to a 2-tier architecture. Common web, application and database servers are discussed.

1. 2,3 & N TIER
ARCHITECTURE

2. Table of contents
 Introduction
 Client & server
 2tier architecture
 3tier architecture
 Applications of 2 & 3 tier architecture
 Conclusion

3. Introduction
 What is client??
 What is server??

4. What is client??
 Client (computing), software that accesses a remote
service on another computer known as a server, by
way of a network

5. What is server??
 A server is a computer, or series of computers, that
link other computers or electronic devices together
 For example, when you enter a query in a search
engine, the query is sent from your computer over the
internet to the servers that store all the relevant web
pages. The results are sent back by the server to your
computer.

6. Peer to peer architecture
 Peer-to-peer (P2P) computing or networking is a
distributed application architecture that partitions
tasks or work loads between peers.
 Peers are equally privileged, equipotent participants
in the application.

7. Coming back to client – server architecture
• A client makes a request to connect to a server for
providing some service.
• The services running on the server run on known
ports and the client needs to know the address of the
server machine and this port in order to connect to
the server.
• The first packet which the client sends as a request to
the server contains this information and this is then
further used by the server to send any information.

9. What is a Two-Tier Architecture?
 A two-tier architecture is where a client
communicate directly to a server. It is
typically used in small environments.

10.  In two-tier architecture, the server holds both
the application tier (Business Logic) and the
data tier (data).

11. Advantage & Disadvantage
Advantages Disadvantages
 Simple structure  Poor performance
 Dependability
 Easy to setup and maintain  Non-Scalable
 Not portable to other
 Good for small user groups database server.

13.  What is a 3-Tier Architecture
 In 3-tier architecture, there is an intermediary level, meaning
the architecture is generally split up between:
 A client, i.e. the computer which requests the resources,
equipped with a user interface (usually a web browser for
presentation purposes
 The Application server (also called middleware), whose task is
to provide the requested resources, but by calling on another
server
 The data server, which provides the application server with the
data it requires

16. Various Web Servers
 Apache - Web site hosted 378,267,399 (64.91%)
 IIS (MS) - 84,288,985 (14.46%)
 Nginx
 GWS
 Oracle (Sun)
 SSI, CGI, SCGI, FastCGI, PHP, Java Servlet, JavaServer
Pages, ASP, ASP .NET, Server API , JS, AJAX

17. Various Application Servers
 IBM Webshpere
 Jboss
 Oracle App. Server
 Tomcat
 WEbLogic
 Silver Stream

18. Various Database Servers
 Oracle
 DB2
 SQL Server
 Informix
 Ingress

19. N – Tier Architecture