Advantages and disadvantages of Multitier architecture?

Answer 1

Advantages and Disadvantages of 3-Tier Architecture in Web DevelopmentA 3-Tier Architecture (3TA) is traditionally used when building web applications. It makes a logical separation between the presentation layer, the business logic layer, and the database layer.

The main advantage of 3 tier system is that all business logic can be defined once within the business layer and then shared by any number of components within the presentation layer. Any changes to business rules can therefore be made in one place and be instantly available throughout the whole application.

It is possible to change the contents of any one of tiers (layers) without having to make corresponding changes in any of the others

Enables parallel development of the different tiers of the application.

Complex application rules easy to implement in application server. Easy to implement changes

Fewer JavaScript, thus simpler to the client

Superior performance for medium to high volume environments

Some of the disadvantages are;

There is more processing on the web server,

It does not interact with the WMS server directly.

More complex structure

More difficult to setup and maintain The physical separation of application servers containing business logic functions and database servers containing databases may moderately affect performance

Answer 2

I hope these are the right answers:

The benefits of the N-tier model are as follows:

• Scalability: The key N-tier benefit is improved scalability since the application servers can be deployed on many machines. Also, the database no longer requires a connection from every client -- it only requires connections from a smaller number of application servers. In addition, TP monitors or ORBs can be used to balance loads and dynamically manage the number of application server(s) available.
• Better Re-use: The same logic can be initiated from many clients or applications. If an object standard like COM/DCOM or CORBA is employed (as discussed in tool dependence), then the specific language implementation of the middle tier can be made transparent.
• Improved Data Integrity: since all updates go through the middle tier, the middle tier can ensure that only valid data is allowed to be updated in the database and the risk of a rogue client application corrupting data is removed.
• Improved Security: Security is improved since it can be implemented at multiple levels (not just the database). Security can be granted on a service-by-service basis. Since the client does not have direct access to the database, it is more difficult for a client to obtain unauthorized data. Business logic is generally more secure since it is placed on a more secure central server.
• Reduced Distribution: Changes to business logic only need to be updated on the application servers and do not have to be distributed to all the clients.
• Improved Availability: mission-critical applications can make use of redundant application servers and redundant database servers. With redundant servers, it is possible to architect an application so that it can recover from network or server failures.
• Hidden Database Structure: since the actual structure of the database is hidden from the caller, it is possible that many database changes can be made transparently. Therefore, a service in the middle tier that exchanges information/data with other applications could retain its original interface while the underlying database structure was enhanced during a new application release.