Middleware

1
Middleware

• What is middleware?
• A software interface glue that resides between
  the operating system (or network operating
  system) and the application in distributed
  client/server systems.

Server Application
Middle-ware
NOS
Physical NW Layers
2

• Vertical Integration
• Between layers in each stack
• Each layer interfaces with its neighbors
• Between application and middleware is the API
  Application Programming Interface
• Horizontal Integration
• Between equivalent layers located at client and
  server
• Middleware achieves horizontal integration
  between client and server middleware

3
Interfaces

• Middleware must be compatible with and interface
  with the network operating system
• Middleware must be able to interface with the API
• Compatibility issues

4
Middleware Tiers
2 Tier Middleware Architecture
Client Application
Middle-ware A
Middle-ware B
NOS
Physical NW Layers
5
Middleware Tiers
n-Tier Middleware Architecture (three tiers)
Application
Middle-ware A
ClientMiddle-ware
Middle-ware B
NOS
Physical NW Layers
6
Simple Example of n-Tiers
n-Tier Middleware Architecture (3-Tier)
Application
SQL server
ClientMiddle-ware HTML
VB
NOS
Physical NW Layers
7
N-Tier architecture

• Simplifies client software
• Development
• Configuration Maintenance fewer products
  protocols
• (true cost of computing includes ALL personnel
  support costs)
• Fewer client resources consumed (less memory and
  processing power)
• De-couples the development of the server systems
  from the client interface
• Facilitates platform independence