• Dividing the complex network operation into more manageable layers.
• Changing one layer without having to change all layers. This allows application developers to specialize in design and development.
• Defining the standard interface for the "plug-and-play" multivendor integration.
  

Continue reading ...

OSI (Open System Interconnection) - in 1970 by International Organization for Standardization (ISO)
- this was meant to help vendors create interoparable network devices.
- this is the primary architectural model for networks.

Layered Model

CISCO three-layer hierarchial model
-three layer model that is used to help design,implement and maintain any size networks.

Continue reading ...