Hi Ramesh,
There are seven layers to the OSI model. These layers are:
Application -- Layer 7
Presentation -- Layer 6
Session -- Layer 5
TCP/IP -- Layer 4
Network -- Layer 3
Data Link -- Layer 2
Physical -- Layer 1
These layers are easy to remember if you use this anagram: Please Do Not Throw Sausage Pizza Away.
I hope this helped!
Eric Mann