# Connection between OSI and IPS models

The OSI model was originally invented when the main computers were mainframes. Making layer 5 more important; however, in modern applications the roles and responsibilities of the last 3 layers in the OSI get very mixed and end up being combined into one another. Some applications might not implement some of them.

For example HTTP uses cookies for layer 5 , extended ASCII for layer 6 , and commands for layer 7 . Whereas FTP doesn’t have a way to implement layer 5 , uses the same extended ASCII for layer 6 but different commands for layer 7 .

This mix of these layers is normally dependent on the protocol - so normally rolled up into one thing.