While using TELNET or FTP, the highest layer that one can use to transmit the data is the Application Layer…

Well, knowing in brief what exactly an application layer is…

It basically defines the functioning of the application processes including both servers and the client, where

they exchange messages among themselves and processing on the distinct end systems. Thus, precisely an ALP defines:

• Distinct types of messages such as response messages and request messages
• Messages syntax and its types which states the field limn and the fields in the messages
• The fields semantics which states that the meaning of the information that is been the part of that field
• Precedent for the determination of how and when a process sends and react to messages

Hope, this would have helped you out with your query...

All The Best!