How is “Application Layer” different from “Transport Layer” of the TCP Network Model?

Question

Q. How is "Application Layer" different from "Transport Layer" of the TCP Network Model?

I am a student learning about the basics of networked programs. This was one of the questions given in the assignment which I can't explain clearly.

I do understand the concept of each layer and what it does in the model, but how could I compare and explain the differences between the Applicaiton Layer and the Transport Layer?

Thank you.

Answer 1

Transport is the act of moving data between two end points (think the "TCP" in TCP/IP). The application layer is the application that makes use of that transport (think HTTP or FTP, for example).

See http://en.wikipedia.org/wiki/OSI_model for more info.

Answer 2

It is quite simple.

Transport Layer - transmit the data between two ends. So, It take care of lots of thing, such as Retransmission of data if it fails at previous attempt, flow control, error control. You should know the difference between the error control by Transport Layer and DLL.(google for it).

Application Layer - It is near to user-end. User interacts to the network through Application Layer. Say HTTP Protocol. Application Layer define a rule to the end user about the communication data through the internet. It is more software oriented.

As a Lay You think that Application Layer Define or set the rule for the data transmission, identify the end partner etc (You can search what HTTP does?) and give the data to lower layers And finally Transport layer take care of sending this data to the network.