As networks grow and technology becomes more complex, IT departments have begun looking for ways to simplify support for their systems. One method is to standardize on a single networking protocol. A Telnet client attaches to a Telnet server on the mainframe. Since the client is attaching via Telnet, that is where and how session services will be supported. Assume that your goal is to enable your end users to run their SNA applications without any loss of functionality via TN3270, the standard for 3270 sessions over Telnet.
File transfer is an important element of any distributed processing system.
This function not only provides the means to identify and transfer the file, but also deals with the file structure differences between the PC and the mainframe platforms. If you're in the financial industry where, for instance, a broker needs confirmation that a stock buy order has been received, this is critical. It's also important to payroll departments, which have to be sure that checks are printed. The key unbinds the user from one application and leaves the connection open for requesting another application. Keeping the connection alive while the user switches from application to application gives the user more control and saves time.