Upgrade Example

Suppose you have written a LayGO application for Linux, using the X.25 protocol and a 1 line synchronous communications controller supporting 56 kbps. Now you are asked to port your application to run under Windows 9x, and to upgrade your communication board to support multiple lines. And Frame Relay at full T1 speed will replace X.25. Of course, they want it done yesterday!

1. Changing to Windows 9x requires that you install a VxD for the new board and LayGO dynamically linked library with Frame Relay support. Since the LayGO API is the same under Linux and Windows, no changes regarding API are required.
2. To change from X.25 to a Frame Relay device, you need to edit the LayGO service data base to include the new Frame Relay services.
3. To change the communication hardware you need to edit the SDLC hardware and physical layer configurations of your LayGO devices.
4. If your communication board and T1 line speed tests have been passed, you are ready to test the Frame Relay devices.

In this example, you changed modules in all three classes: operating system, hardware and protocol. Of course, you may just change the OS or the board, or you may want to add Frame Relay while retaining your X.25 services.

This modularity, accomplished through software and hardware encapsulation and standardization, ensures that today's software investment is long-term and is not rendered obsolete by changing technology.