After completing the network design, you need to save it. For this purpose, select the "Save Configuration" from the File Menu. Note that the "saved file" and "exported file" have different file extensions and not the same. A save file can only be opened and used in the network designer. An exported file can only be used by the network simulator. The saved network diagram has an extension of .dgm. Note that for doing any changes to the layout of the network diagram at a later stage, you need to have a saved version of the file.

On selecting the Save Configuration option you will be prompted for the name of the file under which this Configuration has to be saved. Enter the file name and click on "Save" button. By default these files are stored in the user directory, you can also save the file under a different directory

Below figure shows the Designer with the Dialogue Box prompting for the user to type the Filename.

Alternatively, you will also be prompted to save the network diagram when go to File -> Exit. You have the option to save the network diagram at this stage. If you had already saved the file, just choose "No". Of course, selecting "Yes" will prompt to input the file name as described in the previous section.

NOTE: There should be atleast a single device to save the network or to export the network to Network Simulator. Selcting the "Save Configuration" from the "File Menu" or Clicking the "Export Configuration" menu without any device in the designer will give you a Warning Message.