H. . Tarish Haider and D. Halboot Mohussen, “Virtual Privet Networks using Cisco Routers”, J. eng. sustain. dev., vol. 13, no. 4, pp. 10–27, Dec. 2009, Accessed: Apr. 18, 2025. [Online]. Available: https://jeasd.uomustansiriyah.edu.iq/index.php/jeasd/article/view/1493