By day, Mark A. Sportack is the director of network engineering for ClearBlue Technologies. His professional responsibilities include setting technical direction for data networks within the company's Internet data centers, network planning and design, capacity management, and network security. By night, Mark is an adjunct professor with Syracuse University's School of Information Studies and Technology, where he teaches graduate courses on data networking. During the course of the last 20 years, Mark has worked in virtually every aspect of Information Technology, from administering networks and servers to managing technology and technical personnel. Mark has also written a variety of books, including IP Routing Fundamentals published by Cisco Press, Networking Essentials Unleashed, and many others.