CCNA Routing and Switching Complete Study Guide, 2ed: Exam 100-105, Exam 200-105, Exam 200-125 About the Author Todd Lammle , Cisco certified in almost every category, is the authority on Cisco networking and certification. His three decades of real-world experience is prevalent in his writing. He is an experienced networking engineer with very practical experience working on the largest bounded and unbounded networks in the world at such companies as Xerox, Hughes Aircraft, Texaco, AAA, Cisco and Toshiba, among many others.