Marwan Al-shawi, CCDE No. 20130066, is a Cisco Press author whose titles include the top Cisco certification design books CCDE Study Guide and Designing for Cisco Network Service Architectures (ARCH) Foundation Learning Guide, Fourth Edition. He also is an experienced technical architect. Marwan has been in the networking industry for more than 12 years and has been involved in architecting, designing, and implementing various large-scale networks, some of which are global service provider—grade networks. Marwan holds a Master of Science degree in internetworking from the University of Technology, Sydney. He enjoys helping and assessing network designs and architectures; therefore, he was selected as a Cisco Designated VIP by the Cisco Support Community (CSC) (official Cisco Systems forums) in 2012 and by the Solutions and Architectures subcommunity in 2014. In addition, Marwan was selected as a member of the Cisco Champions program in 2015 and 2016. In his spare time, Marwan provides CCDP- and CCDE-related training and blogs at netdesignarena.com. André Laurent, 3xCCIE No. 21840, CCDE No. 20120024, is the worldwide director of engineering for enterprise networking sales at Cisco Systems and a Cisco Press author. Outside his own personal development, André has an equal passion for helping others develop their systems and assisting them with the certification process. André is recognized in the industry as a subject matter expert in the areas of routing, switching, security, and design. Although he wears a Cisco badge, André takes a neutral approach in helping clients establish a long-term business and technology vision covering necessary strategy, execution, and metrics for measuring impact.