Network design engineers are the backbone of the internetworking world. They are the people responsible for turning concepts into designs. They must take the customer's requirements, budget, and plans for growth and apply design principles to turn ideas into reality. They quietly do this while claiming none of the credit. Designing networks is one of the most challenging and rewarding careers a network engineer can choose. You will have to forge close links with vendors and your customers, and deal with installation engineers on a daily basis as they turn your designs into live networks through installation, testing, and handover phases. The Cisco Certified Design Engineer (CCDA) is your first qualification on the road to becoming a Cisco Certified Design Expert, which holds the same, if not more, prestige as the famous Cisco Certified Internetwork Expert credential. If you choose to add hands-on qualifications such as CCNA and CCNP to your portfolio of skills, you will be in a unique position to see the network take shape, from planning and design to the final build. You will also be in very high demand by employers or as a consultant. This manual has been written by an expert Cisco engineer who has several years of experience as an employee and as a consultant designing and troubleshooting large corporate networks at an enterprise level. This guide will teach you everything you need to master in order to pass your Designing for Cisco Internetwork Solutions (DESGN) v2.1 (640-864 DESGN) exam, including: - The OSI model - Network design methodology - The Cisco enterprise architecture model - Enterprise LAN and data center design - Enterprise WAN design - IPv4 and Ipv6 addressing and transition - Designing with OSPF, EIGRP, and BGP - Network security design - Voice and video design - Wireless design considerations - And much more For ten years, the Simplified range of IT study manuals have been helping students to pass their exams and get ahead in the world of internetworking. Whether you want to make a career change into the world of IT or to progress in your current job - or perhaps enter the exciting world of consulting - this guide will help you. Every day, people all over the world are passing their exams and getting jobs they never dreamed possible thanks to the Simplified study guides. We look forward to hearing your success story. About the Author Daniel Gheorghe is a CCIE (31995) in Routing and Switching. He is currently preparing for his second CCIE certification (in Security) and he is developing his skills in system penetration testing. He also holds numerous certifications in networking and security, from Cisco and other vendors, including CCNA, CCDA, CCNA Security, CCNP, CCDP, CCIP, FCNSA, FCNSP, and CEH. He took an interest in IT at an early age and soon developed a passion for computer networking, which made him study hard in order to reach an expert level. Daniel has worked for different Cisco Partners and System Integrators in Romania in system design, implementation, and troubleshooting for enterprise-level networks. He is also involved in several international freelance consulting projects in his area of expertise.