What Should I Study?
This is a question that is posed to everyone who is successful, and each one has a different take on it. Clearly you need to be proficient in the blueprint topics, but if there is one thing you should spend significant time on, I would say Layer 3. You need to know open standard routing protocols inside and out—which one would be suitable for a particular application and which one wouldn’t, how it affects the design if you need to modify areas and zones, how to create failure domains and summarize, and so on. Unfortunately, there is no single book to read. Remember, Cisco expects you to be operating as an architect/designer and have multiple years of experience.
The following list should provide insight into where you should consider investing your study time:
Cisco Live: Attend the CCDE Tectorial to attempt an example lab during the session and search for design sessions, including areas of technology where you are your weakest. If you cannot attend in person, watch the videos to get the most from the recorded sessions (you will always learn more than you would by just reading the presentations).
Cisco Press: Look for design-based publications and architecture. Anything from Russ White and Definitive MPLS Network Designs is a must due to the way the author presents the networks in a similar manner to how the scenarios in the exam are presented with background information.
Study groups: Form your own study group or see if you can join an existing one in order to discuss technologies or work through labs you have purchased together. Also, you can discuss methodologies/technology choices, offer to discuss your area of expertise, and learn from others discussing theirs.
Cisco-validated designs: Read up on designs for different network zones, learn why a design is being recommended, and think about scalability, manageability, speeds and feeds, failure domains, and convergence.
Unleashing CCDE: Read blogs created by the CCDE team and CCDEs in the community. Aim to write one yourself when you have passed!
Bootcamps: If you still feel you aren’t ready, there are legitimate vendors operating in this space. Ask the community for advice to see which may offer the best value for you based on your own background.
Remember, gaining the CCDE is a journey. It’s going to take time, and you might not be successful initially.