Hey everyone... think CCDE candidates or potential candidates are going to get a lot out of hearing from Cisco Press CCDE Study Guide author, Marwan Al-shawi. Here's his first blog. Hope you enjoy it. -Brett
In my previous post on LinkedIn – 1st CCDE Study Guide Book – I intended mainly to highlight and thank the experts who participated with their technical reviews and the sharing of their perspectives that helped largely to shape and enhance the contents. As I promised in that post, I am going to share my perspective regarding the CCDE study approach and how this book can help you to become a better network designer and prepare you for the CCDE Practical Exam. This topic will be covered over two blog parts, which will both collectively cover the main points with regard to the recommended approach to read this book and also help you start to “think like a designer”.
You may be wondering what makes the reading of this book different from other books or why you would need an approach rather than just reading every topic covered in this book!
Before answering this question, let’s see what makes reading or studying for network design topics different. First, I want to start by sharing my viewpoint regarding the phrase used in this book description, “Network design is an art”. What is the similarity between art and network design?
Normally with any type of art there is always a vision in any artistic work, and at the same time it is common for different people to interpret this vision or idea differently due to their different levels of understanding and varying points of view. In addition, if you ask two different artists to paint, for example, a painting for an idea or a topic, you will most likely get two different paintings that describe the same idea from each artist’s perspective.
Similarly with network design, if you ask two network designers to come up with a proposed network design for the same organization, you will probably not get identical designs. With that said, it does not mean one design is wrong and the other one is correct. Instead, this is like the art/painting example above, where each network designer has different level of understanding, experience, vision, etc. that all collectively drive the final design. This reminds me of a popular figure (Figure 1) shared in social media, if you ask three different people with different perspectives to describe the figure, you may get three different answers as following:
- The glass is 50% empty
- The glass is 50% full
- The glass is 100% full (50% water and 50% air)
In fact, all the answers are correct; however, the interpretation or philosophy of each person is different. In the same way, if we ask different network architects/designers to describe the network depicted in Figure 2 below, we will almost always get slightly different answers.
One network architect/designer might see this design as flexible due to the incorporated modularity, another network architect might see this design as having multiple single points of failure, and a third network architect may describe it as a scalable design with regard to the regional remote sites. This due to the fact that some designers/architects may focus on one perspective (limited vision - such as focusing on the technical aspect only) while others look at the big picture to see the different viewpoints, as illustrated in figure-3 (a modified version of a popular figure).
Therefore, like with art, network design is open-ended and cannot be limited to a single philosophy, training course, or approach. Having said that, in any artistic or creative field, like painting or music, the deeper the artist understands what he/she is observing or listening to, the better its meaning will be interpreted. This can always be improved by practice, reading relevant books, attending galleries, etc. Similarly, network designers/architects can still learn and enhance their design skills, experience, approaches, analytical thinking, etc. to have better insight into the art of network design and ultimately become better network designers/architects with business values always in mind. Taking these facts into consideration, CCDE Study Guide is designed to focus primarily on:
- How to analyze the different design requirements, e.g. business, application, technical, etc.
- How to think like a design engineer rather than implantation engineer
- How to link network and technical design to business priorities and goals (business-driven design)
- The current design options and applicable technologies “at the press time” and how to compare them from different design aspects
- The design considerations that may either provide advantages or introduce design constraints (depends on the requirements of the design scenario)
The primary goal of using this approach is to help you “improve” the following areas:
- Your understanding and analysis of different design requirements
- Linking technical design principles to business needs and values
- Your mindset to always think as a solution designer/architect rather than solution implementer
- Understanding of the different design options and considerations
- Your approach as a designer in a more structured manner
How to read this book (Author’s Perspective)
Disclaimer: this is only my suggested approach, and it’s up to you to use the desired approach that works best and is most comfortable for you.
How can you use this book to improve, expand, and enhance your network design logic and knowledge?
As highlighted above, each person has a different level of experience, understanding, vision, and technical knowledge. As such, it is impossible to suggest a single guideline for reading this book that will be applicable to everyone. Therefore, my suggestion in general is to set your own guideline that fits your knowledge, experience, and understanding. However, what can be offered is a generic approach that you can consider to benefit most from reading this book. This book in general covers a wide range of topics, and you are expected to have the foundational knowledge that pertains to the covered topics, as this book is not intended or designed to cover basic technical concepts. Taking this into consideration, you can use the following approach:
Whether you are planning your CCDE study or continuing your study (e.g. attempting the exam again), you should first go through each and every single topic briefly and highlight the covered topics and sub-topics that you are not familiar with the basics of (For example, how iBGP and eBGP technically work is out of this book scope and you are expected to have this foundational knowledge before reading any BGP-related topic. This book on the other hand, will focus on BGP design options, considerations, advantages, limitations, etc.). Then, read about these topics in more detail using your preferred resource such as the suggested reading sources at the end of each chapter, the CCDE recommended book list, or the relevant IETF RFCs/drafts integrated in each section.
Please note here you are not expected to read books. Instead, only read to understand certain topics based on the knowledge gaps you have identified. This way, you will ensure that your technical foundation will always support the design approach/thinking when you read the relevant topic and will help you to be a network design expert, ideally with knowledge and viewpoints that cover different angles. In other words, the more you read and discuss, the better you will become! Discuss!
Part 2 of this blog will discuss “how to think” like a network designer.