Once I decided for the CCDE exam I was thinking it is a hard challenge but surprisingly I will say it is not as much as you think.This is good news and you started to smile ? Hope once you finished the article you continue to it 🙂
Yes it is not since I believe that success of this exam is acting for the exam. Playing the game with their rules. Although it is hard if not impossible you should know all the best practices for all the CCDE blueprint topics, you have to consider always customer’s business and technical requirements in the exam.If you go blindly with all the best practices you will fail !. In this post I will give examples to show how you should think for the exam sometimes even a little different than real life design.
For example you can design a flat OSPF domain for your topology if it fits, you consider generally router LSA for MTU , low performance routers to not to effect fast and robust device ( your domain will converge based on your weakest device) , flooding domain size and so on. But in the exam you may face that customer requirements might push you to put only up to 30 routers in one area or low performance routers into the NSSA or stubby area.
Without breaking NDA I will try to give these kind of examples as much as I can while keeping article within acceptable range
Customer may want to carry layer2 traffic over layer3. You can do it in a lot of ways such as with OTV , LISP, MPLS VPN so on. Based on other specific requirement such as mpls support of the devices or maybe least amount of configuration you should reduce the options and find the best one for your customer. I remember that one time Brian McGahan told me that sometimes all the answers for the specific question might be true but they want us to choose the best one. I agree in general !.
For very low latency, switching solutions may force you to compare between Cut-through and Store and forward you should choose Cut-through switching if the criteria is only low latency.From all these examples we understand that only knowing the technology is not enough , also you should analyze the technologies and decide the best fit for the case.
For very high scale multicast deployment , if the memory is a problem or application run between many sites then you should know that best multicast protocol is the Pim-Bidir. From this example you may understand that this exam is different than operation based exam such as CCIE , JNCIE so on.
Customer requirements may force you to choose fast reroute technology rather than fast convergence technology. You may think that best choice is the MPLS Traffic Engineering fast reroute but customer may not be running MPLS on their network so LFA is one of your choice. If you cannot cover every router in your topology with the LFA, and coverage is critical then remote LFA might be the best choice.
Depending on customer requirements and time constraint for the deployment you may choose to deploy your design for IPv6 from edge to core or core to edge, so you should know the drawbacks of both designs.
You should know where and why you deploy specific QoS feature for IP and MPLS traffic. For example you should know that generally you deploy shaping at the customer site since service provider deploy policing at their inbound interface.
You should know that MPLS L3Vpn is the best scale , equal to TDM and ATM from security point of view, need specific type of technology for multicast such as Rosen Gre ,mLdp so on. Technology knowledge is the key, buzzwords and basic design principles should be known very well.
From my experience timing is not a problem for the exam. But for the real life it is not realistic. After talking with all my CCDE friends , one thing is common that in real life reading and understanding 30 to 35 real problems , understanding all the background informations and deciding the best one within 2 hours is hard and not realistic.
It is truly a design based exam , there is no configuration , implementation type of questions. You may know how to implement IPSEC VPN for the Getvpn but if you don’t know that you have to use Getvpn for private networks ( including MPLS VPN) not for the public networks then probably you should continue to study…
You will be challenged from almost all blueprint topics , so good preparation is the key. If you are CCIE Service Provider and updated with the all topic then you should focus all the topics from the design point of view. For example you may know how to configure IS-IS but if you don’t know that IS-IS can not work with pure IPSEC tunnel , then you can not choose suitable tunnel type for your IGP.
I will not write about specific Ciscolive video, training video since I liked Jeremy Filiben’s update for those resources , you can reach those resources from here and start to study. Also you can take a look at my Twitter account since I updated my recommended Ciscolive videos there. My twitter account is @OrhanErgunCCDE.
But still I’d like to tell you about some specific books which I see as very useful for CCDE exam.
- Optimal Routing Design is very relevant and full of design advice and examples. This is important book not only for the exam but also for your daily design decisions.
- CCDP Arch- Even it seems for CCDP , very relevant with the exam and updated with the latest best practices. Even if you don’t go for the CCDE, you should read this book , or maybe some specific areas of the book.
- MPLS Enabled Application 3rd edition- This book should be read after completing all your MPLS study, but definitely before exam.
- Definitive MPLS Design – I like this book , very good MPLS design examples , very realistic but I don’t think it is relevant with the exam. Exam is higher level , not too much deep technical knowledge. As an example you should know MPLS Qos models such as Uniform and Pipe modes but not how to implement and all the differences between short and long pipe.
- And lastly , The Art of Network Architecture- This book did not come out yet, it will be published by end of April.Russ White and Denise Donohue made a good job , I reviewed it and it’s full of design principles, somehow relevant with the exam but overall this book is the best one for the general network design concepts. Also you can listen my packetpushers podcast from here where I gave my comments about this book.
Conclusion: For the designer you should follow the best designer since design is very objective decision , you should read the right books , watch updated videos since technology evolve very fast and so on. For the exam, you should focus on the customer requirements, know the technology , not bits and bytes but from the design point of view.
CCDE is very popular, hard exam, very low success rate even for the multiple times CCIEs but if you feel ready , go and try !. If you want to pass at your first attempt then don’t forget to consider customer requirements first, not the best practices, don’t rush at the exam since time is not a problem if you already know what you are doing. If you liked the examples in the article please write your comment below and I can try to write another posts to give much more examples.