Sep
26

Practical Exam Overview

The practical test is a series of design scenarios. At the beginning of every scenario, you are given the existing network design information (diagrams, background, applications, business plans etc). After this, you are presented with a particular technical problem - e.g. a problem in the existing design that you need to fix, or a requirement to scale the existing network, or possibly a scenario where you have to spin off another network from existing one. You are then being asked a series of questions to shape your solution, justify it and possibly solve additional problems. You will have to read alot, process and co-relate the information and apply some analysis skills to come with an optimum solution. Reading, extracting key features and co-relating are probably the main skills you need to posses in addition to knowing the technologies. There are three major network topologies and two scenarios for every network. The networks feature the use of EIGRP, OSPF, BGP and ISIS routing protocols, along with MPLS and other tunneling techniques. Nothing that is Cisco-specific (besides using EIGRP in some scenarios) - you will not have to select the hardware or calculate bandwidth points - the exam is very generic and focused around abstractions. You may find more detailed desription of the practical exam here along with a reading list I made over a year ago.

I would also recommend you getting your hands around the CCDE techtorial presentations made at Cisco Live! last two years, as those provide some interesting insights on the exam. Unfortunately, the presentations are not available to general public, and sharing them would be violating Cisco's copyright. Your best is trying to ask you friends at Cisco SE teams for the documents, if you want to get them "legally". However, even if you can't get those documents, do not despair and make sure you tried the CCDE practical demo at https://learningnetwork.cisco.com/docs/DOC-2438. This demonstration does have some wrong answers, but still gives you a goode idea of how the practical exam looks like.

As for the "ultimate" reading list, I've been publishing some before in CCDE certification and CCDE Written. Since then, I made some major updates to these. The below compilation is made of some "core-reading" books along with numerous short publications which I recommend reading to prepare to the practical test. Remember

Fundamentals

Core Routing Knowledge

Core knowledge for the exam is covered in a few books. Some of these books are written by Russ White and Alvaro Retana, who are among the CCDE exam designers.

  • IS-IS: Deployment in IP Networks by Russ White and Alvaro Retana. Good reading on ISIS, provides some design ideas and covers advanced topics.
  • OSPF: Anatomy of an Internet Routing Protocol by John Moy. Provides detailed OSPF overview from the protocol author, covers historical perspectives and additional information.
  • EIGRP for IP: Basic Operation and Configuration by Russ White and Alvaro Retana. Good reading on EIGRP network designs.
  • BGP Design and Implementation by Randy Zhang Excellent Reading on BGP, missing some "new" features such as BGP next-hop tracking, but perfect for advanced BGP understanding.
  • OSPF and ISIS: Choosing an IGP for Large Scale Network by Jeff Doyle. Optional. Excellent additional reading on OSPF and ISIS and routed network design.
  • Routing TCP/IP Volume II by Jeff Doyle (Multicast sections). This book provides excellent Multicast routing overview. Read over Chapters 5-7, and possibly Chapter 4 (NAT). Multicast is not huge in CCDE, but you definitely need to know it.
  • Optimum Routing Designs by Russ White and Alvaro Retana. You may mainly concentrate on IGP protocols designs and IGP-specific appendices (Part I, Part II and Appendix A-E). I recommend reading this book after you have completed the previous ones on the list.
  • Understanding Third-Party Next-HopThird-party next-hops are not very well explained in other publications, so reading this publication may help.
  • EIGRP Query ScopingA short summary on EIGRP query scoping, which is they key to EIGRP scalability
  • OSPF Transit Capability An overview of powerful transit capability feature of OSPF protocol which makes it possible to use complex area hierarchices and perform topology information aggregation with OSPF

You may notice that wonderful Alex Zinin's and Radia Perlman's masterpieces are missing from this list now. The sole reason I took them away is their "grand" status - carefully reading every of these books along may take you months. However, if you feel like all time is yours, feel free to add "IP Routing" and "Interconnections" to your reading list.

VPNs and Other MPLS Applications

Knowing MPLS applications, such as VPNs and TE is crucial to passing the CCDE exam. There is a ton of books available on MPLS VPNs, so I tried to select just a minimal reading list on the subject.

  • MPLS Enabled Applications by Ina Minei et al. One of the best introductions to MPLS services, features a lot of self-study questions, perfect for preparing to CCDE.
  • Layer 2 VPN Architectures by by Dmitry Bokotey Perfect introduction to L2 VPNs, complements the previous book.
  • Advanced MPLS Design and Implementation by Vivek Alwyan Optional, you could skip configuration portions and some ATM related topics. Of course, do not get stuck in the configurations - you will not need them in the design exam.
High Availability

The following is a small reading list on the subject. High Availability is a complex topic, which could hardly be covered in a single document.

IPv6

IPv6 is not a big topic in the CCDE exam. Mostly because it is not widely deployed, however the other important reason is that IPv6 routing is very similar to IPv4 - the only difference is the access-layer. Nonetheless, knowing IPv6 fundamentals is important for overall education.

Security

Security is not the primary topic of the CCDE exam, but you should solid understanding of the concepts. The reading list below focues mainly on SP-related security topics, routing security and infrastructure protection.

Quality of Service

Just like Security, QoS is not big in the CCDE exam. However, do not take it easy. You need to know QoS fundamentals, models and tools by heart to pass the exam. In addition to generic QoS reading, I added some "TCP related" publications, as TCP is the major transport protocol of the Internet, and knowing QoS considerations for TCP is important.

  • TCP Performance
  • Future for TCP
  • IP Quality of Service by Srinivas Vegesna. This book may lack some configuration examples and does not cover every Cisco QoS tool but provides good QoS background.
  • RFC 2475 - An Architecture for Differentiated Services. A must-read document to understand the Diff-Serv architecture.

What to read last two months before the exam

The below list is an addition to the list you have seen previously. You goal is comparing and analyzing technology properties, abstracting and getting a high-level view of protocols and solutions.

  • Definitive MPLS Network Designs by Jim Guichard et al. *Definitely*, your number handbook when preparing to the practical exam.
  • Optimum Routing Designs by Russ White and Alvaro Retana. Review Part I/Part II and see if you understand the topics better
  • RFC 1958 and RFC 3439 These are important! The documents cover some of the Internet architectural guidelines. These documents require careful reading and provide some very helpful insights into network design.
  • Leonard Kleinrock "Hierarchical Routing for Large Networks".This paper outlines the core of modern routing protocols - hierarchical addressing and routing principles.
  • Robustness and the Internet, Theoretical Foundation A must read document on complex systems and their evolution
  • MPLS-TE Does Not Scale by Adrian Farrel If you think MPLS-TE is perfect, look over this presentation.
  • RFC 4655: A Path Computation Element Based Architecture. This document provides an interesting alternative to decentralized traffic engineering commonly used in modern networks. Also mentioned in the "Definitive MPLS Network Designs".
  • Scaling Considerations in MPLS Networks by Ina Minei . An excellent presentation that outlines some scaling problems in MPLS networks.
  • MPLS TE Scaling Analysis, Yasukawa, Farrel Some good reading on MPLS TE scaling properties and possible solutions.
  • RFC 4206: LSP Hierarchy. Introduces hierarchical LSP into MPLS. You do not have to read the whole document, but you need to have a general understanding on hierarchical LSPs.
  • Scaling MPLS Networks This paper summarizes known approaches to MPLS network scaling.
  • Introduction to Compact Routing. Provides insights on the limitations of hierarchical routing and possible solutions to the problem.
  • Internet Traffic Engineering by Optimizing OSPF Weights An alternate approach to traffic engineering that using OSPF metric manipulations solely and achieves nearly optimum performance.
  • Understanding Unequal-Cost Load-Balancing An overview of unequal cost load-balancing with EIGRP

Misc topics

The below topics do not necessary fall under the CCDE blueprint, but, in my opinion, represent interesting reading. It never hurth to do some additional reading that helps generalizing some ideas and getting a better perspective of network design.

Subscribe to INE Blog Updates