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Cisco CCDE v3 Training

71:39:25 Hours
226 Lectures


Network Design Fundamentals Course

02:28:37 Hours
17 Lectures


Cisco CCIE Service Provider Training

96:02:27 Hours
242 Lectures


Network Design Best Practices – Simplicity

Network Design should be simple! Simplicity is the first network design best practice that I want you to remember. If you have been in the field long enough, you have probably heard about the KISS principle. If you are a regular follower of my blog, you have maybe heard about the SUCK principle as well.   KISS stands for Keep It Simple Stupid.

But do you really know what the simple part is ? Can every part of the network be a simple ? Unfortunately NOT ! It just cannot be ! But still you should on simplifying as much of your network as possible.   As I have indicated in the past here, intelligence should be at the edge of the networks and network core should be as simple as possible. If you read the above article, you will see some examples. ( There are different opinions about the place of simplicity in networks.

Some researchers believe that if the core has some intelligence the overall network complexity is reduced ).   Networks have many protocols, technologies. Understanding each of them might be easy but interaction between them creates complexity. In my CCDE training sessions, I like to give the Pepper and Salt example to explain this point.

Which one is salt and which one is pepper ? It needs to be so simple for a basic object, doesn’t it ?But I almost always confuse this ! Network design is exactly the same. There are many technologies that interact with each other. Although each one might be simple,the end result may not be so simple to predict.

You summarize the prefixes in one place of the network, and you create sub optimality in another place. You enable a new feature,such as IPv6 or Multicast, in one part of the network and the result is that you open the network to a lot of new security attacks. Those features were needed for robustness, but they create fragility. You may not see the impact immediately but it can be huge. This is known as Butterfly Effect in design.

A butterfly flapping its wings in South America can affect the weather in Central Park. This is the first post of the Network Design Rules series that I decided to share with my blog readers. Thanks for reading and please share your thoughts in the comment box below.

Created by
Orhan Ergun

Orhan Ergun, CCIE/CCDE Trainer, Author of Many Networking Books, Network Design Advisor, and Cisco Champion 2019/2020/2021

He created OrhanErgun.Net 10 years ago and has been serving the IT industry with his renowned and awarded training.

Wrote many books, mostly on Network Design, joined many IETF RFCs, gave Public talks at many Forums, and mentored thousands of his students.  

Today, with his carefully selected instructors, OrhanErgun.Net is providing IT courses to tens of thousands of IT engineers. 

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