CCDE: Come TogetherThe intersection of the design use cases and the design lifecycle on CCDE

 

This article builds upon 2 series of articles I’ve previously written, the first series covering the Design Lifecycle (Book of Questions, Now What? and Rock & Roll-out), and the second series covering the Design Use Cases (Parts 1, 2 and 3). Each series separately covered two of the three dimensions of the CCDE practical exam. Now I want to put it all together, and this article aims to touch upon the considerations and constraints at the intersection of a network design use case and a network design lifecycle phase. Take a look at the table below. Please observe not all considerations and constraints will be applicable to all design situations. Pay special attention to the items in bold, as they are very important for the specific design lifecycle and use case combination.

 

Elicit RequirementsCreate DesignsCreate an Implementation PlanValidate & Optimize Design
Add/Replace Technology, Service or Application

. Drivers for redesign

. Desired business outcomes

. Industry-specific regulatory constraints

. Preferred vendors or technologies

. Timelines and milestones

. Customer's tolerance to risk

. Baseline

. Budget and cost-benefit analysis

. Prioritized desired characteristics (scalability, speed, availability, security, manageability)

. Customer locations and available connectivity options

. Are there best practices or CVDs available? Adapt them to your situation

. Be open-minded, think outside the box to come up with different solutions

. Compare and contrast different solutions vs. the elicited requirements within constraints

. Seek to compromise, if no solution meets ALL stated requirements

. Determine new technology, service or application needs

. Determine conflicts with remaining technologies, services and applications in the network.

. Determine the technology footprint

. Determine where the new application will be hosted, and how the consumers of that application will access it

. Consider serviceability and be future-looking

. Determine deployment impact

. Determine the implementation steps

. Create and execute a comprehensive testing plan as you pilot the solution

. Make adjustments as necessary

. Update the documentation and create a baseline

Merge/Divest

. Desired business outcomes

. Industry-specific regulatory constraints

. Preferred vendors or technologies

. Timelines and milestones

. Who the key stakeholders are

. Customer's tolerance to risk

. Budget and cost-benefit analysis

. Prioritized long-term desired characteristics (scalability, speed, availability, security, manageability)

. Customer locations and available connectivity options

. Plan for a phased approach, starting with quick & dirty connectivity

. Are there best practices or CVDs available? Adapt them to your situation

. Determine what to keep and what not to keep

. Determine the implementation steps

. Make adjustments as necessary

. Create the documentation and a baseline for the new merged or divested networks

Scaling

. Planned growth (or not) and capacity planning

. Preferred vendors or technologies

. Timelines and milestones

. Baseline

. Budget and cost-benefit analysis

. Customer locations and available connectivity options

. Are there best practices or CVDs available? Adapt them to your situation.

. Be open-minded, think outside the box to come up with different solutions

. Compare and contrast different solutions vs. the elicited requirements within constraints

. Standardize on a solution per branch type or technology footprint

. Design with future growth in mind, both planned and organic

. Determine deployment impact.

. Determine the implementation steps.

. Make adjustments as necessary.

. Create and execute a comprehensive testing plan as you pilot the solution and as much as possible estimate the impact when the solution is deployed to all sites

. Update the documentation and create a baseline.

Design Failure

. Pain points

. Troubleshooting is one of the inputs to design failure re-designs

. Industry-specific regulatory constraints

. Baseline and documentation

. Budget

. Do a root-cause analysis

. Documentation will help: topologies, placement of services, security policies, traffic patterns, application requirements, NMS, SLAs, etc.

n/a

. Make adjustments as necessary and observe whether the problem was solved.

. Create and execute a comprehensive testing plan as you pilot the solution, if possible.

. Update the documentation and create a baseline.

Greenfield

. Desired business outcomes

. Industry-specific regulatory constraints

. Preferred vendors or technologies

. Timelines and milestones

. Customer's tolerance to risk

. Budget and cost-benefit analysis

. Prioritized desired characteristics (scalability, speed, availability, security, manageability)

. Customer locations and available connectivity options

. Are there best practices or CVDs available? Adapt them to your situation

. Be open-minded, think outside the box to come up with different solutions

. Compare and contrast different solutions vs. the elicited requirements within constraints

. Seek to compromise if no solution meets ALL stated requirements

. Start off on the right foot by considering all principles of good design: scalability through modularity; speed; availability through reliability, redundancy, convergence, resiliency and serviceability; security and manageability

. If you're starting over, do lessons learned

n/a

. Create and execute a comprehensive testing plan, especially if you are starting over

. Make adjustments as necessary

. Create documentation and a baseline

 

 

When taking the CCDE practical exam or on real-life network design situations, this table can provide you a framework for considerations and constraints you may encounter and you can do a mental checklist so that you don’t miss anything.

 

Did you miss any considerations or constraints on this blog? Is there a topic you want to hear about on my upcoming blogs? Add it to the comments field!

 

pic Elaine Lopes3.PNG

 

 

Elaine Lopes is the CCDE and CCAr Certifications Program Manager and Team Lead for the CCIE program team, and she’s passionate about how lives can change for the better through education and certification.

 

 

 

 

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