What's the Purpose of the Network?

This chapter covers the following topics:

• Business Applications: This section covers business applications and the associated network design elements for them.

• Service Models: This section covers the different service models, how to leverage them, and what the network design characteristics are for each model.

• The Cloud: This section covers the cloud in all its forms and the associated network design elements.

• Data Management: This section covers data and the data management methodologies that will help every network designer make better design decisions.

What’s the purpose of the network? Why do we need a network? Why is a network there in the first place? These questions should always be at the top of your mind as network designer because understanding the purpose and goal of the network is critical to properly designing it.

As we answer these questions, a technical (and potentially a tactical) answer is that the network’s purpose is to get data from point A to point B in the right amount of time. This is a generally good answer to these questions, and usually network engineers, not network designers, can easily identify.

From a network design perspective, we need to take this answer a step further. Why is the network transferring data in the first place? To meet the business outcomes and objectives…to make the business successful!

Businesses have become so reliant on networks that the required availability of the network and its associated services has to be designed at an extremely high level. This is similar to what transpired with the plain old telephone service (POTS) network. It became so relied upon that the overall availability had to be designed at an extremely high level.

There is a shift in the network, as discussed in the previous chapters, toward a service-focused network. When we talk about services in this context, we are talking about applications, service models, the cloud in all its forms, and data.

This chapter covers the following “CCDE v3.0 Unified Exam Topics” section:

• 4.0 Service Design

“Do I Know This Already?” Quiz

The “Do I Know This Already?” quiz allows you to assess whether you should read this entire chapter thoroughly or jump to the “Exam Preparation Tasks” section. If you are in doubt about your answers to these questions or your own assessment of your knowledge of the topics, read the entire chapter. Table 3-1 lists the major headings in this chapter and their corresponding “Do I Know This Already?” quiz questions. You can find the answers in Appendix A, “Answers to the ‘Do I Know This Already?’ Quizzes.”

Table 3-1 “Do I Know This Already?” Section-to-Question Mapping

1. Which of the following options is the correct application model for the statement “This is the simplest application model and it is equivalent to running the application on a personal computer”?

1. 3-tier model

2. Single-server model

3. 2-tier model

4. SaaS

2. Which of the following application models is like the client/server architecture?

1. 3-tier model

2. Single-server model

3. 2-tier model

4. SaaS

3. Which of the following application models has web, application, and database layers?

1. 3-tier model

2. Single-server model

3. 2-tier model

4. SaaS

4. Which service model is best used when a business requires full control of all components within an application?

1. PaaS

2. IaaS

3. SaaS

4. On-premises

5. Which service model is best for application developers?

1. PaaS

2. IaaS

3. SaaS

4. On-premises

6. Which service model is best if a business wants complete control over its virtual infrastructure but also wants to operate on a pay-as-you-go basis?

1. PaaS

2. IaaS

3. SaaS

4. On-premises

7. Which service model is best if a business wants an application to run with ensured availability but doesn’t want the headache of managing the application in any form?

1. PaaS

2. IaaS

3. SaaS

4. On-premises

8. Which cloud type has the highest cost?

1. Hybrid cloud

2. Private cloud

3. Multi-cloud

4. Public cloud

9. Which cloud type is best if a business wants the most control possible?

1. Hybrid cloud

2. Private cloud

3. Multi-cloud

4. Public cloud

10. Which cloud type is best if a business wants to ease into a cloud computing environment over a long period of time?

1. Hybrid cloud

2. Private cloud

3. Multi-cloud

4. Public cloud

11. Which option is the proper data management pillar for the definition “The planning of all aspects of data management”?

1. Data quality

2. Data governance

3. Data architecture

4. Data security

Foundation Topics