The fundamentals of network design are the essential elements that all network designers must understand and know how to apply. These elements ensure that the design is robust, efficient, and suitable for the organization's needs. Below are the main topics:

Requirements

The design requirements are the foundation for any network system. There are three main types:

• Functional: What the system must technologically achieve for the business, like sending VoIP traffic over specific links.

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  Note: A design that does not meet the business's functional requirements is considered inadequate. However, in practice, these requirements are not always directly provided to the designer. In some situations, they may be determined indirectly, considering other factors. Generally, it is up to the network designer to identify and document these functional requirements, ensuring they are approved before starting the network design process.

• Technical: The technical needs that the infrastructure must provide, such as security, availability, and integration.

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  Note: Technical requirements help network designers define the necessary technical specifications (such as features and protocols) and the software version that supports these specifications, and sometimes influence the choice of hardware platform based on their technical requirements.

• Application: Specific application demands, such as required bandwidth and levels of criticality.

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  Note: Generally provided by application teams. In some situations, it is necessary to survey this information with the main users of the environment to be developed/designed. A network that fails to meet expectations (quality of experience) also means that the designer failed to identify the business objectives, consequently causing the IT team to be seen as a cost center rather than a "business enabler."

  Mindset

  A designer's mindset is an essential factor. Knowing the technology is important, but success in network design heavily relies on a design-oriented mindset. Many professionals do not develop a design mindset until later stages in their careers. Unlike an implementation mindset, a design mindset requires a strategic and high-level approach to solving problems and creating solutions that meet business and IT operations needs.

  Design Use Cases

  Specific use cases help shape the design according to organizational needs. Some examples include:

  • Design for new environments (Greenfield).

  • Updates in existing environments (Brownfield).

  • Integration of new technologies or replacement of old technologies.

  • Mergers, splits, or scaling of existing networks.

The Role of Business

Network design must always align with business objectives. It is crucial to understand the business's priorities, drivers, and expected outcomes. This ensures that the designed network effectively supports current and future services and applications.

Constraints

Constraints limit design options and must be carefully analyzed. They may include:

• Financial: Limited budgets.

• Technical: Legacy infrastructure or incompatible technologies.

• Personnel: Lack of technical expertise in the team.

• Time: Tight deadlines for implementation.

Why

A critical question in any design process is understanding the "why" behind each decision made. Understanding the underlying reasons helps identify requirements that may not have been explicitly stated but are essential for the project's success. This ensures that the design is truly aligned with the actual needs of the business and daily operations. By exploring the "why," we can uncover hidden motivations and expectations that influence the design, allowing the final solution to not only meet current requirements but also be flexible enough to accommodate future demands and changes in the business environment. This proactive approach helps avoid rework and ensures that all aspects of the design are carefully considered, resulting in a robust and efficient infrastructure.

Design Scope

In any design project, it is essential for network designers to carefully analyze and evaluate the design scope before starting information gathering and planning. Therefore, it is crucial to determine whether the design task applies to a new network (greenfield) or an existing production network. Additionally, it is important to identify whether the design covers only one network module or multiple modules.

This prior definition of the design scope directly influences the type of information that needs to be collected, as well as the time required to create the design. For example, clearly identifying the scope helps designers determine which areas and functions need more attention and should be addressed in the project. As a result, information gathering will be more focused on these specific areas, optimizing the design process.

Design Use Cases

The network design process can vary depending on the scenario in which it will be applied. Below are the main use cases that guide the design approach, based on the specific needs of the environment:

Greenfield (New Environment)

This case occurs when the design is for a completely new network, without existing infrastructure. It is an opportunity to start from scratch, allowing greater freedom to choose technologies, architectures, and strategies that best meet the requirements. The focus is on creating a solution aligned with business needs, without the limitations of legacy systems.

Brownfield (Existing Environment)

In this scenario, the design is for an existing network. The goal might be to improve performance, integrate new features, or fix issues. It's necessary to consider the legacy infrastructure, ensuring compatibility and continuity during implementation. This requires balancing innovation with preserving what already works.

Add Technology or Application

This use case involves integrating new technologies or applications into an existing network. Examples include implementing an IP telephony solution, new security systems, or collaboration tools. The challenge is to ensure that the new technology integrates efficiently without compromising the performance or stability of the current network.

Replace Technology

Replacing technology occurs when existing components become obsolete or inefficient, and an upgrade is necessary. This can include swapping hardware, like routers and switches, or migrating to new software solutions. The focus is on modernizing the network, improving its capacity, and supporting future demands while minimizing disruptions.

In today's article, we explore in detail the main factors related to network design fundamentals. These fundamentals are extremely important because they form the foundation upon which the entire network will be built. It is essential that the designer, responsible for planning and designing the entire project, clearly understands these concepts. A deep understanding of these principles allows the designer to make informed decisions about the network architecture, ensuring it meets the current and future needs of the organization. Additionally, these fundamentals help identify potential challenges and plan effective solutions, ensuring the network is robust, efficient, and scalable.

In our next article, we will be discussing network design principles, covering topics such as security, scalability, availability, cost, and management.

I’m waiting for you there 😊