The basics of network design and six top certs to help you master them
Posted on
September 30, 2016
A network engineer must master the principles of design in order to succeed.

While driving your automobile, have you ever wondered what it took to make it operational? To produce an automobile, the manufacturer began with a very early stage in this process β€” design. According to the design specifications, the manufacturer compiled different components and features to produce the vehicle. Once completed, the car is ready to run over the road, but it will still require regular maintenance to ensure it operates as per the design process.

This is all fine for automobiles, but what does this have to do with PC networking? The same logic applies because the same processes and principles utilized to produce a functioning car also apply to building a computer network. Every high-performance network infrastructure begins with a thorough design, defined as an iterative process for building a network that meets customer needs.

Network designers start by collecting client requirements such as the number of servers, bandwidth, latency and many other operational specifications and then translate them into an architecture to meet the requirements. The customer may be external (another company) or internal β€” designing a network to host teams or departments in your same company.

The initial output of the network design process is a low-level design (LLD) document detailing all network elements including topology, device models and configuration, logical addressing details, network protocols, redundancy and high-availability descriptions. This document is important because it's used to select and purchase appropriate network devices and to build the infrastructure.

Network designer skills

Excelling in design is a passion for many network engineers β€” an interesting integration of different components to create an infrastructure that matches customer needs. Successful network designers will possess four traits:

A thorough understanding of how networks operate β€” Good network designers have an in-depth understanding of network protocols and device operations. This allows them to anticipate how their design will run during operation. Knowing how the network will operate is important, not only for implementation, but also for potential future upgrades.

Exposure to different vendors β€” Talented network designers have a knowledge of and professional relationships with various vendors. They are able to work closely with vendors to meet their design needs.

Knowledge of network device capabilities β€” It is crucial for a designer to understand the capabilities of the various network devices including device throughput, capacity and performance metrics. This enables a designer to select and purchase the equipment that best matches their design parameters in a cost effective manner.

Experience β€” Like any other career, the more experience you have the more effective your work output. Nothing will shape a network designer's skills better than actually building designs and learning from previous ones β€” this includes what worked, and as just as important, what didn't work.

One of the best ways to master the ABCs of network design is to earn an official certification from a reputable organization. There are six network design certifications that are well-respected across the industry:

Cisco Certified Design Associate (CCDA)

An excellent and very popular design certificate, CCDA, although vendor specific, includes much that can be applied to any modern network infrastructure using a wide variety of equipment from various vendors. CCDA provides both a description for technologies as well as protocols used in design and best practices for creating high-performance and reliable networks.

CCDA is a beginning level certification for designers who are new to the field and looking to pick up fundamental design skills. By focusing on the design concepts of modularity and hierarchy, CCDA takes into consideration modern datacenter design as a way to accommodate other solutions like storage, systems and content networking, which use overlay techniques to run over standard network components. Achieving a CCDA certificate is a good starting point for a network design career.

Cisco Certified Design Professional (CCDP)

CCDP is a professional level certification that builds on the foundational-knowledge of the CCDA to do a deeper-dive into the concepts and technologies of network design. CCDP credentialed individuals have a recognized proficiency in designing and deploying scalable networks and multilayer-switched networks.

In order to sit for the CCDP exam, candidates must have CCDA and the CCNA Routing and Switching certifications, or any other CCIE certification. CCDAs are often working as senior network design engineers and senior analysts.

Juniper Networks Certified Design Associate (JNCDA)

Juniper focuses on promoting its career certificate holders into network engineers. Some people think Juniper is imitating Cisco's success, which is reflected in greater adoption of Cisco's products into the workplace. Whatever Juniper's motive, it's that their strategy is to attract greater numbers of network professionals to Juniper certifications.

JNCDA is a very popular network design credential designed to give practitioners a basic level knowledge of design theories and best practices. Earning a JNCDA requires candidates to possess a basic knowledge of routing and switching protocols, other Juniper network products, network security principles and hypervisors and load balancers. Although a beginner level certificate, JNCDA is rich in content dealing with modern network infrastructure design.

Juniper Networks Certified Design Specialist, Data Center (JNCDS-DC)

Juniper has developed a number of widely used products focusing on virtualized datacenter architecture that are high-capacity, low-latency and secure. With more Juniper datacenter products on the market, it was a natural step for the company to create JNCDS-DC.

This certification is recommended for network designers whose work involves creating network solutions for datacenters as well as interconnecting different datacenters. JNCDS-DC is designed for networking professionals and designers who already have a foundational knowledge of network design, theory, and best practices. JNCDS-DCs have the skills and abilities to addresses security concerns of modern virtualized networks using Juniper security products while following industry standard approaches. If you're a network designer utilizing Juniper products to build datacenters, the JNCDS-DC is an attractive and useful certificate.

Cisco Certified Network Professional (CCNP)

A network engineer must master the principles of design in order to succeed.

Rather than design focused, CCNP is an operational certificate, and an excellent choice for designers. The CCNP shares most of the contents (ROUTE and SWITCH exams) with the CCDP certificate. This matches with the previously mentioned importance of having deep understanding of network technologies and protocols. CCNP is rich in knowledge of layer 2 and layer 3 technologies, infrastructure security, VPN and network services as well as how to troubleshoot them. Pursuing a CCNP is a solid step to take especially if one plans on going deeply in design realm.

VMware Certified Advanced Professional 6 β€” Data Center Virtualization Design

As virtualization is more widely adopted in datacenter infrastructure, the gap in responsibilities between network and systems engineers is shrinking. Network engineers must have an understanding of system virtualization concepts in order to design infrastructures that support such systems.

This merging of responsibilities for network and systems engineers is happening in enterprises of all sizes. All of this makes VMware Certified Advanced Professional 6 β€” Data Center Virtualization Design certificate increasingly attractive for network engineers. Certified individuals are skilled in the logical and physical design of the VMware vShpere system starting from business requirements to vShpere configuration of physical components. The certificate gets its importance from the increasing use of VMware products in large datacenters, making it an excellent choice for network designers.

About the Author

Ahmed Badr is a network consultant with 10-plus years of experience designing, implementing and operating large scale network infrastructures. He holds a BSc in Communications and one in Electronics Engineering, and a Master of Business Administration. He also holds a CCIE certificate in Routing and Switching since 2008. Ahmed can be contacted at:

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