"Network design professional" is one of the more prestigious job titles in IT. The network design process is an obvious and essential prerequisite for running an infrastructure that can meet the requirements of its users. In this article, we will go through the definition of network design, the design process - including different design tasks - and how to get started and achieve career advancement.

Network designers

Network Designers (designers) fit different network infrastructure components and technologies together to form a network able to satisfy the needs of their client. The outcome is a network topology (physical arrangement of the various network elements, including links, nodes, and so forth) and detailed specifications of different components. This includes a network diagram, protocols, cabling infrastructure, IP addressing scheme, and many more details.

The designer creates documents ranging from High Level Design (HLD) to Low Level Design (LLD) according to the level of details included. HLD documents include descriptions of the infrastructure and its components, and serve as a summary of what the final design will look like. LLD documents generally include much more detail. They typically contain full infrastructure details including description of technologies and devices used, down to the level of specific link speeds and cable types and lengths. The LLD is used during the implementation of the design and serves as a reference during different implementation phases. It is also a consulting document used after the successful implementation of the network.

The skill of a network designer lies in choosing the optimum and balanced mix of technologies and components that efficiently fulfill customer requirements.

Network design challenges

When designing a network, the designer must pay attention to a lot of details attached to the proper operation of the network. The process usually starts by collecting the requirements, or in other words, the expectations for the network. Network capacity in terms of bandwidth available for applications traffic as well as the number of connectivity ports on network devices are some of the important details that a designer needs to know in order to size different network components.

For example, the number of servers to be connected to the network reflects on the number of purchased switches. The available bandwidth is also referred to as network throughput, and is derived from the throughput of the different devices in the network.

Availability is another key requirement for network infrastructure. While less important applications require less available network, mission critical applications may require network availability up to 99.999 percent. Network availability is reflected in the design cost as it requires creating redundant (duplicate) devices to act as Active/Standby or even Active/Active devices.

Network reliability is important because it ensures that network devices can perform as claimed. If not, it's like buying a car with top speed of 186 KPH, but when you start driving the car, it breaks down before reaching that speed. A final important factor in network design is network scalability. Network infrastructure should be built with the availability of expansion to accommodate new services. It's always cost effective and faster to expand an existing network rather than build a new one.

Designing a network is a comprehensive process and each of the above mentioned factors should be carefully and completely addressed to design and build an effective and efficient network infrastructure.

Getting started in the field

There are two schools of thought to answering this question:

One mandates that network designers should have experience working in network operations. The argument is, "If you know how every component of a network operates, you can design a network." For example, if the professional had experience with the problems of specific network protocol he then can substitute it with another one during the design. The professional can then use practical knowledge rather than depending on theoretical concepts. This method can equip a professional with extensive hands-on experience and enrich his networking knowledge.

The second school of thought holds that, like any IT field, networking can be learned and developed. If you have enough knowledge of the concept or at least can understand it, experience can be substituted by book learning and consulting with more experienced professionals.

More likely the manner of becoming a successful designer is a combination of both schools of thought. Regardless of which method you choose to follow, I promise you that it requires a lot of knowledge, especially specific product knowledge and lots of practice.

Helpful materials and certifications

IT Network forum and Newsletter websites should be in the daily routine of a network design professional too. Besides being current on new articles and industry developments, there are a number of comprehensive certification programs from well-known vendors. Examples include Cisco's CCDA/CCDP/CCDE and Juniper's JNCDA/JNCDS/JNCDP (to be announced soon) network design certification tracks. Another good option is a CNET certification like CNIDP.

It is worth mentioning that when it comes to design, professionals should go for vendor neutral certificates. The gained knowledge and exposure to different vendors and products gives the designer flexibility in fitting different components in the design.

Being a successful network designer

It is crucial that network designers be up-to-date on the latest technologies and product portfolios of different equipment vendors. Successful designers rarely rely on one vendor. It is more common to use a mix of vendors when building a network infrastructure. This is especially true for security devices. The professional should know the capabilities of different devices so as to correctly position them within the solution. Using open standard protocols, network devices can be fit together in an orchestrated topology that provides smooth operation.

While it seems tough to follow the rapid innovations in technology, it's an interesting routine to know new concepts and apply them in designs. Vendor workshops, webinars and conferences are good events to assist in grabbing good knowledge and tips about technologies and products. Social networking with other professionals also provides knowledge that can add to your professional skills. The more exposure to technologies you get, the more capabilities you have in this field.