RAATS WIFI




Wi-Fi is a Passion

blogs

Overview - Wireless design



Wireless design is a part on itself, yes you can learn the theory behind how to design a wireless network; however, practice and experience enhance the skills of a good wireless designer.

Practice with wireless designs is to avoid bad designs. Some problems that can occur with bad designs are:

Insufficient coverage results in dead spots and low data rates. This means no connection or slow connections. You cannot just solve this with more access points.

Insufficient capacity results in that not all the clients can connect or do not accomplish their demands of the network. There is a limit to the number of clients that can connect to one access point.

With bad design, it is possible that there is no scalability for future growth. With designing a network, you need to take into account not just the requirements for tomorrow, but typically 6 months to a year ahead.

Designing a wireless network is not just focusing on the RF. There are still other functional requirements that need to be taken into consideration, for example guest access and onboarding.

Those four points are based on bad design, but there are also two other options, no design or Cookie Cutter designs. With no design, you need to guard that there will be no evolutionary implementation. This means that you implement access points over time, for example a couple this month, and some a couple months later. The issue with this is that the access points can interfere with each other in the bigger picture, but if you do not design the network in a bigger picture you are not aware of those issues.

Another no design example is based on Ethernet availability. This means that you deploy the access points where Ethernet cables are or where enough Ethernet ports are or based on the PoE ports. The access points are deployed on less ideal locations.

A Cookie Cutter design is one access point per classroom design. In other words, one design for multiple locations. This is not a good design since every location is unique. I am not saying that one access point per clasroom is bad, but there needs to be a good reason for doing this. A predictive or post site survey can have the results for one access point per classroom, but this is not true for all school buildings in the world. So, it is possible that there is a higher hardware cost with this design or poor performance because of too many access points, due to being over engineered.

Knowing what about bad design, no design or Cookie Cutter design, let’s look at good design. There are four steps to a good design: Define, Design, Implement and Validate. The SWEEP process (Standardized WLAN Enterprise Engineering Process) from the Wireless LAN Association talks about Define, Design, Deploy, and Validate. Those stages are each described in its own book.

Define: This is defining the project; the most important part is gathering the information that is needed, such as requirement analyze, information gathering and checklist (for example pre-site survey checklist). Beside the wireless knowledge that you need, you also need communication skills. It is important to translate the customer needs into requirements where you as designer can work with. A lack of asking questions is a lack of answers and that results in a design that maybe doesn’t fit the customer needs.

Design: During this phase, you will use the blueprints to create a design. You can do this with an AP on a Stick (or pre-site survey) or a predictive site survey with a planning tool like Ekahau or a combination of those which is called a hybrid site survey. You do the site survey for knowing the location of the access points. This is not only location placement, but also controller and AP settings and Quality of Service

Implement: This is about deploying the wireless network and configuring the infrastructure like DHCP, DNS, routing and the wireless infrastructure. How is the power and network access managed, by PoE or power injector? When those are in place the access points and the controller need to be configured.

Validate: Does the network meets all the requirements that are defined in the define stage? The chance is that you need to adjust the network and validate again and repeat those steps maybe a couple times. It can take up to two days when you are done and have a working network that meets all the requirements. You then validate the network on coverage, capacity and capabilities by a post site survey or throughput tests.

All those four stages are covered in-depth in other blogs. This blog is just an overview.