802.11ax – better known as Wi-Fi 6, is the latest Wi-Fi specification standard capable of delivering greater performance and capacity, enhanced security, more range, and increased efficiencies unrivalled by the Wi-Fi generations that came before it. The latest standard is still yet to be ratified, but this hasn’t stopped vendors from releasing hardware that conforms to the specifications outlined in the draft state of the proposal.
If your Wi-Fi infrastructure is due for a refresh, you may have already had, or are currently in discussions with vendors and/or resellers about making the leap toward a Wi-Fi 6 capable network. While there are certainly pros and cons of implementing cutting edge technologies, the most important decision you will make while planning your Wi-Fi refresh is whether you decide to engage a specialist to help you design your new network.
The functions of a Wi-Fi network and the services it supports vary greatly between industries, but one thing is common across them all – a failing or poor performing Wi-Fi network due to a bad, or lack of design can be detrimental to the success of your business. It doesn’t matter what hardware vendor you choose, what the hardware’s advertised specifications are, or how much money you spend on hardware, the performance of your network is bound to the strict laws of physics and Radio Frequency science, and client device capabilities. A great understanding of this and designing accordingly is key to squeezing out every ounce of performance from your shiny new Wi-Fi 6 hardware.
Here are just a few industry-specific risks in running a poor performing Wi-Fi network:
Long before we get in to the nitty gritty technical details of network design, it is critical that we start by addressing the business requirements that are driving the network upgrade with key stakeholders. In fact, a good Wi-Fi engineer will start to gather information about your business long before they set foot onsite. This allows the engineer to be more prepared by already having an understanding of the products and services offered and who your customer is.
Business requirements are generally gathered in meetings, before potential hardware and software options have been discussed. Common examples of business requirements include:
Once we have determined business requirements, we must then determine how the wireless network will be used. Some examples include:
Location and voice services, for example, have a completely different set of requirements over data services. BYOD and untrusted guest devices will require different levels of security and access than managed corporate devices.
We then need to understand what applications will be used on the wireless network and what their minimum requirements are. While the delivery of some application data can handle network delay or retransmissions, others require the network to support a baseline level of performance for them to operate efficiently. Some critical metrics include:
What is the maximum number of users expected to access each area at any given time? This, along with the application requirements, will determine the density of APs to be installed in each area.
We also need to determine the client device types that the Wi-Fi network will support. Every device and its supported capabilities and protocols will vary greatly between devices models, operating systems versions, chipset models and firmware versions. Knowing the limitations and capabilities of your client devices allows us to design a network that plays nicely with the devices, and it also sets expectations around what is realistic in terms of performance. Some of the key client capabilities affecting design decisions include:
Are we upgrading the wired network or are we to make use of the existing wired infrastructure? The wired network must be capable of supporting the requirements and demands of the Wi-Fi network. Some things to consider are:
Once the information gathering process is complete, it is then time to start piecing it all together and make decisions on the design.
There are many different architectural models in the world of Wi-Fi and each has their advantages and disadvantages. Some solutions provide a great level of convenience and ease of management, but might fall short when it comes to scaling beyond the current project scope. Other solutions will allow you to grow indefinitely, but may require a full-time wireless engineer to support it.
This is where we determine the appropriate AP models and antenna selection (if using models with external antenna options). If there are high density requirements in some locations it may be best to add additional APs with directional antennas to shape and focus the RF energy in particular directions. This allows for smaller high capacity cells, while also minimising interference caused by introducing more Aps.
AP transmit power is directly proportional to the range of a transmitted signal. Theoretical data rates are directly proportional to the clients achieved signal-to-Noise (SNR) ratio. SNR is the difference between the measured signal and the measured background noise.
So, why would we not just turn up our APs to maximum transmit power and receive the highest possible data rate? Well, consider an access point transmitting at is maximum power setting. It’s like two people having a conversation across a field where only one person has a megaphone. While the client can hear the AP at long distances, the AP can’t necessarily hear the client so the client repeats itself until the message is heard. The client may be able to download data, however it may struggle to upload data.
This is why it is necessary to match your transmit power to that of the lowest performing device in the network. The result is less retries, less interference from devices operating in the same frequency, and less chance of ‘sticky’ clients unwilling to roam between APs.
Every AP will transmit its signal on a particular channel per radio. In the 2.4GHz band we only have three non-overlapping channels. At the time of writing, there are 22 channels available for use in the 5GHz band in Australia. For the most part, the channels you choose to enable on your AP radios is largely determined by client support. The more channels we can enable and allocate to APs, the less likely two APs within the vicinity of one another will need to transmit on the same channel, reducing co-channel interference. An AP transmitting on a channel that a client does not support will introduce coverage holes for that client.
We may also decide to completely disable the 2.4GHz band or disable 2.4GHz radios on a subset of APs to allow for a much cleaner signals between the AP and client.
Now this is where it starts to get fun – determining where APs should be mounted, their orientation and specific radio configuration by way of site surveys. Decisions made during the site survey process using all of the detail gathered in the previous phases. There are three types of site surveys that can be performed during the design phase and which surveys should be performed depends on a number of factors. The types of surveys used in the design phase are:
While this is just a taste of the Wi-Fi design process, hopefully I have convinced you the importance of budgeting for a design on your next Wi-Fi upgrade. When you’re ready reach out to the experts at Data#3 to assist you in making the transition to Wi-Fi 6. With a Cisco Gold Partner and an Aruba, a Hewlett Packard Enterprise, Platinum Partner you can be sure you are choosing the right people for the job.
Tags: Mobility, Cisco, Networking, Wireless Network, Professional Services, Wireless Infrastructure, Aruba, HPE Aruba, Project Services, Network Infrastructure, Wireless, Wi-Fi, Assessment & Design, Network Modernisation