In the market for… Wi-Fi
Written by: Sam Fenwick | Published:

Wi-Fi may be all around us, but there is a huge amount to consider when deploying it for
business use, as Sam Fenwick discovers

As telent’s CTO Paul Dobbins says, “the challenge of Wi-Fi is that everybody thinks they can do it because you just deploy a few access points and you’ve got it, we’ve all done it at home. That’s true, but the service you get out of it is directly proportional to the quality of the network’s design and the product that you’ve procured.”

Dobbins adds that cloud-managed Wi-Fi is “becoming popular” and highlights its ease of deployment. He says it is well suited to “a retail operation where you don’t really have much of a technical department”.

Chetan Hebbalae, senior director of product management at Cambium Networks, says: “A cloud-first network eliminates the need for a hardware controller, offering global economies of scale, and significantly reducing the cost and time to market, making it very easy to get network equipment up and running. Gone are the requirements to host a cumbersome rack-based controller with its associated space and power requirements. The cloud delivers scale and redundancy, making the control and management function highly available. In our cloud-based system, the Wi-Fi APs are semi-autonomous, making local decisions as in the case of Wi-Fi mobility, aka ‘roaming’, so control communication latencies are reduced and the network is robust enough to run even if the cloud were unavailable. Another factor is the ability to ‘rent’ the controller. The cloud design makes it naturally possible to move to a subscription model, so Wi-Fi customers can save on capital costs in terms of controller purchases.”

Turning to hardware procurement, Dobbins warns that “if you were to go to the cheap end of the market, the total cost of ownership could be far higher than you’d expect because [you might find that] making upgrades and changes is far more laborious and difficult [than would otherwise be the case]”.

Josh Blakey, head of pre-sales at LAN3 (a network specialist), adds: “There are a lot of cowboys out there, [so] engage with a couple of different partners, do your due diligence in terms of technology, and ask for proof of concepts.” He adds that providing a client with a single access point to test doesn’t show the full value of the product and how it handles things such as roaming. In addition, “don’t rush into these decisions, you’ve got to plan it properly and think about what it is you’re trying to achieve before you start looking and testing, because if you don’t know what you’re going to use the product for in one, three, five years’ time, how is that going to translate into a successful solution?”

Dobbins says: “Where a free choice is allowed, go with [vendors] that you’ve built a strong relationship with; you’ve gone through the training, you understand the product, you understand how to deploy it properly, have far better insight into their product lifecycle, what they’re planning next, and what their latest change in technology is going to
be – that’s what we would always do.”

One dilemma facing anyone seeking to procure a new Wi-Fi system or replace an existing one at the moment is whether or not they should opt for Wi-Fi 6 (802.11ax), or older (but still relatively new to the market) Wi-Fi 5 (802.11ac) technology. Should they be holding out for Wi-Fi 6?

“It depends on a user’s timeline and budget,” says Hebbalae. “802.11ax has not yet been ratified by the standards bodies. That is expected only sometime in Q3 2019. So, any devices purchased prior to that run the risk of not being standards-compliant. Further, to realise the benefit of the 802.11ax standard, the client devices must support it too. Historically client devices have supported such advancements after the standards.”

Craig Kirby, technical pre-sales engineer at D-Link Europe, adds that in the past when 802.11n first arrived, a lot of devices came out that were unratified and firmware updates usually fixed any issues, but sometimes the work of the IEEE on the Wi-Fi standards prior to their ratification can lead to changes that need to be made in hardware.

Hebbalae says it “is important to note that 802.11ax is backwards-compatible, so we expect any 802.11ac-based networks to continue to work well into 2020 and beyond.

“So, it is best to delay any migration to 802.11ax until the standards are ratified. 802.11ax-capable client devices probably won’t start to be available until 2020, so that leaves time for the infrastructure to be ready before the client devices show up.”

Kirby adds that those seeking to carry out large installations “might be more confident in going for something like 802.11ac Wave 2, a technology that is in place now and still uses multi-user MIMO. That will allow you to get better streaming speeds from devices in the current area, and you’re still able to get 1Gbps speeds with Wave 2 access points even in a bad area.”

Don’t forget backhaul
LAN3’s Blakey says people often forget about backhaul as “wireless for a lot of people is a lot more of an exciting conversation topic than switching. You could put in a brilliant wireless solution that gives you loads of throughput and great features, but if you’re sat on a 100Mbps LAN with daisy-chained interconnections, with a poorly designed VLAN and IP schema, then it’s not going to work, and it’s very easy to then blame the wireless solution or the partner or the vendor without taking a look at what the real issues are.”

Hebbalae adds: “Popular backhaul options include Gigabit Ethernet lines that often connect ultimately to a fibre tap point or wireless backhaul or mesh networks for outdoor Wi-Fi systems. In case of wireless backhaul, having a good network plan, proper channel selection and frequency reuse can significantly improve the throughput. Backing that with a wireless backhaul system that can offer deterministic time-based access (TDD) over unlicensed backhaul using GPS sync often results in a system that can deliver on business SLAs.”

Blakey also notes that a desire to use a Wi-Fi network for Voice over IP (VoIP) calls has significant implications for its design. To ensure a good VoIP service, segregation of traffic, ensuring sufficient bandwidth and quality of service, all have a role to play. Customers need to be aware of the financial impact, as satisfying this requirement may require additional access points (particularly in corridors). He adds that some vendors have their own fast handover solutions to enable someone on a call that is running over the Wi-Fi network to seamlessly roam from one access point to another without experiencing any issues – “they all do it in their own way”.

Blakey adds that wireless surveys tend to be very undervalued and he considers them to be “absolutely integral to any deployment”, though he states that for small deployments of fewer than 10 access points, a predictive survey may suffice as long as any environmental challenges are understood.

Hebbalae notes that Wi-Fi’s popularity and use of unlicensed spectrum mean that “both topology challenges such as presence of walls (indoor), foliage (outdoor) and radio signal challenges such as the presence of interference are very common. Good Wi-Fi vendors implement smart radio management features such as automatic or dynamic channel selection, and automatic transmit power control combined with device-handling features such as air time fairness and band steering to mitigate the effects and steer client devices in a way that can deliver high-speed Wi-Fi to end-users.”

Being able to control transmit power is particularly useful in areas where there is metal sheeting, which D-Link’s Kirby says in some cases can create ‘phantom signals’ that end up being received at the wrong time – in such cases, the best remedy is to reduce the transmit power. He adds that in these environments, access points capable of operating in both 2.4GHz and 5GHz, support multi-user MIMO (through compliance with the 802.11ac Wave 2 standard) and have external antennas may be preferable. He adds that automatic transmit power control also allows a Wi-Fi network to be more resilient, as it can be designed to use access points running at low power to cover all the required areas, and then if one of them drops at any point, nearby access points can increase their transmit power to cover the affected area.

The great outdoors
Turning to outdoor deployments, Cambium Networks’ Hebbalae describes these as being particularly tough as “the conditions for outside interference can’t always be foreseen” and “indoor enterprise or campus deployments are easier to control physically as they are often under a single administrative entity. Furthermore, indoor obstacles like walls can actually be a boon when planning, as they enable natural frequency reuse for high-capacity deployments.”

D-Link’s Kirby also says part of the issue is that in some outdoor locations, such as a field, there are fewer buildings or roads to bounce the signal, which tends to reduce the effective range, and the greater difficulty in propagating the signal means external antennas with a high dBi rating may be more suitable than internal ones. He adds that you also have to consider vandal-proofing outdoor devices.

Hebbalae says “large-scale outdoor networks not only need to handle the traditional challenges of design and coverage but need to build in resiliency as well. Adverse factors include physical and radio interference, as well as handling the elements. New sources of physical interference such as foliage from trees or advertisement billboards can create unanticipated issues.”

He adds that “sources of radio interference may crop up not only from other nearby unlicensed wireless equipment, but in some cases from nearby LTE devices as well, such as in those operating adjacent to the 2.4GHz unlicensed band.

“In outdoor locations, the ability to pull the backhaul is not always as neat as the indoor use-cases. Getting fibre to where you want the access point to be deployed is often an expensive proposition, not to mention rights of way and sources of power. Fortunately, technology has advanced to the point where resilient circuitry design, optimised antenna designs and IP67 [hardware] have resulted in proven outdoor solutions [that allow us to] deploy tens of thousands of outdoor access points and manage them economically from a cloud-managed system.”

A matter of security
Telent’s Dobbins warns that Wi-Fi spoofing is becoming more common, but there are new features and products that can address this. “They certainly allow you to at least monitor for where people are trying to spoof Wi-Fi services to ensure that your customer base isn’t being affected.”

“For wireless and networking edge protection you would be looking at a network access control (NAC) solution,” says LAN3’s Blakey. “They’ve been around for a long time but have traditionally been very expensive and needed somebody to manage them full-time. However, vendors are coming up with much more streamlined solutions. For example, Aerohive’s new A3 NAC product very much delivers on that security piece but doesn’t require a huge amount of management after the initial set-up; it’s very easy to maintain. It’s the same with Ruckus’s Cloudpath and other vendors such as Cisco and HPE.”


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