As I talked about in a previous blog, there is a bit of black magic – or call it fuzziness – to Wi-Fi technology. For example, do you know how fast your Wi-Fi connection is running right now? Unlike a wired Ethernet connection, you most likely don’t. Wi-Fi operates at literally hundreds of different speeds (data rates), all depending on dozens of variables. And the speed can change with every single data packet that gets transmitted!
In 19 years, Wi-Fi has made incredible strides to stabilize and perform at the high level we enjoy today. But the variability of Wi-Fi can make things confusing. And unfortunately, some in the industry try to use this confusion to their advantage. By controlling the variables in play, they will create outcomes that are favorable to their products, for example, when running tests comparing one product to another.
Given this background, let’s talk about something that has created some controversy in the industry – running all radios on an AP in the 5GHz band (or in 802.11ac mode). Xirrus pioneered this approach over 10 years ago with what we call software-defined (or software programmable) radios. Running all radios on 5GHz means that a Xirrus AP can operate entirely at the highest Wi-Fi speeds available, approaching speeds twice as fast as traditional non-programmable APs. For that reason, one Xirrus AP can replace two (or more) traditional APs – two for the price of one. When it comes to cost, this is a big deal.
How do we achieve this? Through our innovative approach to AP design. Traditional APs have a fixed configuration, with one radio on the slower 802.11n standard (2.4GHz band), and the second radio on high-speed 802.11ac (5GHz band). This design is intended to support both older and newer Wi-Fi clients at the same time. However, 80% or more of today’s Wi-Fi device population supports the newer, faster 5GHz technology, creating a highly suboptimal situation where 50% of your infrastructure is dedicated to supporting just 20% of your clients. To correct this imbalance, vendors will tell you to turn a lot of those 2.4GHz radios off, translating to wasted resources and money, and buy more APs to get more 5GHz radios, wasting even more money. In contrast, Xirrus allows all radios on an AP to operate at high-speed 802.11ac to optimize support for the faster 5GHz technology. No wasted radios, no wasted infrastructure.
In 2016, two other enterprise Wi-Fi vendors finally joined the club by introducing APs capable of dual 11ac / dual 5GHz operation. But despite the obvious trend toward dual 5GHz support, most Wi-Fi vendors continue to sit on the sidelines. Amazingly, they even try to dispute the efficacy of this functionality and raise doubts about its viability. These vendors, such as Aruba and Ruckus, run various tests and publish results to try and prove their case. That’s all the more amusing to us here at Xirrus, given our long history in pioneering the use of software-defined radios, and the fact that we have tens of thousands of successful installations around the world successfully operating the technology.
Well, at Xirrus we run tests as well. In 2014, we commissioned a test with Miercom to compare 802.11ac Wave 1 solutions from multiple competitors against Xirrus solutions, which came back with very compelling results.
With 802.11ac Wave 2 now in the Wi-Fi mainstream, we have some new results to share. We decided to run a new round of tests in response to the ongoing debate over dual 5GHz Wi-Fi, partly in light of a recent Aruba Networks blog questioning the viability of a dual 5GHz solution from Cisco. No one should be surprised that the company is trying to spread uncertainty and doubt about this capability, since this lack of functionality hurts their sales. Even less surprising is that Aruba was able to get test results to match their claims, all by controlling the variables of the test.
In contrast, we endeavored to take a more even-handed approach, using a simple test scenario we run regularly in our Quality Assurance group. We took an Aruba AP315, their latest Wave 2 four-stream AP, and tested it against a Xirrus XD2 four-stream model. We kept the test as simple as possible, with one high speed client connected per radio, specifically a MacBook Pro with 3×3 11ac Wi-Fi. From our testing observations, one client per radio generates the highest bandwidth, as opposed to multiple clients per radio. To generate traffic and measure results, we used the IxChariot test tool.
The first set of tests used a traditional AP configuration, with one radio in each AP operating in 2.4GHz at 802.11n speeds, and one operating at 5GHz using higher 802.11ac speeds. In the first test, both radios used 20MHz wide channels. In the second test, the 5GHz radio was changed to use 40MHz wide channels, which adds greater capacity to the radio. The 2.4GHz radio was left at 20MHz, as it is impractical to use wider channels in the 2.4GHz band in most any environment due to lack of available spectrum.
As the results show, the total throughput of the two APs was relatively close, with Xirrus 18% higher in the second case. As expected, the results in the second test were higher than the first, given that wider channels with greater capacity were used on the 5GHz radio in this test scenario.
In the second set of tests, all radios were set to run at 5GHz (802.11ac). In this case, only the Xirrus AP was configurable to run in dual 5GHz mode, as the Aruba AP only supports one 5GHz radio. So, an all-5GHz configuration for the Aruba AP was accomplished by turning off the 2.4GHz radio, a configuration recommended by Aruba in environments where mostly 5GHz radios are desired.
The results in this case demonstrate the limitation of fixed configuration APs such as Aruba’s. When designing for today’s clients, which are primarily 5GHz, you want to run most radios in 5GHz. To achieve this, Aruba will have you turn off all your 2.4GHz radios – 50% of the radios in your infrastructure! Xirrus, on the other hand, allows you to switch all your radios to 5GHz, enabling much greater Wi-Fi performance per AP.
So what can we conclude from these tests? Dual 5GHz / dual 11ac operation works! Simple as that. This is nothing new to Xirrus, as we’ve been advancing this approach for years, with thousands of satisfied customers. The takeaway is that you should beware of negative statements about this functionality when they come from vendors who do not support dual 5GHz operation. The lack of dual 5GHz support represents quite a major gap in their solutions, giving them an incentive to spread doubt about this feature.
Yet all the trends indicate that the traditional fixed configuration approach has become increasingly outdated. Even if you have a fair amount of 2.4GHz-only clients in your network today (e.g. a set of laptops you purchased several years ago), there is no doubt that the industry continues to move toward 5GHz as the preferred Wi-Fi operational band. Make sure your solution can adapt to these changes over the course of its lifespan to ensure a scalable, future-proof Wi-Fi network. With customizable Wi-Fi from Xirrus, you get two APs in one – letting you cut costs and prepare for the future, all in one solution.