Getting Wired for Wireless: Performance

As we emphasized in our introductory blog about Switches and Robust Wi-Fi Deployments, an up-to-date switching underlay is a prerequisite for high-performance wireless access points (APs). Put simply, wired infrastructure needs to provide adequate speed for connections to the switch: from the access points, uplinks to aggregation and core switches, and to the cloud (or data center). This is because performance is only as fast as the weakest link. While fast access points are important, the full value of APs simply can’t be realized without an adequate underlying network. In an ideal network, all components – including the internet pipe – are well-matched to handle network traffic. A bottleneck at any point in the connection between a user and the cloud (or data center), will slow application performance and negatively affect the user experience.

Let’s take a closer look at the data flow. Beginning with user devices, the first step for wired networks is the connection from access points to switches. Over the past 5-10 years, most enterprise-class switches had 1-gigabit access ports to support access points up to and including Wi-Fi 4 (802.11n). The total throughput possible for a Wi-Fi 4 access point is below one gigabit per second, so connecting a switch to the 1-gigabit port was adequate. Anything faster wouldn’t make any difference to performance, as the AP remained the limiting factor to performance.

Wi-Fi 5 (802.11ac) Performance

Wi-Fi 5 (802.11ac) APs offer potential speeds of more than a gigabit per second throughput. According to a recent Dell’Oro report (August 2018), almost all enterprise APs sold as of 2017 were Wi-Fi 5 models. This means a 1-gigabit access port is on the cusp of becoming the bottleneck for top performance. Indeed, the more recent Wi-Fi 5 Wave 2 APs are capable of up achieving to 2.3 gigabits per second, though the practical limit is a little bit less. Ruckus lab tests confirmed Wi-Fi 5 Wave 2 throughput of one and a half gigabits per second, so a 2.5-gigabit port was sufficient to prevent the access port from being a bottleneck, at least for Wi-Fi 5 APs.

Wi-Fi 6 (802.11ax) Performance

However, next-generation Wi-Fi 6 APs (802.11ax) have already begun shipping, with IDC forecasting Wi-Fi 6 (802.11ax) deployment ramping significantly in 2019 and becoming the dominant enterprise Wi-Fi standard by 2021. This is because many organizations still find themselves limited by the previous Wi-Fi 5 (802.11ac) standard, especially in high-density venues such as stadiums, convention centers, transportation hubs, and auditoriums.

Wi-Fi 6 (802.11ax) access points (APs) deployed in dense device environments such as those mentioned above support higher service-level agreements (SLAs) to more concurrently connected users and devices – with more diverse usage profiles. This is made possible by a range of technologies that optimize spectral efficiency, increase throughput and reduce power consumption. These include 1024- Quadrature Amplitude Modulation (QAM), Target Wake Time (TWT), Orthogonal Frequency-Division Multiple Access (OFDMA), BSS Coloring and MU-MIMO. With the new Wi-Fi 6 (802.11ax) standard offering up to a four-fold capacity increase over its Wi-Fi 5 (802.11ac) predecessor, it is important to proactively eliminate potential bottlenecks at the switch by considering multi-gigabit.

Multi-Gigabit Switches for Wi-Fi 6

It should be emphasized that the transition to multi-gigabit switches to accommodate Wi-Fi 6 APs does not necessarily require a wholesale infrastructure upgrade. It can happen gradually by adding a few switches as needed.  Furthermore, most multi-gigabit switches today include a mix of multi-gigabit and gigabit ports. Only those ports connected to 802.11ax (Wi-Fi 6) APs require multi-gigabit speeds, while the other gigabit ports are adequate for computers, printers, VoIP phones, cameras, and additional Ethernet devices.

Conclusion

To take full advantage of the speed performance offered by 802.11ax (Wi-Fi 6) APs (up to 5 gigabits per second), our customers have already begun installing multi-gigabit switches to either replace or supplement older infrastructure. This is because system administrators cannot ensure a quality user experience by simply upgrading one part (access points) of a network. Reaping the benefits of 802.11ax (Wi-Fi 6) requires upgrades on the switch side as well. From our perspective, the transition to multi-gigabit switches should start now. With the average life for a switch being 5-7 years (and up to 10 years for many educational institutions), the need for multi-gigabit connections will almost certainly be upon us within this timeframe.

 

Rick Freedman
Rick Freedman

Director, ICX Product Marketing

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