Thanks to consumer-focused WiFi systems from the likes of Google, Eero, Ubiquity, and Linksys, wireless mesh networking is getting a lot of attention. The idea behind mesh WiFi is that a single WiFi access point is hard-wired into the LAN. This WiFi gateway then connects other non-wired WiFi repeaters that are deployed throughout an area. Since the wireless signal is dispersed among the various nodes, a mesh network can provide better wireless coverage to areas that would be prone to dead spots compared to a centralized WiFi deployment in which nodes only communicate with a single access point.
While a wireless mesh network may work in the home, enterprises have generally avoided mesh WiFi. However, wireless advances have overcome some of the performance issues associated with the technology, expanding its applicability in the enterprise.
Despite the newfound popularity in the consumer WiFi world, mesh WiFi is nothing new; in fact, mesh technology has been around for decades in the enterprise. Most enterprise-class wireless access points can be deployed either in the traditional hard-wired manner or in a mesh configuration. The most common use cases for enterprise wireless mesh networks have been outdoors to provide WiFi in parks, beaches, and between buildings that had no physical cabling connecting them. But other than that, organizations have mostly avoided WiFi mesh deployments because they tended to be slow and unstable.
Common problems included the fact that from one hop to the next in a mesh WiFi configuration, you lose over half the speed since wireless communication is a half-duplex architecture. Thus, if you are running a legacy mesh WiFi network using 802.11g speeds at 54 Mbps, connectivity is going to be incredibly slow. For example, if end devices are required to pass through three mesh repeaters in order to reach the wired portion of the network, your absolute best throughput is going to be around 2 to 5 Mbps. This might be sufficient bandwidth for one or two end users and light network usage, but any more and you’re going to run into severe bandwidth constraints.
However, since today’s 802.11ac Wave 1 and 2 access points with multiple streams can achieve wireless throughput between 400 Mbps and 1 Gbps, mesh deployments today are far less plagued by bandwidth loss from one repeater to the next. This makes a mesh deployment in the enterprise viable as long as the number of repeater hops is strictly limited to a maximum of three.
Another major issue that dogged wireless mesh deployments is that wireless interference could be far more pronounced. In the old days, enterprise APs only had a single wireless radio. That meant that the AP had to juggle the servicing of end devices with passing data to and from its meshed peer along the path to the gateway. This not only creates throughput inefficiencies, but using the same frequencies causes interference. Additionally, because the mesh often covers far more area than a typical WiFi cell would, the opportunity for interference can be much greater. To help reduce these problems, modern APs now often come installed with multiple, independent radios. That way, one radio can be designated for end devices while the other is used for the mesh backhaul.
Here’s the bottom line on mesh WiFi in the enterprise: You can consider it a viable option in a wider range of deployment scenarios than ever before. When Ethernet cabling isn’t available, too expensive or otherwise impossible to pull, mesh WiFi is a distinct possibility. In addition to outdoor areas, mesh deployments are a good fit for historic buildings where pulling new cable is prohibited. Also, consider a mesh network for rented spaces or temporary locations.
If you plan to design and deploy a wireless mesh network, there are a few things to keep in mind. First, make sure you have power where you plan to deploy your mesh repeaters. Since you won’t have an Ethernet cable, you obviously won’t have Power over Ethernet (PoE) as an option. Also, as stated previously, try to keep the number of repeater hops back to the gateway to an absolute minimum. Finally, make sure that your WiFi spectrum is free of major interference. Modern mesh WiFi can be configured in a multi-path design, which helps eliminate single points of failure and avoids some wireless interference issues.