Tuesday, January 8, 2019

Wi-Fi Mesh: What to know about enterprise mesh networks

Wireless mesh has been around since the early times of Wi-Fi but is getting more attention lately in the consumer world. There are mesh systems out from Google, Eero, Linksys, Netgear, and pretty much every networking brand that targets homes and small offices. But there are Wi-Fi mesh solutions for the enterprise market as well.

The idea behind Wi-Fi mesh networks is that not all the access points (AP) have to plug into the wired infrastructure. Those that aren’t plugged in get their network connection wirelessly from a nearby mesh AP. For smaller mesh networks, you might only have to have one mesh AP plugged into the wired network. In larger networks, you would need multiple mesh APs plugged into the network to support those that are wirelessly connected.

Wi-Fi mesh differs from WDS

Don’t confuse the wireless distribution system (WDS) feature supported by most routers and APs with Wi-Fi mesh. Although both can extend a Wi-Fi network without running ethernet to the APs, there are some crucial differences between the two technologies. Mesh is basically a smarter and better version of WDS that’s easier to setup.

WDS typically only allows you to configure APs to wirelessly connect to another AP that has a wired network connection. The wireless connections to the host APs are generally static and require manual configuration of MAC addresses. Additionally, there are limits and complications with the amount of wireless links between APs and the security/encryption of the wireless. Furthermore, WDS links usually utilize the same radio and channel as regular Wi-Fi traffic, which isn’t good for Wi-Fi performance.

Mesh APs can wirelessly connect to mesh APs that have either a wired or wireless connection to the network. Many mesh APs have a radio dedicated for the wireless links between the mesh APs. That way the regular dual-band radio(s) can just serve the Wi-Fi users.

The wireless links between APs are designed to be automated and offer self-healing multi-path links or hops. This helps make setup easier and gives better redundancy in the wireless links. So, if one mesh AP fails or the environment changes and negatively affects a wireless link, the wirelessly connected mesh APs are designed to find another mesh AP or better path to a host AP.

When Wi-Fi mesh is a better fit than traditional APs

Even in the enterprise, you may want to consider deploying mesh rather traditional APs in certain cases. Mesh installs can be faster and less expensive in environments where there aren’t any existing cables.

Even if pulling cable isn’t a big issue, you still might consider mesh for networks where you think there will be drastic building or environmental changes in the future. The same applies if there will be significant changes in the desired coverage area or levels. Mesh allows you more easily patch any coverage or capacity holes, or move those coverages or capacities easier.

Mesh is especially useful when it’s hard or impossible to pull cables. This could be the case with old or historic buildings, parks, and outdoor venues. Even if pulling cables isn’t a big issue, you might consider mesh for smaller buildings or networks as well to save some money, especially if throughput isn’t crucial.

Mesh networks are ideal for temporary indoor or outdoor networks, such as for events and conferences at public venues. It’s also great for rented spaces, such as an office where there isn’t viable cabling and you don’t want to invest in a property you don’t own.

Wi-Fi mesh deployment challenges

Throughput is one of the most important factors to consider before going with a mesh Wi-Fi network. If you must have the highest throughput and fastest Wi-Fi speeds, then you may just want to go with traditional APs. This is because with every wireless link between the mesh APs, the throughput drops about 50% from what it is at the prior AP.

The throughput issue with mesh APs could be acceptable, especially with today’s data rates offered by 802.11ac. The throughput drop may not be an issue or noticeable if users will be doing general web/network browsing. But it could certainly be noticeable if a lot of users will be trying to utilize high-bandwidth applications, like HD video streams or photo uploading.

Utilizing mesh also introduces more variables when it comes to Wi-Fi survey and design. Enterprises need to be extra careful in the placement of the mesh APs, considering the amount, length, and signal quality of the wireless links between the mesh APs. Generally, you don’t want any more than 3 hops back to a host AP that has a wired connection to the network. When designing, you also still have to consider the power source for the AP, so that could limit your placements.

Keep in mind that you usually will need more mesh APs to cover a given area than you would if using traditional APs. This is because you must place mesh APs closer together so they can effectively communicate between each other. So there are cost savings of not running some cables, but that maybe eaten up by higher number of APs you must purchase.

Despite the longstanding 802.11s standard from the IEEE and more recent Wi-Fi EasyMesh standard from the Wi-Fi Alliance, most mesh APs aren’t compatible between the different vendors. So, always stick with one brand and perhaps the same model just to be safe. Consider keeping a few extra mesh APs on hand for replacements or if there are network changes, just in case you can’t purchase that model in the future.

Checking out mesh APs

Many enterprise-level APs actually have a mesh functionality built-in, even though most IT pros typically only utilize the traditional AP deployment mode. So, perhaps check out any mesh functionality of the existing APs you have installed or are used to. But with that in mind, APs that are marketed as mesh APs will usually have better mesh features. Mesh features of some APs maybe more like WDS functionality. The exact features, limitations and performance can vary greatly between the AP vendors.

Ubiquiti Networks offers a mesh line with the UAP-AC-M and UAP-AC-M-PRO, but there isn’t a third radio dedicated for the mesh links. They call their mesh functionality Wireless Uplink, and it is actually supported by most of their modern traditional APs. Even their legacy APs support it, but is limited to one wireless hop whereas the modern line of APs support multi-hop or a daisy chain of wireless mesh APs. Ubiquiti offers many other networking products along with their Wi-Fi gear.

OpenMesh is all about mesh networking. Most of their mesh APs include just two radios, but the A62 does offer three radios. Since their merging with Datto, they now also include routers and switches in their networking offers.

Samsung and Cambium Networks are two more vendors that specifically market a mesh AP. Other vendors like Cisco and Aruba Networks provide mesh functionality in many of their traditional AP models.

Eric Geier is a freelance tech writer (keep up with his writings on Facebook or Twitter). He’s also the founder of NoWiresSecurity, which provides a cloud-based Wi-Fi security service, and Wi-Fi Surveyors, which provides RF site surveying.

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Thanks to Eric Geier (see source)

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