Your browser is not supported. Please update it.

18 October 2017

Mesh carries WiFi to the whole-home frontier, but lacks standards

WiFi has been sweeping to power in the home, but still has one final hurdle to jump in order to oust wired options completely. It still cannot be relied on to deliver guaranteed whole-home connectivity for premium video across a wide range of building types and sizes. It can provide that quality within a room but, especially in large buildings or where walls are made of thick stone or contain a lot of metal, it cannot span multiple rooms without wired assistance. Mesh has emerged as a solution to this issue, and many vendors now have solutions – but that has created a new problem, that of interoperability between many proprietary approaches.

Until WiFi mesh emerged, even those pay-TV operators which are strong advocates of WiFi had to fall back on one of the wired options, such as Ethernet over twisted pair, powerline over electricity cables, or MoCA over coaxial cable. In the UK, for instance, Sky uses powerline as a backbone – or more correctly back-up – for its Sky Q home network platform.

The main Sky Q set-top is typically in the living room near the main TV, connected over WiFi to satellite Sky Q mini boxes in other rooms. However powerline connections are configured to kick in if the WiFi signal dips below a given strength, or can be used all the time. The Sky Q Mini boxes can also operate as WiFi extenders or access points (APs) within a mesh network, using technology from Turkish WiFi specialist AirTies with the plan being to dispense with the need for powerline altogether.

Propelled by mesh and other enhancements, WiFi has made huge recent inroads in both Europe and North America, two regions where for different reasons it was initially held back. In North America this was because MoCA had a head start because so many buildings come ready cabled with coax, while in Europe there are a lot of buildings with thick walls and a lot of stone or brick that impede radio signal propagation between rooms.

Given that mesh is essential for solving the WiFi QoS problem and is also complex to tune for optimal performance, capacity and resiliency, it has become a hotbed of competition and innovation drawing in at least 70 vendors, with leaders including Linksys, Netgear, Mojo Networks, Cisco, Meraki, HP’s Aruba, Zebra Technologies, Meru, Ruckus, Eero and Ubiquity, besides AirTies.

Complementary technologies have also evolved to exploit features of WiFi, notably band steering to route traffic between the two current spectral bands, 2.4 GHz and 5 GHz, and client steering to connect clients to the optimum AP on the basis of signal strength and current traffic load.

Some have also added high level management capabilities that optimize mesh operation, including client and band steering for the benefit of the whole wireless network rather than just individual devices. This also involves tackling the so called ‘bad apple’ problem in which one legacy device, not capable of operating at the same bit rate as newer devices, hogs network access time at the expense of others.

Essentially mesh makes WiFi operate more like a fixed point-to-point network, providing a firmer foundation for end-to-end SLAs. But this proliferation of mesh vendors, while providing choice, is also a problem because none of the mesh technologies is interoperable.

It is true that most support the IEEE 802.11s standard for mesh, but this only covers link level communication within a point-to-point WiFi network so that different vendors’ devices can participate in a given mesh implementation. This has led to demand for higher level mesh standards and the next step is currently being plotted by several standards groups on the video side, such as CableLabs, as well as the WiFi Alliance.

This is leading towards a standard AP Coordination Protocol, which may end up being called Multipath AP. It has been knocking around at least a decade in academic circles but has only in the last couple of years been taken up urgently by the standards bodies.

This attempts to standardize not so much the higher level mesh management but client steering. It allows APs in a home network to share the relevant information to make intelligent steering decisions, alongside some other network maintenance tasks.

But the focus is still on individual APs rather than the connected whole. As James Chen, senior director of marketing at WiFi chip maker Quantenna, pointed out recently at IBC 2017, this still leaves plenty of room for mesh specialists to innovate and does not yet tread on their toes too much.

In fact, Quantenna itself has integrated AirTies’ mesh middleware into its chips, as well as its own self-optimizing network software, SONiQ, which also supports more traditional star-shaped repeater topologies. The objective is to give Quantenna’s customers such as router, set-top and gateway makers, a choice of mesh algorithm and most likely others will be added.

But Chen did issue a more chilling sentiment for mesh vendors when he suggested that mesh was becoming too important and too integral to the operation of WiFi, as it supports premium video, to be left to proprietary technologies which crucially do not interoperate. He suggested that it would only be a matter of time before a full mesh standard emerged covering the whole network and that Quantenna’s embrace of different third party software might only be temporary.

Even a common mesh standard would not on its own solve all WiFi’s problems, because it would still, as it stands, rely in many cases on consumers exercising due diligence in their deployment and network configuration. However this loophole has actually been closed, for new builds at any rate, by the WiFi Alliance’s certification program for new homes, unveiled in June 2017.

Called WiFi Certified Home Design, this defines what the Alliance called enterprise grade standards for planning and installing WiFi networks in new homes. This would lead to integrated WiFi networks configured to an industry-approved network installation plan based on exacting WiFi deployment guidelines.

Although this will naturally have to evolve as mesh standards are defined, it looks like answering the prayer of many operators which have been tearing their hair out over having to support ad hoc WiFi networks over which they have little control. With WiFi built into the fabric of the home to agreed configuration standards defining where APs are stationed for example, it becomes more like a wired extension of the operator’s broadband network.