The seemingly overnight success of Wi-Fi and wireless LANs (WLANs) in general is,
of course, no overnight phenomenon. Wireless LANs can trace their roots back to the
early 1980s, with experiments using infrared links, and the availability of early
spread-spectrum based peer-to-peer products in the mid-to-late ‘80s. The development of
microcells and intra-cellular handoff in the late ‘80s and early ‘90s was the next big leap forward,
mimicking the nature of wide-area cellular telephone systems, and providing a vehicle
for the cost-effective deployment of WLAN coverage over arbitrarily large areas. Next came
the release of the IEEE 802.11 standard and Wi-Fi interoperability, along with higher
throughput and lower costs. So rapid, indeed, but certainly not overnight!

Wireless LANs have achieved meaningful penetration in enterprise, public-access, and residential
settings, in applications ranging from data collection to now-ubiquitous horizontal,
general-office LAN services. We are now poised at the beginning of the next great evolutionary
step in the again hardly-overnight history of wireless LANs, and that is the introduction
of WLAN systems and products based on wireless mesh architectures. Meshes represent
a fundamental, new core direction for WLANs – they are not in any way limited to specialpurpose
deployments. We believe that meshes are also a key to large-scale,
cost-effective installations within enterprise settings.

Introducing Wi-Fi Meshes

With Wi-Fi now poised to be the network of choice within both the residence and the enterprise,
and a major element in metro-area (and perhaps beyond) venues as well, Wi-Fi-based
meshes are beginning to attract the attention of network managers. Note that a mesh need not
be based on Wi-Fi; metro-scale “macromeshes” (with perhaps several kilometers between
nodes, using appropriate radios) and even “micromeshes” used for telemetry and control applications
via very-short-range radio technologies are both available today. But the ubiquity
and low cost of Wi-Fi, along with robust market opportunities continuing to drive its technological
evolution, make Wi-Fi the vehicle of choice for many mesh applications.

A wireless mesh can be thought of as a network like any other, but with one special property:
nodes within the network can relay a connection to any other node within range (see Figure
1). One might think of this as truly a wireless switch, with traffic being redirected from node
to node in real time in response to changing traffic conditions, bandwidth prioritization, or
other network parameters. We need to draw a distinction here between infrastructure meshes
and other possible mesh structures. Most Wi-Fi meshes involve only the infrastructure part
of the network – the cells, if you will. In this approach, the need for the wiring (or backhaul)
otherwise required to interconnect access points is eliminated – all backhaul is over-the-air,
just like user traffic. This is an important and indeed critical feature of wireless meshes, because
it’s key to the cost reductions that we believe will be a major driver for the adoption of
Wi-Fi meshes in the future.