Mesh

Finally we will consider the mesh, the least utilized network architecture to date, but by some
accounts the most promising.
A mesh substandard is included in 802.16a based largely on the technology Nokia Corporation
purchased from Rooftop Communications. None of the current proponents of mesh
networks for broadband wireless deployments follow that substandard.
A mesh would appear to be the most expensive architecture to build—though manufacturers
of mesh equipment dispute this—because each node requires a router. It also appears
to be the most robust because each node has multiple pathways available to it. Since deployments
have been so few, it is difficult to ascertain the real business case for mesh architectures,
and it is equally difficult to determine when a mesh would be indicated over point-tomultipoint.
The argument in the past in favor of the mesh was that individual base stations in a point-to-multipoint architecture could not access all potential customers because of lineof-
sight limitations, but with the introduction of NLOS equipment that contention appears
considerably less persuasive today. On the other hand, a mesh almost eliminates the need for
backhaul, which, in many cases, is the biggest cost in setting up a wireless broadband network.
Conceptually the mesh architecture is intriguing and, if one takes the concept to its logical
extreme, suggests a fundamentally different way of structuring a communications system, not
just on the access level but at all levels. A pure mesh—sometimes called a fractal mesh because
its gross structure resembles its fine structure—is essentially nonhierarchical; in other words,
it forms a homogenous organization where distinctions between the LAN, the metro, and the
long haul disappear as well as distinctions between subscriber terminal and network access
point. Since network intelligence is distributed through the network and is self-organizing,
there is no need for base stations, central offices, or large routers or switches to manage the
network. Billing and provisioning still have to be centrally managed, assuming that the network
is a for-profit enterprise and not a cooperative venture, but the basic hub-and-spokes or
tree-and-branches structure typifying all traditional communications networks is no longer
present and plays no part in the distribution of information through the network for the execution
of management and system support functions. Figure 4-5 shows a mesh architecture.