WLAN modes:
Let’s have here a quick overview of the different
modes Wi-Fi adapters can be configured :
-Infrastructure Master (Access Point)
-Infrastructure Managed (Adapter/Bridge)
-Ad-hoc without routing algorithm
-Ad-hoc with the OLSR routing algorithm
(Mesh Networking)
In infrastructure mode we have a master/slave
structure where all the data is centralized in one
device called access point (server/master) to which
different adapters (clients/slaves/managed) connect.
A client cannot talk directly to another but has to
pass by the access point which will forward the data
to the destination. Several access points can be
connected together with cables extending in this way
the zone covered by the wireless network. This is the
most common setup for a Wi-Fi network (see
Fig1
).
In ad-hoc mode we do not have any central
management, each client can talk directly to the
other. This mode works fine for networks with few
elements. Without any routing algorithm, each
element needs to have a direct radio link with the
others in order to communicate, no data will be
forwarded (see
Fig2
). If a routing algorithm such as
OLSR is added, you obtain a self-organizing mesh
network in which message forwarding is possible
wirelessly between different nodes, connecting in
this way devices which are not within direct radio
range (see
Fig3
). This allows to extend the zone
covered without the need of any cable.The network
is completely dynamic, routing tables are rewritten
automatically and dynamically as the network
changes. If a new OLSR enabled device appears, it
will be automatically detected and merged to the
routing tables of each node. This is especially useful
for mobile networks that can change over time like
for example in a multi-robot application.
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Fig 1
Fig 2
Fig 3