User's Manual

Rajant Corporation ME BreadCrumb User Guide
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2.1.5 ANY COMBINATION OF THE ABOVE
Most BreadCrumb deployments include elements from more than one of the above scenarios.
In many cases, BreadCrumb devices will perform all of the above tasks as shipped with no
configuration necessary at all, providing an instant TAN -a Tactical Area Network.
Moreover, because BreadCrumb devices use industry-standard 802.11b communications,
client devices such as laptops or handheld computers require no special hardware, software,
or configuration to access a BreadCrumb Wireless Network.
2.2 MOBILITY THROUGH MESHING
The key component to a BreadCrumb Wireless Network is a technique known as Meshing.
While this is generally handled automatically by BreadCrumb devices, complex deployment
scenarios require a basic understanding of how BreadCrumb devices establish and maintain a
mesh.
2.2.1 MESH – A DEFINITION
A mesh is a collection of network devices (in our case, BreadCrumb devices), each of which
is connected to one or more other BreadCrumb devices. Data can move between
BreadCrumb devices via these links, possibly passing through several intermediate
BreadCrumb devices before arriving at its final destination.
The intelligence of a BreadCrumb Wireless Network is in how it adapts rapidly to the
creation or destruction of the links in the mesh as devices are moved, switched OFF or ON,
blocked by obstructions, interfered with by other devices, or otherwise affected. This
adaptation takes place automatically and immediately as needed.
Note: Although all BreadCrumb devices can be Access Points, most Access Points do not
provide any meshing capabilities. Traditional Access Points simply allow wireless devices
within range to connect to a wired network; they do not extend range through other Access
Points.
2.2.2 BREADCRUMB DEVICES MESH BY CHANNEL AND ESSID
Two BreadCrumb devices establish a mesh link to one another when they share both a radio
channel and an ESSID. The 802.11b radios used by BreadCrumb devices support 11 different
channels for communication, numbered 1-11. By default, each BreadCrumb device radio is
on channel 1, 8, or 11. Most BreadCrumb devices have two radios, using two of those
channels.
An ESSID is essentially a name for a wireless network. By default, BreadCrumb devices use
the ESSID "breadcrumb".
Example 1
Suppose you have three BreadCrumb devices, called A, B, and C. Each has two radios.
BreadCrumb device A’s radios are on channels1 and 8, B’s are on 8 and 11, and C’s are on 1
and 11. All three BreadCrumb devices are using the default ESSID of "breadcrumb".
Assuming that all three BreadCrumb devices are within radio range of one another, the
network will be connected like this: ????