User's Guide

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As an example: A network with 1000’s of wireless NeoMesh enabled sensors, is
configured such that the sensors sends measurement samples periodically to a gateway
node in the network. All of the sensor devices are non-sink nodes. The gateway once in
a while has to send messages to the individual sensors. It can do so by waiting until a
message has been received from the sensor to which it needs to send data. At this time,
a backward route exists and can be used for sending the message to the non-sink
sensor.
Note: This method of sending messages to non-sink nodes is only useful in static
networks, as the backward routes are only valid while the network stays stationary.
Similarly, there is a limit for the maximum number of concurrent backward routes, and
old routes will be exchanged for new routes. This means, that the backward route will
disappear after a while. The validity period of a backward route is determined by the
total number of devices in the network, and the frequency of payload transmissions. In
general, backward routes shall only be used within a few multiples of 10 Scheduled
Data periods after they have been created.
3.3.4.4 Broadcast Transmissions
Broadcast Transmissions can either be unicast or groupcast. There is however no
filtering for groupcast messages in the protocol layer, and as such the application layer
will have to filter out groupcast messages which are non-relevant based on the group
ID.
Broadcast Transmissions is a special type of Non-Acknowledged transmissions where
Speed Routing is not being used. Instead, the messages are flooded into the network
and as such all devices will receive them. Notice that this is not limited to sink nodes –
non-sink nodes will receive these messages as well.
Broadcast Transmissions are particular useful in situations where the same information
needs to be transmitted to all – or a group of devices.
Broadcast messages are stored in all nodes until they expire (a setting controls the Time
To Live). If new nodes join the network while broadcast messages are still present (not
yet expired), they will be delivered to the newly joined node.
3.3.4.5 Payload transmission method
Regardless of which transmission type is being used, payload data is being transmitted
from node to node through the network, as part of the normal Scheduled Data
transmissions.