Multicast

[troelsjessen]

I have done a test implementation, but first of all we must find out, if adding more broadcast address is a adequate solution for use with param_publish.

The feature is implemented by extending the number of nodes allocated for broadcast on selected nodes (typically OBCs)

AOCS OBC requirements
Listening for typically small unsolicited packets, coming with high frequency

HK/FDIR OBC requirements
Cover larger incoming packets, coming with a lower frequency
Will often collect data published for AOCS also

Broadcast size 1 (default, and only option today) is used for most nodes, to allow a client to request all nodes to reply to e.g. an ident request.

Broadcast size 2 will be used by the Space Inventor AOCS processing nodes, which will allow unsolicited data messages from sensors to arrive at multiple AOCS instances without requiring an explicit data request, and without having the sensor data multiplied on the bus for each recipient.

Broadcast size 3 will be used by the Space Inventor OBCs responsible for collecting log and health data. Nodes will send messages for expected or unexpected events (e.g. MCU reboot, undervoltage). The OBC collecting this data, will implicitely also receive sensor data intended for AOCS usage.