RTI Connext DDS Micro maintains a table of destination addresses which it can send to based on information queried from the registered transports. The DDS_DomainParticipantResourceLimitsQosPolicy::max_destination_ports resource-limit is unfortunately difficult to give a precise rule for how to determine since it is transport dependent. However, as a rule of thumb the following is true:
Each network that can be reached directly by the transport requires 1 resource.
If multicast is supported it counts as 1 resource.
If the transport is the default transport (by default UDP is) it counts as one address
EXAMPLES
Consider a typical Linux computer with 2 network interfaces eth0 and lo, with support for multicast.
1 for the eth0 network.
1 for the lo network.
1 for multicast.
1 for being the default transport.
This requires 4 resources.
Consider a typical embedded computer with 1 network interfaces eth0 with no support for multicast:
1 for the eth0 network.
1 for multicast.
1 for being the default transport.
This requires 3 resources.
NOTES
The default value has been set to cover most cases. This resource-limit should only be changed if a lot of interfaces are supported (increase it) or if memory is extremely limited (decrease it).