The OWNERSHIP_STRENGTH QosPolicy is used to rank DataWriters of the same instance of a Topic, so that Connext DDS can decide which DataWriter will have ownership of the instance when the OWNERSHIP QosPolicy is set to EXCLUSIVE.

It includes the member in DDS_OwnershipStrengthQosPolicy. For the default and valid range, please refer to the API Reference HTML documentation.



Field Name




The strength value used to arbitrate among multiple DataWriters.

This QosPolicy only applies to DataWriters when EXCLUSIVE OWNERSHIP is used. The strength is simply an integer value, and the DataWriter with the largest value is the owner. A deterministic method is used to decide which DataWriter is the owner when there are multiple DataWriters that have equal strengths. See How Connext DDS Selects which DataWriter is the Exclusive Owner for more details.


Suppose there are two DataWriters sending DDS samples of the same Topic instance, one as the main DataWriter, and the other as a backup. If you want to make sure the DataReader always receive from the main one whenever possible, then set the main DataWriter to use a higher ownership_strength value than the one used by the backup DataWriter.


This QosPolicy can be changed at any time.

It does not apply to DataReaders, so there is no requirement that the publishing and subscribing sides use compatible values.

Related QosPolicies

Applicable Entities

System Resource Considerations

The use of this policy does not significantly impact the use of resources.

© 2018 RTI