|a sequence of octets |
Use cases for this QoS policy, as well as the DDS_TopicDataQosPolicy and DDS_UserDataQosPolicy, are often application-to-application identification, authentication, authorization, and encryption purposes. For example, applications can use Group or User Data to send security certificates to each other for RSA-type security.
In combination with DDSDataReaderListener, DDSDataWriterListener and operations such as DDSDomainParticipant::ignore_publication and DDSDomainParticipant::ignore_subscription, this QoS policy can help an application to define and enforce its own security policies. For example, an application can implement matching policies similar to those of the DDS_PartitionQosPolicy, except the decision can be made based on an application-defined policy.
The use of this QoS is not limited to security; it offers a simple, yet flexible extensibility mechanism.
Important: RTI Connext stores the data placed in this policy in pre-allocated pools. It is therefore necessary to configure RTI Connext with the maximum size of the data that will be stored in policies of this type. This size is configured with DDS_DomainParticipantResourceLimitsQosPolicy::publisher_group_data_max_length and DDS_DomainParticipantResourceLimitsQosPolicy::subscriber_group_data_max_length.
|struct DDS_OctetSeq DDS_GroupDataQosPolicy::value
a sequence of octets
[default] Empty (zero-sized)
[range] Octet sequence of length [0,max_length]