https://www.omgwiki.org/dido/ 2026-06-06T01:15:01-0400 https://www.omgwiki.org/dido/ https://www.omgwiki.org/dido/lib/tpl/dokuwiki/images/favicon.ico text/html 2021-10-04T13:40:16-0400 Anonymous (anonymous@undisclosed.example.com) https://www.omgwiki.org/dido/doku.php?id=dido:public:ra:xapend:xapend.f_qos:01_user_data&rev=1633369216&do=diff F.1 User Data Return to DDS Quality of Service The purpose of USER_DATA QoS is to allow the application to attach additional information to the created Entity objects such that when a remote application discovers their existence it can access that information and use it for its own purposes. One possible use of this QoS is to attach security credentials or some other information that can be used by the remote application to authenticate the source. In combination with operations such as text/html 2021-10-04T13:40:16-0400 Anonymous (anonymous@undisclosed.example.com) https://www.omgwiki.org/dido/doku.php?id=dido:public:ra:xapend:xapend.f_qos:11_liveliness&rev=1633369216&do=diff F.11 Liveliness Return to DDS Quality of Service The LIVELINESS policy controls the mechanism and parameters used by the Service to ensure that particular entities on the network are still “alive.” The liveliness can also affect the ownership of a particular instance, as determined by the OWNERSHIP QoS policy. text/html 2021-10-04T13:40:16-0400 Anonymous (anonymous@undisclosed.example.com) https://www.omgwiki.org/dido/doku.php?id=dido:public:ra:xapend:xapend.f_qos:deadline&rev=1633369216&do=diff F.7 Deadline Return to DDS Quality of Service The DEADLINE Policy is useful for cases where a Topic is expected to have each instance updated periodically. On the publishing side this setting establishes a contract that the application must meet. On the subscribing side the setting establishes a minimum requirement for the remote publishers that are expected to supply the data values. text/html 2021-10-03T15:31:27-0400 Anonymous (anonymous@undisclosed.example.com) https://www.omgwiki.org/dido/doku.php?id=dido:public:ra:xapend:xapend.f_qos:destination_order&rev=1633289487&do=diff F.17 Destination Order Return to DDS Quality of Service The DESTINATION_ORDER policy controls how each subscriber resolves the final value of a data instance that is written by multiple DataWriter objects (which may be associated with different Publisher objects) running on different nodes. The setting BY_RECEPTION_TIMESTAMP indicates that, assuming the text/html 2021-10-04T13:40:16-0400 Anonymous (anonymous@undisclosed.example.com) https://www.omgwiki.org/dido/doku.php?id=dido:public:ra:xapend:xapend.f_qos:durability&rev=1633369216&do=diff F.4 Durability Return to DDS Quality of Service NoteThe decoupling between DataReader and DataWriter offered by the Publish/Subscribe paradigm allows an application to write data even if there are no current readers on the network. Moreover, a DataReader that joins the network after some data has been written could potentially be interested in accessing the most current values of the data as well as potentially some history. text/html 2021-10-03T15:31:27-0400 Anonymous (anonymous@undisclosed.example.com) https://www.omgwiki.org/dido/doku.php?id=dido:public:ra:xapend:xapend.f_qos:durability_service&rev=1633289487&do=diff F.5 Durability Service Return to DDS Quality of Service The DURABILITY_SERVICE policy configures the HISTORY QoS and the RESOURCE_LIMITS QoS used by the fictitious DataReader and DataWriter used by the “persistence service.” The “persistence service” is the one responsible for implementing the DURABILITY kinds TRANSIENT and PERSISTENCE. text/html 2021-10-04T13:40:16-0400 Anonymous (anonymous@undisclosed.example.com) https://www.omgwiki.org/dido/doku.php?id=dido:public:ra:xapend:xapend.f_qos:entity_factory&rev=1633369216&do=diff F.20 Entity Factory Return to DDS Quality of Service The ENTITY_FACTORY policy controls the behavior of the Entity as a factory for other entities. This policy concerns only Domain Participant (as factory for Publisher, Subscriber, and Topic), Publisher (as factory for DataWriter), and Subscriber (as factory for DataReader). This policy is mutable. A change in the policy affects only the entities created after the change; not the previously created entities. text/html 2021-10-04T13:40:16-0400 Anonymous (anonymous@undisclosed.example.com) https://www.omgwiki.org/dido/doku.php?id=dido:public:ra:xapend:xapend.f_qos:grp_data&rev=1633369216&do=diff F.3 Group Data Return to DDS Quality of Service The GROUP_DATA QoS allows the application to attach additional information to the created Publisher or Subscriber. The value of the GROUP_DATA is available to the application on the DataReader and DataWriter entities and is propagated by means of the built-in topics. text/html 2021-10-04T13:40:16-0400 Anonymous (anonymous@undisclosed.example.com) https://www.omgwiki.org/dido/doku.php?id=dido:public:ra:xapend:xapend.f_qos:history&rev=1633369216&do=diff F.18 History Return to DDS Quality of Service The HISTORY policy controls the behavior of the Service when the value of an instance changes before it is finally communicated to some of its existing DataReader entities.If the kind is set to KEEP_LAST, then the Service will only attempt to keep the latest values of the instance and discard the older ones. In this case, the value of text/html 2021-10-03T23:27:59-0400 Anonymous (anonymous@undisclosed.example.com) https://www.omgwiki.org/dido/doku.php?id=dido:public:ra:xapend:xapend.f_qos:latency_budget&rev=1633318079&do=diff F.8 Latency Budget Return to DDS Quality of Service The LATENCY_BUDGET policy provides a means for the application to indicate to the middleware the “urgency” of the data-communication. By having a non-zero duration the Service can optimize its internal operation. This policy is considered a hint. There is no specified mechanism as to how the service should take advantage of this hint. text/html 2021-10-04T13:40:16-0400 Anonymous (anonymous@undisclosed.example.com) https://www.omgwiki.org/dido/doku.php?id=dido:public:ra:xapend:xapend.f_qos:lifespan&rev=1633369216&do=diff F.16 Lifespan Return to DDS Quality of Service The LIFESPAN QoS avoids delivering “stale” data to the application. Each data sample written by the DataWriter has an associated ‘expiration time’ beyond which the data should not be delivered to any application. Once the sample expires, the data will be removed from the text/html 2021-10-04T13:40:16-0400 Anonymous (anonymous@undisclosed.example.com) https://www.omgwiki.org/dido/doku.php?id=dido:public:ra:xapend:xapend.f_qos:ownership&rev=1633369216&do=diff F.9 Ownership Return to DDS Quality of Service The OWNERSHIP policy controls whether the Service allows multiple DataWriter objects to update the same instance (identified by Topic + key) of a data-object. There are two kinds of OWNERSHIP selected by the setting of the kind: SHARED and EXCLUSIVE. SHARED ''kind'' text/html 2021-10-03T15:31:27-0400 Anonymous (anonymous@undisclosed.example.com) https://www.omgwiki.org/dido/doku.php?id=dido:public:ra:xapend:xapend.f_qos:ownership_strength&rev=1633289487&do=diff F.10 Ownership Strength Return to DDS Quality of Service The OWNERSHIP_STRENGTH QoS policy should be used in combination with the OWNERSHIP policy. It only applies to the situation case where OWNERSHIP kind is set to EXCLUSIVE. The value of the OWNERSHIP_STRENGTH is used to determine the ownership of a data- text/html 2021-10-03T15:31:27-0400 Anonymous (anonymous@undisclosed.example.com) https://www.omgwiki.org/dido/doku.php?id=dido:public:ra:xapend:xapend.f_qos:partition&rev=1633289487&do=diff F.13 Partition Return to DDS Quality of Service The PARTITION policy allows the introduction of a logical partition concept inside the ‘physical’ partition induced by a domain. For a DataReader to see the changes made to an instance by a DataWriter, not only the Topic must match, but also they must share a common partition. Each string in the list that defines this text/html 2021-10-04T13:40:16-0400 Anonymous (anonymous@undisclosed.example.com) https://www.omgwiki.org/dido/doku.php?id=dido:public:ra:xapend:xapend.f_qos:presentation&rev=1633369216&do=diff F.6 Presentation Return to DDS Quality of Service The PRESENTATION QoS policy controls the extent to which changes to data-instances can be made dependent on each other and also the kind of dependencies that can be propagated and maintained by the Service. The setting of coherent_access controls whether the Service will preserve the groupings of changes made by the publishing text/html 2021-10-04T13:40:16-0400 Anonymous (anonymous@undisclosed.example.com) https://www.omgwiki.org/dido/doku.php?id=dido:public:ra:xapend:xapend.f_qos:reader_data_lifecycle&rev=1633369216&do=diff F.22 Reader Data Lifecycle Return to DDS Quality of Service The READER_DATA_LIFECYCLE policy controls the behavior of the DataReader with regards to the lifecycle of the data-instances it manages, that is, the data-instances that have been received and for which the DataReader maintains some internal resources. text/html 2021-10-03T15:31:27-0400 Anonymous (anonymous@undisclosed.example.com) https://www.omgwiki.org/dido/doku.php?id=dido:public:ra:xapend:xapend.f_qos:reliability&rev=1633289487&do=diff F.14 Reliability Return to DDS Quality of Service The RELIABILITY policy indicates the level of reliability requested by a DataReader or offered by a DataWriter. These levels are ordered, BEST_EFFORT being lower than RELIABLE. A DataWriter offering a level is implicitly offering all levels below. text/html 2021-10-03T23:31:27-0400 Anonymous (anonymous@undisclosed.example.com) https://www.omgwiki.org/dido/doku.php?id=dido:public:ra:xapend:xapend.f_qos:resource_linits&rev=1633318287&do=diff F.19 Resource Limits Return to DDS Quality of Service The RESOURCE_LIMITS policy controls the resources that the Service can use in order to meet the requirements imposed by the application and other QoS settings. If the DataWriter objects are communicating samples faster than they are ultimately taken by the text/html 2021-10-03T15:31:26-0400 Anonymous (anonymous@undisclosed.example.com) https://www.omgwiki.org/dido/doku.php?id=dido:public:ra:xapend:xapend.f_qos:start&rev=1633289486&do=diff Appendix F: DDS Quality Of Service Return to Reference Architecture (RA) or Return to Appendices About These are the Quality of Service (QoS) parameters defined in the main Data Distribution Service (DDS) specification. DDS Quality of Service Parameters The following list of DDS QoS parameters are listed in the order they appear in the DDS Specification rather than in Alphabetical order. (Source: text/html 2021-10-03T18:23:01-0400 Anonymous (anonymous@undisclosed.example.com) https://www.omgwiki.org/dido/doku.php?id=dido:public:ra:xapend:xapend.f_qos:time_based_filter&rev=1633299781&do=diff F.12 Time Based Filter Return to DDS Quality of Service The TIME_BASED_FILTER policy allows a DataReader to indicate that it does not necessarily want to see all values of each instance published under the Topic. Rather, it wants to see at most one change every minimum_separation period. The TIME_BASED_FILTER applies to each instance separately, that is, the constraint is that the text/html 2021-10-04T13:40:16-0400 Anonymous (anonymous@undisclosed.example.com) https://www.omgwiki.org/dido/doku.php?id=dido:public:ra:xapend:xapend.f_qos:topic_data&rev=1633369216&do=diff F.2 Topic Data Return to DDS Quality of Service The TOPIC_DATA QoS allows the application to attach additional information to the created Topic such that when a remote application discovers their existence it can examine the information and use it in an application-defined way. In combination with the listeners on the text/html 2021-10-04T13:40:16-0400 Anonymous (anonymous@undisclosed.example.com) https://www.omgwiki.org/dido/doku.php?id=dido:public:ra:xapend:xapend.f_qos:transport_priority&rev=1633369216&do=diff F.15 Transport Priority Return to DDS Quality of Service The TRANSPORT_PRIORITY QoS policy allows the application to take advantage of transports capable of sending messages with different priorities. This policy is considered a hint. The policy depends on the ability of the underlying transports to set a priority on the messages they send. Any value within the range of a text/html 2021-10-04T13:40:16-0400 Anonymous (anonymous@undisclosed.example.com) https://www.omgwiki.org/dido/doku.php?id=dido:public:ra:xapend:xapend.f_qos:writer_data_lifecycle&rev=1633369216&do=diff F.21 Writer Data Lifecycle Return to DDS Quality of Service The WRITER_DATA_LIFECYCLE policy controls the behavior of the DataWriter with regards to the lifecycle of the data-instances it manages, that is, the data-instances that have been either explicitly registered with the DataWriter using the register operations or implicitly by directly writing the data.