6. Nomenclature

6.1. DDS Router nomenclature

Payload

Raw data (no format specified) that is received and sent forward from the DDS Router.

6.1.1. Participant nomenclature

Participant

DDS Router communication Interface. It is an abstraction of DDS DomainParticipant.

This term is explained here.

Participant Name

Unique identifier of a Participant.

This term is explained here.

Participant Kind

Element that identifies a Participant kind. It can be set as a string that references an alias of an existing Participant Kind.

This term is explained here.

6.2. DDS nomenclature

DataReader

DDS element that subscribes to a specific Topic. It belongs to one and only one Participant, and it is uniquely identified by a Guid.

See Fast DDS documentation for further information.

DataWriter

DDS entity that publishes data in a specific Topic. It belongs to one and only one Participant, and it is uniquely identified by a Guid.

See Fast DDS documentation for further information.

Discovery Server

Discovery Server Discovery Protocol is a Fast DDS feature that enables a new Discovery mechanism based on a Server that filters and distribute the discovery information. This is highly recommended in networks where multicast is not available (e.g. WAN).

See Fast DDS documentation for further information.

Domain Id

The Domain Id is a virtual partition for DDS networks. Only DomainParticipants with the same Domain Id would be able to communicate to each other. DomainParticipants in different Domains will not even discover each other.

See Fast DDS documentation for further information.

DomainParticipant

A DomainParticipant is the entry point of the application to a DDS Domain. Every DomainParticipant is linked to a single domain from its creation, and cannot change such domain. It also acts as a factory for Publisher, Subscriber and Topic.

See Fast DDS documentation for further information.

Endpoint

DDS element that publish or subscribes in a specific Topic. Endpoint kinds are DataWriter or DataReader.

Guid

Global Unique Identifier. It contains a GuidPrefix and an EntityId. The EntityId uniquely identifies sub-entities inside a Participant. Identifies uniquely a DDS entity (DomainParticipant, DataWriter or DataReader).

GuidPrefix

Global Unique Identifier shared by a Participant and all its sub-entities. Identifies uniquely a DDS Participant.

Initial Peers

It is a Fast DDS Discovery Protocol that allows the router to send the discovery information directly to the Participants configured. This is highly recommended for static networks where multicast is not available (e.g. WAN).

See Fast DDS documentation for further information.

Topic

DDS isolation abstraction to encapsulate subscriptions and publications. Each Topic is uniquely identified by a topic name and a topic type name (name of the data type it transmits).

See Fast DDS documentation for further information.