What is an RTPS interface in RTI Connext Micro?

In RTI Connext Micro, an external RTPS interface parses RTPS messages from other DomainParticipants and passes them to an internal RTPS session based on the received GUID. Each participant creates 1 external interface.

Micro has a limit of 16 external RTPS interfaces, which implies a maximum of 16 participants can be created within 1 Micro process.

Micro is intended for resource constrained environments, and a normal Micro application needs just 1 participant. If bridging between domains, then 2 participants may be needed. Typically, only RTI tools and infrastructure services (e.g. RTI Administration Console, Routing Service, etc.) have a need to join more than 16 domains. 

If more than 16 participants need to be created in a single process, consider using RTI Connext DDS Pro.