RTPS Address Location
Discovery Traffic
Discovery traffic is the traffic generated by the Participant and Endpoint Discovery Protocols(SPDP and SEDP). Discovery traffic is the traffic exchanged between the built-in endpoints.
Ports used by the built-in endpoints
| traffic type | SPDP ports | Default port number expression |
|---|---|---|
| Multicast | SPDP_WELL_KNOW_MULTICAST_PORT | PB + DG x domain_id + d0 |
| Unicast | SPDP_WELL_KNOW_UNICAST_PORT | PB + DG x domain_id + d1 + PG x participant_id |
where:
domain_id: DDS domain identifierparticipant_id: Participant identifier- PB, DG, d0 and d1: tunable parameters
- PB: port base number
- DG: domain_id gain
- d0, d1: additional offsets
The domain_id and participant_id are used to avoid conflicts among Participants on the same node. Each Participant on the same node and in the same domain must use a unique participant_id.
User Traffic
User traffic is the traffic exchanged between user-defined endpoints (e.g. non built-in endpoints).
Ports used by the user-defined endpoints
| traffic type | default port number expression |
|---|---|
| Multicast | PB + DG x domain_id + d2 |
| Unicast | PB + DG x domain_id + d3 + PG x participant_id |
where:
- PG: participant_id gain
Default Port Numbers
In order to enable out-of-box interoperability, the following default values must be used.
- PB = 7400
- DG = 250
- PG = 2
- d0 = 0
- d1 = 10
- d2 = 1
- d3 = 11
Given UDP port numbers are limited to 64K, the above default enables the use of about 230 domains with up to 120 participants per node per domain.