# Certified Messages

## RVCM Registration

When an RVCM listener receives its first labeled message, it registers to receive subsequent messages as certified messages. Until the registration is complete, it receives labeled messages as reliable messages. When exporting messages on a `tibrvcm` transport, we recommend either of two actions to ensure certified delivery for all exported messages:

- Create the RVCM listener before sending any messages from EMS clients.
- Pre-register an RVCM listener, either with the administration tool (see `create rvcmlistener`), or in the configuration file `tibrvcm.conf` (see `tibrvcm.conf`).

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