ENUM Database Update
When a REGISTER message is received:
- The ENUM user database is queried for the AoR and any existing entries.
- If there are any entries with the same instance-id as the current REGISTER request in the ENUM query response, then those entries will be marked for subsequent removal in the ENUM database.
- The ENUM database is updated with a NAPTR request. This request adds the new Contact URI for that AOR+instance-id and removes any existing entries for the same AOR+instance-id.