Exam Certified Integration Architect topic 1 question 8 discussion

A business requires automating the check and updating of the phone number type classification (mobile vs. landline) for all incoming calls delivered to its phone sales agents. The following conditions exist:
1. At peak, the call center can receive up to 100,000 calls per day.
2. The phone number type classification is a service provided by an external service API.
3. Business is flexible with timing and frequency to check and update the records (throughout the night or every 6-12 hours is sufficient).
A Remote-Call-In pattern and/or Batch Synchronization (Replication via ETL: System -> Salesforce) are determined to work with a middleware hosted on customer premise.
In order to implement these patterns and mechanisms, which component should an integration architect recommend?