They trace the path of requests, identifying failure points.
When a network failure occurs in a distributed system, Correlation IDs allow you to follow the path of a request through various services. This helps pinpoint where the failure happened. In an e-commerce system, if a payment fails, the Correlation ID can trace the request from the frontend, through the payment gateway, to the bank API, identifying which hop caused the issue.
Additional Notes
How do Correlation IDs aid in debugging network failures?