Core Issue
When there are multiple partitions and calling search spaces, the route plan for the enterprise can become complex and very difficult to resolve if any issues arise at a later time.
Resolution
In many cases, the most Directory Number (DN) reachability issues are associated with duplicate DNs.
To resolve these issues, generate the route plan report and review it carefully.
The route plan report also allows you to save report data into a .csv file that you can import into other applications. The .csv file contains more detailed information than the web pages, including DNs for phones, route patterns and translation patterns.
For more information on generating and interpreting these reports, refer to these documents: