Core Issue
In very large IP telephony installations, there might be pre-programmed limits on certain software. However, Cisco CallManager has the flexibility that few other IP Telephony solutions support.
Resolution
On Cisco CallManager, there is no pre-programmed limit to the number of route patterns you can support on a Cisco CallManager server.
The actual limit is bound only by the available RAM and CPU resources on the server itself. When calculating the route patterns needed, each @ route pattern is actually a macro that expands to route 300 route patterns. The code has been tested with 1,000-plus patterns with satisfatory results.
To install Cisco CallManager, refer to your version of CallManager Release Notes to determine if there are limitations with your hardware.
To design an IP Telephony solution, refer to IP Telephony Solution Design Guides.