When You're Unaware of a Problem, You Could Be Missing More Than You Realize
CRA Call Blocking and Redirection are powerful features that provide more flexibility and management simplicity than native CUCM "Route next hop by Calling Party" Number.
To configure the CRA Call Blocking or Call Redirect feature, some Cisco CUCM side configuration is required in addition to the CRA interface config. Blocking and Redirects rely on the External Call Control Profile (ECCP) feature in CUCM.
The ECCP can be applied in two ways.
- Direct to Phone DNs - This is the simplest method and allows for differentiated block lists per phone if required in the enterprise.
- Translation and Route Patterns - This method requires some Partition/Calling Search Space knowledge but is the most efficient for screening all inbound Gateway/Trunk calls enterprise wide.
Phone DN Application
Applying a block list to specific Phone DNs is very simple. In CRA, click on Call Routing in the left navigation menu.
Select Block Calls or Redirect Calls from the top navigation menu.
Click on the 
to add a new profile.
Enter a Profile Name and Phone Number or regex pattern that you'd like to block/redirect, then click 
to complete entry. Enter as many phone numbers as you would like to block and then click 
.
Take note of the provided URL specific for this block list. You will need to input this in the CUCM ECCP.
Next, you need to complete the CUCM portion of the configuration.
In CUCM, navigate the top menu to Call Routing>External Call Control Profile.
Click 
Input the External Call Control Profile details with Name and previously provided URL in the Primary Web Service fields.
Navigate to the Directory Number that you want to apply the block list. Then Select the newly created ECCP to attach the block list.
➡️ At this point, you should be successfully blocking calls!!!
This ECCP can be manually attached to many phones if desired or via CUCM Bulk Administration (BAT). You can also add more numbers to the block list in CRA.
Confirm allowed and blocked call history in CRA under the Call Routing Log tab.
You are done. To learn more about CRA and its functionality click the link below.
