Blocking Incoming Calls on Cisco Callmanager

Call Telemetry provides a comprehensive set of tools to block unwanted calls, and to filter calls based on reputation. This guide will walk you through the features and options available to you.

Blocked Call Number Management

The Global Block Call Table (Setup Guide) simplifies the administration of your call blocking list across Cisco Callmanager Clusters. It is an optional setting on a Policy, allowing you to choose if you want to enforce global blocks at the policy level. Instead of creating individual rules for each block, you can streamline the management process using this table across multple policies.

Administratos typically face several challenges when managing a Cisco Callmanager Environment:

• Cisco IOS Reject Rules - only allow 100 reject rules, and are not centrally managed or synchronized between CUBE routers.
• Transformation Patterns - Callmanager Incoming Calling Number Transformation patterns could be used to block calls, but require extra CSS and Partition planning, and cannot be synchronized acorss multiple clusters.
• End User Calls and Helpdesk Tickets - End Users have limited means to block calls. They typically must call the helpdesk, or create a ticket to block a call.
  • Some newer model Cisco IP Phones have a on-phone block feature, but this is not centrally managed, and can complicate the troubleshooting process by involving the end user's device in the final routing decision.
• Lack of Centralized Policy - There no centralized API access for managing your coprorate calling policies. It's difficult to manage a large block list, or to integrate with other systems for call control.
• Need for Expiring Call Block Numbers - Your Organization may not want to block a call forever. There's no way in the above native processes to create an automatic Expiration of incoming calling number blocks.
• Carriers not respecting rejected calls - Some carriers do not respect a blocked call or a rejection message, and following the SIP rejection from the CUBE or Cisco Callmanager, and will retry the call attempt, or send the call to a different CUBE. The admin wanted to block the call, but indirectly created multiple repeated attempts consuming even more resources.

The above challenges are all addressed with Call Telemetry:

• Simple CURRI API policy attachement, even across Cisco Callmanager clusters.
• Centralized management of your Organizations Global Caller block list, even across Cisco Callmanager clusters.
• Full API Access to the block list for automated call blocking scripting.
• Expiring blocked calling numbers, and the ability to set a time limit on a blocked caller.
• Multiple Self Services portals for Cisco IP Phone and Jabber user to submit their own call block submissions, and manage their own blocked caller list.
• Call Blocks can be treated as a "soft block", and redirect the call to a different number, or to voicemail - solving the issue of carriers not respecting the call rejection request.

Automatic Call Routing based on Caller ID Reputation

The best call filtering solution is the one you don't have to manage. You can leverage TrueSpam Cloud Reputation App to route calls based on reputation.

Several actions can be taken based on the reputation score of the caller ID:

• Block the incoming call
• Rename Caller ID - for example, to "Potential Spam"
• Redirect to Voicemail or another number

Watch Triggers - Monitor for Suspcious Call Activity

Watch Triggers monitor your system for unusual spikes in call volume from calling numbers. When a trigger condition is met, the calling number is added to the Watch List for review. This can be used to identify potential robocallers or attackers to block.

Learn More about Watch Lists and Triggers

Self Service Call Block Portals for Users

When spam, robocalls or unwanted calls get through, you can empower your users to submit call blocks themselves - while still having central control over the centralized block list.

Blocking Callers from Cisco IP Phones using the MCID Button - MCID Submissions

Cisco IP Phone users can tag the call as MCID by using the Cisco softkey, adding the call to the Global Block list. These are unique to the user - not system wide, and and can expire after a set amount of days, or be permanent depending on your settings.

Blocking Calls from Cisco IP Phones using the XML Sevice - Web Portal

Cisco IP Phone users can also tag calls by using the XML Service, adding the call to the Global Block list. These are also unique to the user - not system wide. The user is in full control of their own block list, among all shared lines.

Blocking Calls from Cisco Jabber Softphone - Web Portal

Jabber Users can block calls within their app via a Jabber Custom Embedded Tab. The caller is added to the Global Blocked Number list, unique to that user.

Call Block Management via API

The Global Block Call Table can be managed via API. This allows you to integrate with other systems, or to create your own custom block list management system.