Last Updated on April 12, 2022

Cisco is one of the most popular unified communications platforms in the world. Many companies have deployed Cisco CUCM or CME and discovered the benefits of these systems. Cisco Call Manager enables companies to collaborate from any location via voice, video and data. Cisco also offers special technology, such as their Built-In-Bridge (BIB) feature, which facilitates call recording in Cisco powered contact centers. How does a business take advantage of these features to record calls made by their Cisco devices?

This article will discuss two common methods for call recording in a Cisco environment, how to select the recording method that best suits your company and how to configure it.

Active vs Passive call recording

Many companies face the dilemma of active vs passive when searching for a call recording solution. What is the difference and how does it impact the business?

What is Passive call recording?

A call recording method is called passive if recorded system or device does not actively participate in the recording process. The call recorder connects to the recorded phone system using a high-impedance tap or network mirror/SPAN port. This allows the recorder to monitor (or “sniff”) the call information and audio. The participants in the call are not aware about call recorder existence. The recorded device generally does not interact with the calls and the employees do not know their conversation is recorded unless management decides to communicate that information to the employees.

What is Active call recording?

A call recording method is called active when recorded system or device actively participates in the recording process. The telephone system has to provide an appropriate Computer Telephony Interface (CTI) to be used by the recorder. Call recorders use provided CTI to connect to the telephony system, usually via network, to capture call information and audio. This allows the recorder to interact with the recorded devices. Basically recorded devices “invite” the call recorder into the conversation and control recording process and recording content.

What are the common call recording methods?

Cisco provides three different approaches to setup call recording.

1. Switched Port Analyzer (SPAN) – is often referred as mirror port, commonly used to monitor and record network traffic. This passive recording method allows the recorder to analyze the network traffic to filter out and record VoIP call content. Port mirroring is used to send a copy of the network traffic to specific SPAN port connected to the recorder. The recorder filters out needed traffic and saves as audio recording files.
   
2. Built-In-Bridge (BiB) – is often referred as CUCM phone fork-based recording which uses the conferences bridge that is built in to the Cisco device. When CUCM is properly configured, the Cisco device forks the call audio to a recording software that saves the audio file. This eliminates the need to configure a SPAN port for select Cisco devices and allows recording from multiple sites into a centralized recorder.
   
3. Cisco Unified Border Element (CUBE) – is software that runs on a Cisco Integrated Services Router (ISR). The methodology is similar to BiB, however; the media is forked by the CUBE software that runs on the Cisco ISR.
   

How to setup Mirror/SPAN port?

Port mirroring is a method to monitor network traffic. The setup requires a switch that supports port mirroring. The switch delivers a copy of the data packets from one port to another for analysis. Refer to your switch documentation for the mirror port configuration instructions.

How do switches work?

A switch is a device that contains multiple ports and can interconnect multiple devices. Switches allow packets to be delivered to specific devices connected to their ports. For example, imagine a switch with three computers A, B and C connected to corresponding ports. If computer A wants to deliver a data packet to computer C, the switch routes the packet specifically to the port where computer C is connected. This transaction is completely hidden from computer B. Traffic is only visible to the computers that participate in the transaction.

Switches that support port mirroring allows an additional device to the system, computer D. An administrator may configure the switch make a copy of all network packets transmitted between computers A and C to computer D. Computer D becomes a listener and may be used for passive call recording.

For samples of the passive recording configurations, see Call Recording Scenario #3.

and Scenario #5.

How to setup recording via Built-In-Bridge (BiB)

There is a conference bridge embedded in some models of Cisco IP phones and Cisco Jabber for Windows. Business managers may configure CUCM to have the Cisco IP phone fork the call audio to the call recorder. This removes the need to configure a SPAN mirror port in the network switch and allows the recording of phones from multiple locations to central recorder. To setup this configuration, there are three requirements.

1. Create recording profile on CUCM
   
2. Configure Versadial Call Recorder to act as a SIP trunk for the CUCM
   
3. Link recording profile to SIP Trunk (Router Pattern UCM)
   

For detailed installation instruction, see Versadial’s Cisco BiB/JTAPI Configuration documentation. In summary, the administrator must create a recording profile in the CUCM. When the profile has been created, the administrator assigns it to all recorded Cisco IP phones. During the setup, the Versadial recorder is configured as a SIP Trunk and a route pattern is assigned. The profile is then linked to the SIP trunk using the same route pattern assigned in the CUCM. The CUCM sends calls to the Versadial call recorder to be recorded when an actual call takes place.

For more details about this setup, see Call Recording Scenario #9.

How to record calls using Cisco Unified Border Element (CUBE)

A CUBE configuration for call recording uses the same forking premise as BiB. The difference is, the forking occurs on the ISR. This configuration is known as Session Recording Protocol (SIPREC). The CUBE takes the role as a Session Recording Client while the Versadial call recorder behaves as the Session Recording Server. When an actual call takes place, a copy of the media stream is sent to the call recorder. Metadata is passed by the CUBE and describes the communication session, media stream and identifies the call participants.

For more details about this setup, see Call Recording Scenario #17.

How to determine the best call recording approach.

In general, companies should pursue BiB recording with all devices that can support built-in-bridge. This technology provides detailed call information and is highly reliable. Use CUBE recording if the router supports media forking and there are no devices that provide BiB. Use SPAN in all other cases.

Every company has different equipment and call recording objectives. Business managers should assess their environment and determine the call recording approach that best fits their situation. Contact us for assistance with determining the best solution for your business.

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Last Updated on April 12, 2022