As an ITSP you may be requested to enable law enforcement agencies to monitor a certain subscriber’s calls. This may be required in accordance with the Communications Assistance for Law Enforcement Act of 1994 (CALEA) or some other law applicable in the country where you provide services.
You can activate the Legal intercept call feature in PortaBilling for every account that requires it (obviously, this feature is only accessible from the administrator interface, and is not visible to the end user). When this is done, PortaSIP will be instructed to engage the RTP proxy for every outgoing or incoming call to this account, regardless of other NAT traversal settings, and will produce a complete call recording of the conversation.
An administrator can search for Legal intercept recordings for a particular account when their xDRs are present in the system. By default, the xDRs are kept in the system for 2 months. Thus, if according to CALEA requirements, you must provide Legal intercept recordings that are older than 2 months (e.g., for 4 months), specify the xDR storage period in the keep_month parameter on the Configuration server.
Keep in mind that keeping xDRs for a long period occupies more disc space.
The call recordings may then be delivered to the law enforcement agency by any applicable means, or you may even provide real-time access to the location on the PortaSIP server where these files are stored.
In the specific case of CALEA, there are many requirements which an ITSP must comply with, many of them not even related to technical capabilities, but rather purely to administration, e.g., personnel dealing with intercept data must have an appropriate security clearance. So the optimal solution for ITSPs using PortaSwitch is another option described by CALEA, e.g., going via a "trusted third party". PortaSwitch has been tested with the “Just in Time” product from the NeuStar's Fiduciary Services (now Subsentio). For more information about the CALEA compliance for legal intercept, please contact Subsentio.