Complete Communications Engineering

VoIP communications can be captured by a lawful interception system at an ISP and distributed to authorized law enforcement destinations where the voice, video, fax and data network traffic can be decoded and interpreted. The architecture below illustrates the lawful interception apparatus and methods for a telecom traffic probe, analysis and capture of VoIP network traffic at an ISP.

VoIP Lawful Interception at Network ISP

Lawful Interception Gateway delivers VoIP network traffic captured at an IAP to the LEA

The law enforcement agency (LEA) sends a request to the lawful intercept controller (system administrator). Based on the authorized level of access for the LEA and the request, either the lawful intercept related information (IRI), content or both is then collected by the respective intercept access point (IAP) and delivered by the lawful interception gateway to the LEA for processing.

Typically, automatic sniffer programs analyze telecommunications traffic and intercept data at access points on the digital segments of PSTN and on IP networks at routers and switches using port mirroring or network taps to capture the packet data at network speeds. Either method duplicates and diverts the packets without interfering with the original data stream. Traffic analysis ensures that either the entire data stream or only those packets that satisfy the frame capture filter criteria are acquired for further processing.

When the initial call information is placed, the system can detect the event and record this information as the IRI. If the LEA is only authorized to receive the IRI, this information is passed to the LEA along with any other lawful intercept related information. If the call information is to be collected, the IRI will contain information, such as the caller ID, IP address and encoding scheme, needed to find and track the call session.

Lawful Interception Requirements

Most nations have some requirement for lawful interception compliance and reporting standards that service providers must satisfy. In the United States, the Communications Assistance for Law Enforcement Act (CALEA) requires licensed telecommunications companies including common carriers, broadband Internet access and Voice over Internet Protocol (VoIP) service providers, to support lawful intercept efforts.

Requirements may vary across national and even state boundaries. Service providers must:

Because of the sensitive nature, there are basic lawful intercept security, requirements, constraints and provisions which need to be met.

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