Lawful interception
AssigneeTelefonaktiebolaget LM Ericsson (publ)
InventorsMario Ascione, Andrea Senatore, Francesco Toro
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Abstract
A mediation function receives intercepted signaling and media payload messages from an IP Multimedia Subsystem, IMS. Local correlation numbers (304) are calculated and a table (300) comprising correlation numbers (304) and media payload mapping information (306) is maintained in order to enable the mediation function to provide a law enforcement agency, LEA, with intercepted media payload together with information that enables the LEA to decode the media payload in real-time.
Claims18
A method, performed by a mediation function, for handling lawful interception (LI) information that is being intercepted in an internet protocol multimedia subsystem (IMS), the method comprising:
- receiving a plurality of signaling messages from the IMS, each message comprising information that defines an identity of an intercepted entity and a mapping information value that comprises a mapping of a media payload type number to a media encoding name that identifies a media payload format;
- calculating a respective first correlation number associated with respective identities of the intercepted entities;
- storing the first correlation numbers and the mapping information values such that a table is maintained;
- the table comprising records, each record comprising a correlation number and at least one corresponding mapping information value;
- receiving a plurality of media messages from the IMS, each message comprising information that defines an identity of an intercepted entity, media payload, and a media payload type number associated with the media payload;
- calculating, based on the received media messages, a respective second correlation number associated with respective identities of the intercepted entities;
- extracting, from the table and for each received media message, a mapping information value corresponding to the second correlation number and corresponding to the media payload type number;
- and
- transmitting, to a law enforcement agency (LEA) and for each received media message, a message comprising:
- the media payload of the received media message;
- and
- a media encoding name comprised in the extracted mapping information value.
A mediation function apparatus for handling lawful interception (LI) information that is being intercepted in an internet protocol multimedia subsystem (IMS), the mediation function apparatus comprising:
- processing circuitry;
- memory containing instructions executable by the processing circuitry whereby the mediation function apparatus is operative to:
- receive a plurality of signaling messages from the IMS, each message comprising information that defines an identity of an intercepted entity and a mapping information value that comprises a mapping of a media payload type number to a media encoding name that identifies a media payload format;
- calculate a respective first correlation number associated with respective identities of the intercepted entities;
- store the first correlation numbers and the mapping information values such that a table is maintained;
- the table comprising records, each record comprising a correlation number and at least one corresponding mapping information value;
- receive a plurality of media messages from the IMS, each message comprising information that defines an identity of an intercepted entity, media payload, and a media payload type number associated with the media payload;
- calculate, based on the received media messages, a respective second correlation number associated with respective identities of the intercepted entities;
- extract, from the table and for each received media message, a mapping information value corresponding to the second correlation number and corresponding to the media payload type number;
- and
- transmit, to a law enforcement agency (LEA) and for each received media message, a message comprising the media payload of the received media message and comprising a media encoding name comprised in the extracted mapping information value.
A non-transitory computer readable recording medium storing a computer program product for handling lawful interception (LI) information that is being intercepted in an internet protocol multimedia subsystem (IMS), the computer program product comprising software instructions which, when run on processing circuitry of a mediation function, causes the mediation function to:
- receive a plurality of signaling messages from the IMS, each message comprising information that defines an identity of an intercepted entity and a mapping information value that comprises a mapping of a media payload type number to a media encoding name that identifies a media payload format;
- calculate a respective first correlation number associated with respective identities of the intercepted entities;
- store the first correlation numbers and the mapping information values such that a table is maintained;
- the table comprising records, each record comprising a correlation number and at least one corresponding mapping information value;
- receive a plurality of media messages from the IMS, each message comprising information that defines an identity of an intercepted entity, media payload, and a media payload type number associated with the media payload;
- calculate, based on the received media messages, a respective second correlation number associated with respective identities of the intercepted entities;
- extract, from the table and for each received media message, a mapping information value corresponding to the second correlation number and corresponding to the media payload type number;
- and
- transmit, to a law enforcement agency (LEA) and for each received media message, a message comprising:
- the media payload of the received media message;
- and
- a media encoding name comprised in the extracted mapping information value.
Dependencies are inferred from the claim text.