Methods, Communication Devices and System Relating to Performing Lawful Interception

Abstract

A method (200) performed by a communication device hosting a network element, NE, the method comprising:- preparing (202) a Report Issue request message for reporting an Issue;- incrementing (204) an Issue count to obtain a current Issue count of Issues reported by the NE to a lawful interception, LI, administrative function, ADMF;- adding (206) the current Issue count to the Report Issue request message; - sending (208) the Report Issue request message (610) including the current Issue count to the LI ADMF;-receiving (210) a request message (620) from the LI ADMF requesting information about at least one Report Issue request message sent by the NE and not received by the LI ADMF; and- sending (212) a response message (622) including the requested information.

Claims

1-24. (canceled)

25. A method performed by a communication device hosting a network element (NE), the method comprising: preparing a Report Issue request message for reporting an Issue; incrementing an Issue count to obtain a current Issue count of Issues reported by the NE to a lawful interception (LI) administrative function (ADMF), wherein the current Issue count also forms an identifier of the Issue; adding the current Issue count to the Report Issue request message; sending the Report Issue request message including the current Issue count to the LI ADMF; receiving a request message from the LI ADMF requesting information about at least one Report Issue request message sent by the NE and not received by the LI ADMF, based on comparing the current Issue count of Issues reported from the NE to the LI ADMF with a current Issue count of Issues received at the LI ADMF from the NE and determining based on the comparing that there is at least one Report Issue request message sent by the NE and not received by the LI ADMF; and sending a response message including the requested information.

26. The method of claim 25, wherein the Report Issue request message includes a Counterlssue field and the current Issue count is added in the CounterIssue field.

27. The method of claim 26, wherein the Report Issue request message is one of a ReportTasklssueRequest, ReportNEIssueRequest or a ReportDestinationlssueRequest, wherein incrementing an Issue count comprises incrementing a respective one of a TaskIssue count, an NElssue count or a DestinationIssue count, and wherein adding the current Issue count comprises adding a respective one of a current Tasklssue count, a current NElssue count or a current DestinationIssue count to the respective CounterIssue field.

28. The method of claim 25, further comprising: receiving from the LI ADMF one of a Ping request or a Keep Alive request; and sending a respective one of a Ping response or a Keep Alive response to the LI ADMF, the respective Ping response or Keep Alive response including information indicative of a current Issue count of Issues reported by the NE to the LI ADMF.

29. The method of claim 28, wherein the respective one of a Ping response or a Keep Alive response includes at least one Counterlssue field and the information indicative of a current Issue count is added in the at least one CounterIssue field.

30. The method of claim 29, wherein the respective one of a Ping response or a Keep Alive response includes a CounterTasklssue field, a CounterNElssue field and a CounterDestinationlssue field, and wherein a current Tasklssue count, a current NElssue count and a current DestinationIssue count are added in the respective said field.

31. The method of claim 25, wherein the request message is a GetAllDetails request and the response message is a GetAllDetails response.

32. The method of claim 25, wherein the request message includes at least one identifier identifying the at least one Issue reported in the at least one Report Issue message for which information is requested and the response message includes information about the at least one Issue identified by the at least one identifier.

33. A method performed by a communication device hosting a lawful interception (LI) administrative function (ADMF), the method comprising: receiving a message from a network element (NE); obtaining from the message a current Issue count of Issues reported from the NE to the LI ADMF, wherein the current Issue count also forms an identifier of the Issue; comparing the current Issue count of Issues reported from the NE to the LI ADMF with a current Issue count of Issues received at the LI ADMF from the NE; determining based on the comparing that there is at least one Report Issue request message sent by the NE and not received by the LI ADMF; sending a request message to the NE requesting information about at least one Issue reported in the at least one Report Issue request message; receiving from the NE a response message including the information about the at least one Issue reported in the at least one Report Issue request message; and incrementing the current Issue count of Issues received at the LI ADMF from the NE based on the information in the response message.

34. The method of claim 33, wherein the message received from the NE is a Report Issue request including a Counterlssue field containing the current Issue count.

35. The method of claim 34, wherein the Report Issue request is one of a ReportTasklssueRequest, ReportNElssueRequest or a ReportDestinationlssueRequest, the respective CounterIssue field including a respective one of a current Tasklssue count, a current NElssue count or a current DestinationIssue count.

36. The method of claim 33, further comprising sending one of a Ping request or a Keep Alive request to the NE and wherein the message received from the NE is a respective one of a Ping response or a Keep Alive response, the respective Ping response or Keep Alive response including information indicative of a current Issue count of Issues reported by the NE to the LI ADMF.

37. The method of claim 36, wherein the respective one of a Ping response or a Keep Alive request includes at least one CounterIssue field including the information indicative of a current Issue count of Issues reported by the NE to the LI ADMF.

38. The method of claim 36, wherein the respective one of a Ping response or a Keep Alive request includes a CounterTasklssue field including a current Tasklssue count, a CounterNElssue field including a current NElssue count and a CounterDestinationlssue field including a current DestinationIssue count.

39. The method of claim 33, wherein the request message is a GetAllDetails request and the response message is a GetAllDetails response.

40. The method of claim 33, wherein the request message includes at least one identifier identifying the at least one Issue reported in the at least one Report Issue message for which information is requested and the response message includes information about the at least one Issue identified by the at least one identifier.

41. A communication device comprising interface circuitry, at least one processor and memory comprising instructions which when performed by the at least one processor cause the communication device to perform network element (NE) operations of: preparing a Report Issue request message for reporting an Issue; incrementing an Issue count to obtain a current Issue count of Issues reported by the NE to a lawful interception (LI) administrative function (ADMF), wherein the current Issue count also forms an identifier of the Issue; adding the current Issue count to the Report Issue request message; sending the Report Issue request message including the current Issue count to the LI ADMF; receiving a request message from the ADMF requesting information about at least one Report Issue request message sent by the NE and not received by the LI ADMF, based on comparing the current Issue count of Issues reported from the NE to the LI ADMF with a current Issue count of Issues received at the LI ADMF from the NE and determining based on the comparing that there is at least one Report Issue request message sent by the NE and not received by the LI ADMF; and sending a response message including the requested information.

42. A communication device comprising interface circuitry, at least one processor and memory comprising instructions which when performed by the at least one processor cause the communication device to perform lawful interception (LI) administrative function (ADMF) operations of: receiving a message from the network element (NE); obtaining from the message a current Issue count of Issues reported from the NE to the LI ADMF, wherein the current Issue count also forms an identifier of the Issue; comparing the current Issue count of Issues reported from the NE to the LI ADMF with a current Issue count of Issues received at the LI ADMF from the NE; determining based on the comparing that there is at least one Report Issue request message sent by the NE and not received by the LI ADMF; sending a request message to the NE requesting information about at least one Issue reported in the at least one Report Issue request message; receiving from the NE a response message including the information about the at least one Issue reported in the at least one Report Issue request message; and incrementing the current Issue count of Issues received at the LI ADMF from the NE based on the information in the response message.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0043] FIG. 1 is a block diagram of an exemplary LI network and system according to prior art;

[0044] FIG. 2 is a block diagram of an exemplary LI network and system according to prior art;

[0045] FIG. 3 is a flowchart illustrating a method performed by a communication device according to embodiments;

[0046] FIG. 4 is a flowchart illustrating a method performed by a communication device according to embodiments;

[0047] FIGS. 5 and 6 are block diagrams depicting communication devices according to embodiments;

[0048] FIGS. 7 to 12 are signalling diagrams illustrating exchanges of messages in embodiments of the invention; and

[0049] FIG. 13 is a block diagram illustrating a method according to an embodiment.

DETAILED DESCRIPTION

[0050] The same reference numbers will used for corresponding features in different embodiments.

[0051] An embodiment provides a method 200 performed by a communication device hosting a network element, NE. The steps of the method 200 are illustrated in FIG. 3 and comprise: [0052] preparing 202 a Report Issue request message for reporting an Issue; [0053] incrementing 204 an Issue count to obtain a current Issue count of Issues reported by the NE to a lawful interception, LI, administrative function, ADMF; [0054] adding 206 the current Issue count to the Report Issue request message; [0055] sending 208 the Report Issue request message including the current Issue count to the LI ADMF; [0056] receiving 210 a request message from the LI ADMF requesting information about at least one Report Issue request message sent by the NE and not received by the LI ADMF; and [0057] sending 212 a response message including the requested information.

[0058] In an embodiment, the current Issue count also forms an identifier of the Issue.

[0059] In an embodiment, the Report Issue request message includes a CounterIssue field and the current Issue count is added in the CounterIssue field.

[0060] In an embodiment, the Report Issue request message is one of a ReportTasklssueRequest, ReportNEIssueRequest or a ReportDestinationlssueRequest, each having a CounterIssue field. For example, the ReportTasklssueRequest, ReportNEIssueRequest and ReportDestinationlssueRequest message formats defined in Tables 34, 36 and 38 of the ETSI TS 103 221-1 standard for the LI X1 interface may be modified to include CounterIssue fields, as illustrated in Tables 34A, 36A and 38A below:

TABLE-US-00001 Modified ReportTaskissueRequest Field Description Format M/C/ O XID See clause 5.1 See clause 5.1 M TaskReportType Type of Issue See clause 6.5.2.2 M TasklssueErrorCode Error code associated with the issue, if appropriate See clause 6.7 O TasklssueDetails Further description of issue if appropriate Free text O CounterIssue Identifier of the reported Issue Integer O

TABLE-US-00002 Modified ReportDestinationIssueRequest Field Description Format M/C/ O DID See clause 5.1 See clause 5.1 M DestinationReportType Type of Issue Same as TaskReportType, see clause 6.5.2.2 M DestinationIssueErrorCode Error code for the issue, if appropriate See clause 6.7 O DestinationIssueDetails Further description of issue if appropriate Free text O CounterIssue Identifier of the reported Issue Integer O

TABLE-US-00003 Modified ReportNElssueRequest Field Description Format M/C/ NEIssueDetails Description of issue being reported, including type of message (Warning, Fault Cleared, Fault Report) and description ErrorInformation structure (see clause 6.7) M CounterIssue Identifier of the reported Issue Integer O

[0061] In an embodiment, the step of incrementing an Issue count comprises incrementing a respective one of a TaskIssue count, an NEIssue count or a DestinationIssue count. Each of the ReportTaskIssueRequest, ReportNEIssueRequest or a ReportDestinationlssueRequest has a respective Counterlssue field and the current TaskIssue count, the current NElssue count or the current DestinationIssue count is added to the respective Counterlssue field. The count of each type of Issue is thereby separately incremented and added to the respective Report Issue request message. In terms of the tables above, for example, a current Tasklssue count would be added to the CounterIssue field in the ReportTasklssueRequest, a current NElssue count would be added to the CounterIssue field of the ReportNEIssueRequest and a current DestinationIssue count would be added to the CounterIssue field in the ReportDestinationlssueRequest.

[0062] As described above, the current Issue count forms an Identified of the respective Issue, so the TaskIssue count added to CounterIssue field in the ReportTasklssueRequest forms an Identifier of the reported TaskIssue, the DestinationIssue count added to CounterIssue field in ReportDestinationlssueRequest forms an Identifier of the reported DestinationIssue and the NElssue count added to CounterIssue field in ReportNEIssueRequest forms an Identifier of the reported NEIssue.

[0063] Corresponding embodiments relating to the Report Issue request apply to the method 300 performed by a communication device hosting an LI ADMF described below, with reference to FIG. 4.

[0064] In an embodiment, the method 200 further comprises receiving a Ping request or a Keep Alive request from the LI ADMF and sending a respective one of a Ping response or a Keep Alive response to the LI ADMF. The Ping response or Keep Alive response includes information indicative of a current Issue count of Issues reported by the NE to the LI ADMF.

[0065] In an embodiment, the Ping response or Keep Alive response includes a CounterIssue field and the information indicative of a current Issue count is added in the CounterIssue field.

[0066] For example, the PingResponse and KeepAliveResponse message formats defined in Tables 41 and 43 of the ETSI TS 103 221-1 standard for the LI X1 interface may be modified to include CounterIssue fields, as illustrated in Tables 41A and 43A below:

TABLE-US-00004 Modified PingResponse Field Description Format M/C/O OK or Error The OK response has no other content. The general errors in clause 6.7 apply. See clause 6.7 M CounterIssue Counter of the Issues Reported by NE to ADMF Integer O

TABLE-US-00005 Modified KeepAliveResponse Field Description Format M/C/O OK or Error The OK response has no other content. The general errors in clause 6.7 apply. See clause 6.7 M CounterIssue Counter of the Issues Reported by NE to ADMF Integer O

[0067] In an embodiment, the Ping response or Keep Alive response includes a CounterTasklssue field, a CounterNElssue field and a CounterDestinationlssue field and a current Tasklssue count, a current NEIssue count and a current DestinationIssue count are added in the respective field.

[0068] For example, the PingResponse and KeepAliveResponse message formats defined in Tables 41 and 43 of the ETSI TS 103 221-1 standard for the LI X1 interface may be modified to include three CounterIssue fields, one for each Issue type, as illustrated in Tables 41B and 43B below:

TABLE-US-00006 Modified PingResponse Field Description Format M/C/O OK or Error The OK response has no other content. The general errors in clause 6.7 apply. See clause 6.7 M CounterTaskIssue Counter of the TaskIssues Reported by NE to ADMF Integer O CounterNElssue Counter of the NEIssues Reported by NE to ADMF Integer O CounterDestinationIssue Counter of the DestinationIssues Reported by NE to ADMF Integer O

TABLE-US-00007 Modified KeepAliveResponse Field Description Format M/C/O OK or Error The OK response has no other content. The general errors in clause 6.7 apply. See clause 6.7 M CounterTaskIssue Counter of the TaskIssues Reported by NE to ADMF Integer O CounterNElssue Counter of the NEIssues Reported by NE to ADMF Integer O CounterDestinationIssue Counter of the DestinationIssues Reported by NE to ADMF Integer O

[0069] In an embodiment, the request message received from the LI ADMF is a GetAllDetails request and the response message sent to the LI ADMF is a GetAllDetails response. The GetAllDetails request and the GetAllDetails response messages have the format defined in the ETSI TS 103 221-1 standard for the LI X1 interface.

[0070] In an embodiment, the request message received from the LI ADMG includes at least one identifier identifying the at least one Issue reported in the at least one Report Issue message for which information is requested. The response message includes information about the at least one Issue identified by the at least one identifier.

[0071] The request message may have the message format illustrated in Table 1, below, and may be referred to as a GetReportlssueRequest message:

TABLE-US-00008 GetReportIssueRequest Field Description Format M/C/ O Reportlssueldentifiers Identifier of the reported Issues requested. String O

[0072] The Reportlssueldentifiers filed contains at least one Identifier of at least one Issue reported in the at least one Report Issue message for which information is requested, i.e. that was not received by the LI ADMF. The Reportlssueldentifiers field may contain a plurality of Identifiers as numbers and/or ranges separated by commas, for example: 1,3,5-12; the respective Identifier being the integer current IssueCount, as described above. The contents of the ReportIssueIdentifiers field may therefore be chosen to request a range of Identifiers, a list of Identifiers or a single Identifier; information about a range of Issues reported in a range of Report Issue messages not received by the LI ADMF may be requested, information about a plurality of Issues reported in a non-sequential plurality of Report Issue message not received by the LI ADMF, or information about a single Issue reported in a single Report issue message not received by the LI ADMF may thereby be requested.

[0073] The ReportIssueIdentifiers field may alternatively be left empty in which case information about all active issues is requested.

[0074] The response message may have the message format illustrated in Table 2, below, and may be referred to as a GetReportlssueResponse message:

TABLE-US-00009 GetReportIssueResponse Field Description Format M/C/ O ListOfReportTaskIssue List of requested active Task Issue List of Task issue structures O ListOfReportDestinationIssue List of requested active Destination Issue List of Destination issue structures O ListOfReportNEIssue List of requested active NE Issue List of NE issue structures O

[0075] The lists of Task issue structures, Destination issue structures and NE issue structures may be as described in Tables 34, 36 and 38 of the ETSI TS 103 221-1 standard.

[0076] An embodiment provides a method 300 performed by a communication device hosting a lawful interception, LI, administrative function, ADMF. The steps of the method 300 are illustrated in FIG. 4 and comprise: [0077] receiving 302 a message from a network element, NE; [0078] obtaining 304 from the message a current Issue count of Issues reported from the NE to the LI ADMF; [0079] comparing 306 the current Issue count of Issues reported from the NE to the LI ADMF with a current Issue count of Issues received at the LI ADMF from the NE; [0080] determining 308 based on the comparing that there is at least one Report Issue request message sent by the NE and not received by the LI ADMF; [0081] sending 310 a request message to the NE requesting information about at least one Issue reported in the at least one Report Issue request message; [0082] receiving 312 from the NE a response message including the information about the at least one Issue reported in the at least one Report Issue request message; and [0083] incrementing 314 the current Issue count of Issues received at the LI ADMF from the NE based on the information in the response message.

[0084] In an embodiment, the current Issue count also forms an identifier of the Issue.

[0085] In an embodiment, the message received from the NE is a Report Issue request including a CounterIssue field containing the current Issue count.

[0086] In an embodiment, the Report Issue request is one of a ReportTasklssueRequest, ReportNEIssueRequest or a ReportDestinationlssueRequest and the respective Counterlssue field includes a respective one of a current Tasklssue count, a current NElssue count or a current DestinationIssue count, as described above with reference to FIG. 3 and Tables 34A, 36A and 38A.

[0087] In an embodiment, the method 300 further comprises sending one of a Ping request or a Keep Alive request to the NE. The message received from the NE is a respective one of a Ping response or a Keep Alive response. The respective Ping response or Keep Alive response includes information indicative of a current Issue count of Issues reported by the NE to the LI ADMF.

[0088] In an embodiment, the respective one of a Ping request or a Keep Alive request includes a CounterIssue field including the information indicative of a current Issue count of Issues reported by the NE to the LI ADMF, as described above with reference to FIG. 3 and Tables 41A and 43A.

[0089] In an embodiment, the Ping request or Keep Alive request includes a CounterTasklssue field including a current Tasklssue count, a CounterNEIssue field including a current NElssue count and a CounterDestinationlssue field including a current

[0090] DestinationIssue count, as described above with reference to FIG. 3 and Tables 41B and 43B.

[0091] In an embodiment, the request message sent to the NE is a GetAllDetails request and the response message received from the NE is a GetAllDetails response. The GetAllDetails request and the GetAllDetails response messages have the format defined in the ETSI TS 103 221-1 standard for the LI X1 interface.

[0092] In an embodiment, the request message sent to the NE includes at least one identifier identifying the at least one Issue reported in the at least one Report Issue message for which information is requested. The response message includes information about the at least one Issue identified by the at least one identifier.

[0093] The request message may have the message format described above with reference to Table 1. The response message may have the message format described above with reference to Table 2.

[0094] An embodiment provides a method 700 of Issue reporting during lawful interception in a telecommunication network, illustrated in FIG. 13. The method of this embodiment comprises the method 200 performed by a communication device hosting a NE, as described above with reference to FIG. 3 and Tables 1, 2, 34A, 36A, 38A, 41A, 41B, 43A and 43B, combined with the method 300 performed by a communication device hosting an LI ADMF, as described above with reference to FIG. 4 and Tables 1, 2, 34A, 36A, 38A, 41A, 41B, 43A and 43B.

[0095] Referring to FIGS. 5, 7 and 8, an embodiment provides a communication device 400 comprising interface circuitry 402, a processor 404 and a data carrier 406 in the form of a memory . The interface circuitry is configured to receive requests and/or send responses between the communication device 400 and an LI ADMF (or a communication device 500 which hosts the LI ADMF).

[0096] The memory comprises instructions 408 which when performed by the at least one processor 404 cause the communication device to perform network element, NE, operations of: [0097] preparing a Report Issue request message for reporting an Issue; [0098] incrementing an Issue count to obtain a current Issue count of Issues reported by the NE to a lawful interception, LI, administrative function, ADMF; [0099] adding the current Issue count to the Report Issue request message; [0100] sending the Report Issue request message 610 including the current Issue count to the LI ADMF; [0101] receiving a request message 620 from the ADMF requesting information about at least one Report Issue request message sent by the NE and not received by the LI ADMF; and [0102] sending a response message 622 including the requested information.

[0103] In other words, the instructions may be a NE software hosted by the communication device 400, the NE software configured to perform one or more of the methods and embodiments described herein.

[0104] In an embodiment, the interface circuitry is configured to receive requests and/or send responses over an interface, X1, in accordance with the ETSI TS 103 221-1 standard for the LI X1 interface.

[0105] Referring to FIGS. 6 to 8, an embodiment provides a communication device 500 comprising interface circuitry 502, a processor 504 and memory 506. The interface circuitry is configured to receive requests and/or send responses between the communication device 500 and a NE (or a communication device 400 which hosts the NE).

[0106] The memory comprises instructions 508 which when performed by the at least one processor 504 cause the communication device to perform lawful interception, LI, administrative function, ADMF, operations of: [0107] receiving a message 610 from the network element, NE; [0108] obtaining from the message a current Issue count of Issues reported from the NE to the LI ADMF; [0109] comparing the current Issue count of Issues reported from the NE to the LI ADMF with a current Issue count of Issues received at the LI ADMF from the NE; [0110] determining based on the comparing that there is at least one Report Issue request message sent by the NE and not received by the LI ADMF; [0111] sending a request message 620 to the NE requesting information about at least one Issue reported in the at least one Report Issue request message; [0112] receiving from the NE a response message 622 including the information about the at least one Issue reported in the at least one Report Issue request message; and [0113] incrementing the current Issue count of Issues received at the LI ADMF from the NE based on the information in the response message.

[0114] In other words, the instructions may be a LI ADMF software hosted by the communication device 500, the LI ADMF software configured to perform one or more of the methods and embodiments described herein.

[0115] In an embodiment, the interface circuitry is configured to receive requests and/or send responses over an interface, X1, in accordance with the ETSI TS 103 221-1 standard for the LI X1 interface.

[0116] In an embodiment, the instructions further implement a Counter, the ADMFCounterIssue, configured to store the current Issue count of Issues received from the NE; the ADMFCounterlssue is incremented based on the information in the response message received from the NE.

[0117] Referring to FIG. 9, in an embodiment, the memory comprises further instructions 508 which when performed by the at least one processor 504 cause the communication device to perform operations of: [0118] sending a Keep Alive Request 630 to the NE, as described above with reference to FIG. 4; and [0119] receiving a Keep Alive Response 632 from the NE, as described above with reference to FIG. 4 and Tables 43A and 43B.

[0120] In other words, in this embodiment, the message 610 received from the NE is a Keep Alive Response 632.

[0121] Referring to FIG. 10, in an embodiment, the memory comprises further instructions 508 which when performed by the at least one processor 504 cause the communication device to perform operations of: [0122] sending a Ping Request 640 to the NE, as described above with reference to FIG. 4; and [0123] receiving a Ping Response 642 from the NE, as described above with reference to FIG. 4 and Tables 41A and 41B.

[0124] In other words, in this embodiment, the message 610 received from the NE is a Ping Response 642; for example, an HPPT(S) 200 OK X1 Ping Response including a CounterIssue field, as illustrated in Tables 41A and 41B above.

[0125] FIG. 11 illustrates an example exchange of Ping messages between the NE 400 and LI ADMF 500 when the LI ADMF is first connected to a NE.

[0126] When the LI ADMF is connected to the NE for the first time, the current Issue count of Issues received at the LI ADMF from the NE (the “ADMFCounterIssue”) is reset 650 to an initial value.

[0127] When the LI ADMF sends a PingRequest 640 to the NE and the NE sends a PingResponse 652 back to the LI ADMF, the PingResponse including a CounterIssue field containing the current Issue count of Issues reported from the NE to the LI ADMF (the “NECounterIssue”), as illustrated in Table 41A above.

[0128] Following sending of a first PingRequest by the LI ADMF and receipt of a first PingResponse from the NE, containing the current NECounterIssue, the LI ADMF sets 654 the ADMFCounterIssue to a valid value, i.e. the ADMF is set to the current NECounterIssue.

[0129] A corresponding message exchange can also be performed with Keep Alive messages.

[0130] Ping (or KeepAlive) messages are sent periodically when a NE is connected to an LI ADMF. After the first reception, any time a PingResponse or a KeepAliveResponse is received containing a NECounterIssue, the LI ADMF checks 658 the received NECounterIssue against the ADMFCounterIssue. If values are the same, there are no Report Issue requests sent by the NE that have not been received by the LI ADMF. If the values are not the same, i.e. the ADMFCounterIssue is lower than the received NECounterIssue, the LI ADMF determines that one or more Report Issue requests sent by the NE have not been received at the LI ADMF. The LI ADMF then sends a request message 620 to the NE requesting information about one or more Issue/s reported by the NE and not received by the LI ADMF. The LI ADMF may send a GetAllDetails request to the NE, and the NE respond with a GetAllDetails response, as described above, or the LI ADMF may send a GetReportlssueRequest and the NE respond with a GetReportlssueResponse, as described above with reference to Tables 1 and 2.

[0131] FIG. 12 illustrates an example exchange of Report Issue messages between the NE 400 and LI ADMF 500 when the NE has a new Issue to report.

[0132] The NE prepares a Report Issue request message for reporting the Issue, for example a ReportNElssue request to report an NEIssue and increments 660 the NECounterIssue by 1. The incremented NECounterIssue is added to the ReportNEIssue request in the CounterIssue field and the NE sends 662 the ReportNEIssue request to the LI ADMF.

[0133] The LI ADMF checks 664 the received CounterIssue against the current ADMFCounterIssue. If the received CounterIssue is only one greater than the current ADMFCounterIssue, no ReportIssue requests sent by the NE have not been received at the LI ADMF. The LI ADMF then sets 666 the ADMFCounterIssue to the received CounterIssue and sends 668 a ReportNEIssueResponse to the NE.

[0134] If the received Counterlssue is more than one greater than the current ADMFCounterIssue, an indicated number of Reportlssue requests have not been received by the LI ADMF and the LI ADMF must request information about one or more Issue/s reported by the NE and not received by the LI ADMF. The LI ADMF may send a GetAllDetails request to the NE, and the NE respond with a GetAllDetails response, as described above, or the LI ADMF may send a GetReportlssueRequest and the NE respond with a GetReportlssueResponse, as described above with reference to Tables 1 and 2.

[0135] The ADMF using the Reportlssue counter can know if one or more notification is lost from NE.

[0136] An embodiment provides a lawful interception system 600 in a telecommunication network, as illustrated in FIGS. 5 to 8. The system comprising a first communication device 400 hosting a NE and a second communication device hosting an LI ADMF, as described above.

[0137] Referring to FIG. 5, an embodiment provides a computer program 408 comprising instructions 410 which, when executed on a communication device 400, cause the communication device 400 to carry out the method 200 performed by a communication device hosting NE described above, with reference to FIG. 3.

[0138] Referring to FIG. 5, an embodiment provides the data carrier 406, for example memory having computer readable instructions embodied therein, the computer readable instructions for providing access to resources available on a communication device 400. The computer readable instructions comprising instructions to cause the communication device to perform the steps of the method 200 performed by a communication device hosting an NE described above, with reference to FIG. 3.

[0139] Referring to FIG. 6, an embodiment provides a computer program 508 comprising instructions 510 which, when executed on a communication device 500, cause the communication device 500 to carry out the method 300 performed by a communication device hosting an LI ADMF described above, with reference to FIG. 4.

[0140] Referring to FIG. 6, an embodiment provides a data carrier, for example memory, 506 having computer readable instructions embodied therein, the computer readable instructions for providing access to resources available on a communication device 500. The computer readable instructions comprising instructions to cause the communication device to perform the steps of the method 300 performed by a communication device hosting an LI ADMF described above, with reference to FIG. 4.