ETSI TS 102 232-5 V3.10.1 (2019-04)

TECHNICAL SPECIFICATION
Lawful Interception (LI);
Handover Interface and
Service-Specific Details (SSD) for IP delivery;
Part 5: Service-specific details for IP Multimedia Services


2 ETSI TS 102 232-5 V3.10.1 (2019-04)

Reference
RTS/LI-00167-5
Keywords
IMS, IP, lawful interception, security
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3 ETSI TS 102 232-5 V3.10.1 (2019-04)
Contents
Intellectual Property Rights . 5
Foreword . 5
Modal verbs terminology . 5
Introduction . 5
1 Scope . 6
2 References . 6
2.1 Normative references . 6
2.2 Informative references . 7
3 Definition of terms, symbols and abbreviations . 7
3.1 Terms . 7
3.2 Symbols . 8
3.3 Abbreviations . 8
4 General . 9
4.1 Reference Model for Lawful Interception . 9
4.2 Reference system model . 10
4.2.0 Overview . 10
4.2.1 Network layer Interception . 11
4.2.2 Service layer Interception . 11
4.3 General Requirements . 12
5 Interception of IP Multimedia services . 12
5.1 Identification of target of interception . 12
5.1.1 SIP Target Identification . 12
5.1.2 H.323 Target Identification . 13
5.1.3 Other Target Identifiers . 13
5.2 Interception of signalling . 13
5.2.1 Provisioning of the SIP IRI IIF . 13
5.2.2 Provisioning of the H.323 IRI IIF . 13
5.2.3 Location information . 13
5.2.4 Supplementary Services . 13
5.2.5 Additional signalling information . 14
5.3 Assigning a value to the Communication Identity Number . 14
5.3.0 Introduction. 14
5.3.1 Assigning a CIN value to SIP related IRI . 14
5.3.2 Assigning a CIN value to H.323 related IRI . 14
5.4 Events and IRI record types . 14
5.5 Interception of Content of Communication . 15
5.6 Direction for IMS IRI for Signalling Messages . 16
5.7 Direction for IMS sessions . 16
5.7.1 Direction for SIP sessions . 16
5.7.2 Direction for H.323 sessions . 16
6 Handover Interface . 16
6.1 Intercepted Related Information . 16
6.2 Correlation of IRI and CC . 17
7 ASN.1 specification for IRI and CC. 17
Annex A (informative): Interception using H.248 . 20
A.1 Purpose of this annex . 20
A.2 Notes on interception using H.248 . 20
A.2.1 Target identification (see also clause 5.1) . 20
A.2.2 Provisioning of the H.248 IRI IIF (see also clause 5.2) . 21
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4 ETSI TS 102 232-5 V3.10.1 (2019-04)
A.3 Problems in H.248 interception . 21
A.3.1 Missing information in H.248 signalling . 21
A.3.2 Missing call content. 22
Annex B (normative): Minimum set of functional attributes to be provided . 23
B.0 Overview . 23
B.1 General requirements . 23
B.2 Result of interception . 24
B.3 Location information . 24
B.4 Time constraints . 24
B.5 Technical handover interfaces and format requirements . 25
Annex C (informative): Change request history . 26
History . 29

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5 ETSI TS 102 232-5 V3.10.1 (2019-04)
Intellectual Property Rights
Essential patents
IPRs essential or potentially essential to normative deliverables may have been declared to ETSI. The information
pertaining to these essential IPRs, if any, is publicly available for ETSI members and non-members, and can be found
in ETSI SR 000 314: "Intellectual Property Rights (IPRs); Essential, or potentially Essential, IPRs notified to ETSI in
respect of ETSI standards", which is available from the ETSI Secretariat. Latest updates are available on the ETSI Web
server (https://ipr.etsi.org/).
Pursuant to the ETSI IPR Policy, no investigation, including IPR searches, has been carried out by ETSI. No guarantee
can be given as to the existence of other IPRs not referenced in ETSI SR 000 314 (or the updates on the ETSI Web
server) which are, or may be, or may become, essential to the present document.
Trademarks
The present document may include trademarks and/or tradenames which are asserted and/or registered by their owners.
ETSI claims no ownership of these except for any which are indicated as being the property of ETSI, and conveys no
right to use or reproduce any trademark and/or tradename. Mention of those trademarks in the present document does
not constitute an endorsement by ETSI of products, services or organizations associated with those trademarks.
Foreword
This Technical Specification (TS) has been produced by ETSI Technical Committee Lawful Interception (LI).
The present document is part 5 of a multi-part deliverable. Full details of the entire series can be found in part 1 [2].
The ASN.1 module is also available as an electronic attachment to the original document from the ETSI site (see
clause 7 for details).
Modal verbs terminology
In the present document "shall", "shall not", "should", "should not", "may", "need not", "will", "will not", "can" and
"cannot" are to be interpreted as described in clause 3.2 of the ETSI Drafting Rules (Verbal forms for the expression of
provisions).
"must" and "must not" are NOT allowed in ETSI deliverables except when used in direct citation.
Introduction
The present document focuses on Lawful Interception of IP Multimedia Services. It is to be used in conjunction with
ETSI TS 102 232-1 [2], in which the handling of the intercepted information is described.
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6 ETSI TS 102 232-5 V3.10.1 (2019-04)
1 Scope
The present document specifies interception of Internet Protocol (IP) Multimedia (MM) Services based on the Session
Initiation Protocol (SIP) and Real Time Transport Protocol (RTP) and Message Session Relay Protocol (MSRP) and IP
MM services as described by the Recommendations ITU-T H.323 [6] and H.248 [7].
The present document is consistent with the definition of the Handover Interface, as described in ETSI
TS 102 232-1 [2].
The present document does not override or supersede any specifications or requirements in ETSI TS 133 108 [9] and
ETSI TS 101 671 [1].
2 References
2.1 Normative references
References are either specific (identified by date of publication and/or edition number or version number) or
non-specific. For specific references, only the cited version applies. For non-specific references, the latest version of the
referenced document (including any amendments) applies.
Referenced documents which are not found to be publicly available in the expected location might be found at
https://docbox.etsi.org/Reference.
NOTE: While any hyperlinks included in this clause were valid at the time of publication, ETSI cannot guarantee
their long term validity.
The following referenced documents are necessary for the application of the present document.
[1] ETSI TS 101 671: "Lawful Interception (LI); Handover interface for the lawful interception of
telecommunications traffic".
NOTE: ETSI TS 101 671 is in status "historical" and is not maintained.
[2] ETSI TS 102 232-1: "Lawful Interception (LI); Handover Interface and Service-Specific Details
(SSD) for IP delivery; Part 1: Handover specification for IP delivery".
[3] Recommendation ITU-T X.680: "Information technology - Abstract Syntax Notation One
(ASN.1): Specification of basic notation".
[4] IETF RFC 3261: "SIP: Session Initiation Protocol".
[5] IETF RFC 3550: "RTP: A Transport Protocol for Real-Time Applications".
[6] Recommendation ITU-T H.323: "Packet-based multimedia communications systems".
[7] Recommendation ITU-T H.248: "Gateway control protocol".
NOTE: H.248 was renumbered when revised on 2002-03-29. H.248 main body, Annexes A to E and Appendix I
were included in H.248.1. Subsequent annexes were sequentially numbered in the series, e.g. H.248
Annex F became H.248.2.
[8] Void.
[9] ETSI TS 133 108: "Universal Mobile Telecommunications System (UMTS); LTE; 3G security;
Handover interface for Lawful Interception (LI) (3GPP TS 33.108).
[10] ETSI TS 101 331: "Lawful Interception (LI); Requirements of Law Enforcement Agencies".
[11] ATIS-PP-1000678.2006: "Lawfully Authorized Electronic Surveillance (LAES) for Voice over
Packet Technologies in Wireline Telecommunications Networks", Version 2 (Revision of
T1.678-2004).
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7 ETSI TS 102 232-5 V3.10.1 (2019-04)
[12] Recommendation ITU-T H.225.0: "Call signalling protocols and media stream packetization for
packet-based multimedia communication systems".
[13] Recommendation ITU-T H.245: "Control protocol for multimedia communication".
[14] Void.
[15] IETF RFC 4975: "The Message Session Relay Protocol (MSRP)".
[16] Recommendation ITU-T T.38: "Procedures for real-time Group 3 facsimile communication over
IP networks".
[17] IETF RFC 4825: "The Extensible Markup Language (XML) Configuration Access Protocol
(XCAP)".
[18] ETSI TS 124 623: "Digital cellular telecommunications system (Phase 2+); Universal Mobile
Telecommunications System (UMTS); LTE; Extensible Markup Language (XML) Configuration
Access Protocol (XCAP) over the Ut interface for Manipulating Supplementary Services
(3GPP TS 24.623)".
[19] IETF RFC 5322: "Internet Message Format".
[20] ISO 3166-1: "Codes for the representation of names of countries and their subdivisions - Part 1:
Country codes".
2.2 Informative references
References are either specific (identified by date of publication and/or edition number or version number) or
non-specific. For specific references, only the cited version applies. For non-specific references, the latest version of the
referenced document (including any amendments) applies.
NOTE: While any hyperlinks included in this clause were valid at the time of publication, ETSI cannot guarantee
their long term validity.
The following referenced documents are not necessary for the application of the present document but they assist the
user with regard to a particular subject area.
[i.1] ETSI TR 102 528: "Lawful Interception (LI); Interception domain Architecture for IP networks".
[i.2] ETSI TR 102 503: "Lawful Interception (LI); ASN.1 Object Identifiers in Lawful Interception and
Retained data handling Specifications".
3 Definition of terms, symbols and abbreviations
3.1 Terms
For the purposes of the present document, the terms given in ETSI TS 101 671 [1], ETSI TS 102 232-1 [2] and the
following apply:
context: logical collection of H.248 terminations
IP MultiMedia service: multimedia service that utilizes the Internet Protocol (IP) for the transport of data
MultiMedia (MM): use of computers to present text, graphics, video, animation and sound in an integrated way
MultiMedia service: communication service that offers Multimedia communication to end-users
termination: entity in H.248 that acts as a source or sink of media
NOTE: Terminations may be physical, such as a given channel on a TDM line, or ephemeral, such as an IP
endpoint.
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8 ETSI TS 102 232-5 V3.10.1 (2019-04)
TSAP identifier: piece of information used to multiplex several transport connections of the same type on a single
H.323 entity with all transport connections sharing the same Network Address (e.g. the port number in a TCP/UDP/IP
environment)
NOTE: Transport layer Service Access Point (TSAP) identifiers may be (pre)assigned statically by some
international authority or may be allocated dynamically during the setup of a call. Dynamically assigned
TSAP identifiers are of transient nature, i.e. their values are only valid for the duration of a single call.
3.2 Symbols
Void.
3.3 Abbreviations
For the purposes of the present document, the following abbreviations apply:
AF Administration Function
ASN.1 Abstract Syntax Notation One
CC IIF CC Internal Interception Function
CC Content of Communication
CCCI Content of Communication Control Interface
CCTF Content of Communication Trigger Function
CCTI Content of Communication Trigger Interface
CID Communication IDentifier
CIN Communication Identity Number
CLI Calling Line Identity
CSP Communications Service Provider
NOTE: Covers all AP/NWO/SvP.
DTMF Dual Tone Multi Frequency
GW GateWay
HI1 Handover Interface 1 (for Administrative Information)
HI2 Handover Interface 2 (for Intercept Related Information)
HI3 Handover Interface 3 (for Content of Communication)
HTTP Hyper Text Transfer Protocol
ID IDentity
IF Interception Function
IIF Internal Interception Function
IMEI International Mobile Equipment Identity
IMS IP Multimedia Subsystem
IMPI IMS Private Identity
IMPU IMS Public Identity
IMSI International Mobile Station Identity
INI Internal Network Interface
IP Internet Protocol
IRI IIF IRI Internal Interception Function
IRI Intercept Related Information
LEA Law Enforcement Agency
LEMF Law Enforcement Monitoring Facility
LI Lawful Interception
LIAF Lawful Interception Administration Function
LIID Lawful Interception IDentifier
MF Mediation Function
MG Media Gateway
MGC Media Gateway Controller
MM MultiMedia
MSRP Message Session Relay Protocol
OID Object IDentifier
PDU Protocol Data Unit
RAS Registration, Administration and Status
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RTCP RTP Control Protocol
RTP Realtime Transport Protocol
SDP Session Description Protocol
SIP Session Initiation Protocol
SSD Service-Specific Details
SvP Service Provider
TCP Transmission Control Protocol
TDM Time Division Multiplex
TSAP Transport layer Service Access Point
UDP User Datagram Protocol
UDPTL Facsimile UDP Transport Layer (protocol)
UE User Equipment
URI Uniform Resource Identifier
URL Uniform Resource Locator
XCAP eXtensible Markup Language (XML) Configuration Access Protocol
4 General
4.1 Reference Model for Lawful Interception
The present document adopts the generic reference model for the interception domain from ETSI TR 102 528 [i.1], its
internal intercept functions, Intercept Related Information Interception Function (IRI IIF), Content of Communication
Trigger Function (CCTF), and Content of Communication Internal Interception Function (CC IIF), and the Internal
Network Interfaces INI1, INI2, INI3, Content of Communication Trigger Interface (CCTI) and Content of
Communication Control Interface (CCCI) as shown in figure 1.

NWO/AP/SP DOMAIN LEA DOMAIN
HI
HI1 LEA
Administration Function (AF)
Administration
Function
INI1b INI1a
INI1c
IRI Internal Intercept
Function
INI2
(IRI IIF)
HI2
Law
Mediation
Enforcement
Function
CCTI
Monitoring
CC Trigger
(MF)
Facility
Function
(LEMF)
(CCTF)
CCCI
CC Internal Intercept
Function
HI3
INI3
(CC IIF)
Figure 1: Reference Model for Lawful Interception
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10 ETSI TS 102 232-5 V3.10.1 (2019-04)
The reference model depicts the following functions and interfaces:
• INI1a provisions Intercept Related Information Internal Interception Function (IRI IIF).
• INI1b may (statically) provision Content of Communications Trigger Function (CCTF).
• INI1c provisions the Mediation Function (MF).
• Intercept Related Information Internal Intercept Function (IRI IIF) generates IRI.
• Content of Communication Internal Interception Function (CC IIF) generates CC.
• Content of Communication Trigger Function (CCTF) controls CC IIF.
• Content of Communication Control Interface (CCCI) provisions CC IIF.
• Content of Communication Trigger Interface (CCTI) may trigger CCTF for provisioning of the CC IIF.
• Content of Communication Control Interface (CCCI) may dynamically provision the CC IIF.
• Internal interface INI1 carries provisioning information from LIAF to the Internal Intercept Functions (IIF).
• Internal interface INI2 carries Intercept Related Information (IRI) from IRI IIF to the MF.
• Internal interface INI3 carries Content of Communication (CC) information from CC IIF to the MF.
For an in-depth explanation of the functions and interface, refer to clause 4 of ETSI TR 102 528 [i.1].
4.2 Reference system model
4.2.0 Overview
The reference system model applied in the present document, as depicted in figure 2, provides a simplified model of a
technology independent, IP MultiMedia (MM) service platform, accessed by multiple different access networks. The
access networks may provide different forms of network access, using different technologies; they all have in common
that they provide IP connectivity among end-users and between end-users and the IP MM services provided by the IP
MM service platform.
Communication Signalling server
services
SvP IP Core network
GW GW GW
IP MM SvP
IAP / NWO
Access Access Access
network network network
Figure 2: Reference System Model
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11 ETSI TS 102 232-5 V3.10.1 (2019-04)
Access from the access networks into the IP Core network of the IP MM service provider is assumed to be protected by
some gateway device (e.g. a session border controller, border gateway controller or a firewall/router combination).
The IP MM Service platform contains a signalling server that provides session initiation functionality (e.g. a SIP call
manager or an H.323 gatekeeper) among end-users and between end-users and communication services (e.g. unified
messaging, audio or video conference servers).
4.2.1 Network layer Interception
Network Layer interception requires a copy of all signalling information as well as call content exchanged in the
platform to be available at a central point in the infrastructure.

Communication Signalling server

services
IRI
IIF
MF
CC
SvP IP Core network
IIF
GW GW GW
IP MM SvP
IAP / NWO
Access Access Access
network network network
Figure 3: Network layer Interception Model
This can be achieved by means of span-ports in the layer 2 switching backbone or by means of passive splitters (either
copper or fibre) at strategic points in the SvP's core network. Either way, due to the bandwidth of copied network
traffic, some form of filtering will most likely be required (e.g. by means of a layer 3 switch).
4.2.2 Service layer Interception
Service Layer interception requires LI interfaces and functionality to be available in both the signalling server and the
gateways.
Communication Signalling
IRI
services server
IIF
MF
SvP IP Core network
CC CC CC
GW  GW  GW
IP MM SvP
IIF IIF IIF
IAP / NWO
Access Access Access
network network network
Figure 4: Service layer Interception Model
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Typically the IRI IIF in the signalling server is provisioned with the target ID. At detection of a session setup for a
target, the IRI IIF will provide the IRI for the intercepted session and may provide session information to be used for
ad-hoc provisioning of the gateway devices. In some implementations, the gateway devices are also provisioned with
the target ID beforehand and are capable of detecting sessions independent from the signalling server.
4.3 General Requirements
The following requirements regarding the interception of signalling shall apply:
1) Annex B provides the functional description of the minimal set of information that is to be provided to Law
Enforcement for each intercepted communication.
2) The present document supports the interception of communication services defined in the following
IETF/ITU-T standards and recommendations:
- IETF RFC 3261 [4] (SIP);
- IETF RFC 3550 [5] (RTP);
- IETF RFC 4975 [15] (MSRP);
- Recommendation ITU-T H.323 [6];
- Recommendation ITU-T H.225.0 [12];
- Recommendation ITU-T H.245 [13];
- Recommendation ITU-T T.38 [16].
3) Any deviation from the supported IETF and ITU-T specifications identified in item 2, e.g. vendor specific
parameters, shall be agreed in advance between the Communications Service Provider (CSP) and Law
Enforcement Agency (LEA).
4) The present document specifies the handover of intercepted signalling containing all information required in
ETSI TS 101 331 [10] by encapsulating that intercepted signalling.
5) IRI that is not part of intercepted signalling shall also be delivered. The format of such information on the
handover interface shall be agreed in advance between the CSP and LEA.
6) As a national option, mapping of the IRI information onto specific messages at the handover interface may be
mandated, e.g. according to the ATIS-PP-1000678 [11] specification.
5 Interception of IP Multimedia services
5.1 Identification of target of interception
5.1.1 SIP Target Identification
The target identity is not a network layer or transport layer address. The target identity shall be a public or private
address type that uniquely identifies the target in the CSP's network and by means of which sessions among users can
be established, such as:
• TEL URI;
• SIP URI;
• E.164 Number.
NOTE: IMPU and IMPI are examples of public/private identifiers.
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5.1.2 H.323 Target Identification
The target identity is not a network layer or transport layer address. The target identity shall be an address type that
uniquely identifies the target in the CSP's network and by means of which sessions among users can be established,
such as:
• H.323 URL;
• H.323 ID;
• E.164 Number.
5.1.3 Other Target Identifiers
Depending on the CSP network configuration and technical/mapping capabilities, other target identifiers might be used.
This includes access network identifiers such as IMEI or IMSI.
5.2 Interception of signalling
5.2.1 Provisioning of the SIP IRI IIF
SIP messaging IETF RFC 3261 [4] is reported as Intercept Related Information (IRI) for the interception of multi-media
service. All SIP messages executed on behalf of a target subscriber are subject to interception at the IRI Internal
Interception Function (IIF). Based upon network configuration, the Administration Function (AF) shall provision IRI
IIF with SIP Uniform Resource Identifier (URI) or TEL Uniform Resource Locator (URL) target identifiers. These
resulting intercepted SIP messages shall be sent to the Mediation Function (MF) over the INI2 interface for mediation
prior to transmittal across the HI2 interface.
5.2.2 Provisioning of the H.323 IRI IIF
H.323 call signalling, call control and subscriber controlled input messages are reported as Intercepted Related
Information (IRI) for the interception of multi-media services. H.323 call signalling and control messages refer to the
basic call signalling (H.225.0), call control (H.245) and those messages required for the signalling of supplementary
services (i.e. H.450.x). Subscriber controlled input messages refer to those messages generated as a result of user
procedures for the control of Supplementary Services (activation/deactivation/interrogation).
All H.323 call signalling, call control and subscriber controlled input messages that are transmitted on behalf of the
target subscriber are subject to intercept at the IRI IIF. Based upon the network configuration, the AF shall provision
IRI IIF with either a H.323 Unique Resource Locator (H.323-URL), or a H.323 Identity (H.323-ID), or a public E.164
telephone number.
If available events related to the Registration, Administration and Status (i.e. H.323 RAS) of the target subscriber's
terminal equipment are also subject to intercept at the IRI IIF.
5.2.3 Location information
The IRI Internal Interception Function (IIF) may report location information to satisfy the requirement in clause B.3.
The availability and format of location information in the IRI IIF may depend on the network access technology. The
present document uses the common parameter from ETSI TS 102 232-1 [2] to signal this information. Use of this
parameter is subject to national agreement.
5.2.4 Supplementary Services
A target subscriber may make use of supplementary services offered by the IP MultiMedia platform. Typical
supplementary services are the maintenance of presence information and the manipulation of call forwarding and barred
numbers.
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The IP MultiMedia platform may offer an IETF RFC 4825 [17] XCAP interface, which can be used by the target's UE
to modify supplementary services settings. A common interface making use of XCAP is the 3GPP Ut interface as
described in ETSI TS 124 623 [18].
Intercepted XCAP messages that are sent or received on behalf of the target subscriber will be handed over as IRI using
the XCAPMessage ASN.1 structure. The XCAPMessage structure contains the complete HTTP application layer
contents (including all headers), without any underlying TCP/IP protocol messages.
5.2.5 Additional signalling information
The IRI Internal Interception Function (IIF) may report additional signalling information without affecting the
intercepted signalling messages. The additional signalling information could be provided by the network via different
means than the information contained in the intercepted signalling messages.
The present document supports the handover of additional information, separately to any intercepted signalling
messages, using SIP header format as defined in IETF RFC 3261 [4] and IETF RFC 5322 [19]. These SIP headers shall
be formatted per the requirements as stated in other specifications, such as an IETF RFC or a 3GPP TS. National
agreement may define which specifications apply.
5.3 Assigning a value to the Communication Identity Number
5.3.0 Introduction
In order to produce useful IRI records from events, the IRI and CC records of a communication session shall be
correlated with a single value for the Communication Identity Number (CIN) field. The CIN should be assigned upon
first IRI or CC message.
5.3.1 Assigning a CIN value to SIP related IRI
All IRI events resulting from SIP messages in a single call will be assigned the same value for the CIN. A call may
consist of two or more call signalling legs (e.g. when communicating via a SIP proxy). The various related call
signalling legs are correlated. Implementation of SIP leg correlation is out of scope for the present document, a possible
option is to use the P-Charging-Vector header (see ETSI TS 133 108 [9], Annex F) if present.
5.3.2 Assigning a CIN value to H.323 related IRI
All IRI events resulting from messages within a single H.323 call will be assigned the same value for the CIN.
Messages within a H.323 call can be identified as those messages containing, or associated with the same unique
H.225.0 Call ID. The term H.323 Call is defined in the Recommendation ITU-T H.323 [6]. The term Call ID also
referred to as H.225.0 Call ID is described in the Recommendations ITU-Ts H.323 [6] and H.225.0 [12].
5.4 Events and IRI record types
The following requirements need to be met:
• All multimedia signalling and control messages to or from a targeted subscriber and all multimedia signalling
and control messages executed on behalf of or related to a targeted subscriber are intercepted by the IRI IIF
and sent to the MF over the INI2 interface as IRI records.
• IRI records for all events related to a single communication session, which may consist of multiple media
streams, that are being exchanged among the possibly more than two users, will be assigned the same CIN
value.
• In addition, information on non-transmission related actions of a target constitute IRI is assigned CIN and is
sent via HI2 (e.g. information on subscriber controlled input).
NOTE: This includes events related to the target service handled internally by network functions
(e.g. communications among GWs, Signalling Servers and Communication Services). The format of such
information on the handover interface should be agreed in advance between the CSP and LEA.
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15 ETSI TS 102 232-5 V3.10.1 (2019-04)
For each event, a record is sent to the LEMF. A new value for the CIN field is assigned if an event is detected that is not
related to an already existing communication session. This event is reported as an IRI-REPORT or IRI-BEGIN record.
Every subsequent record related to this communication session is reported as an IRI-REPORT or IRI-CONTINUE
record. At the detection of the event that denotes the end of a session an IRI-REPORT or IRI-END record is sent.
In case of implementation issues, operational flaws or problems, events may need to be reported for a communication
session for which the IRI-END record has already been sent. These events are reported as an IRI-REPORT with the
proper value for the CIN.
Table 1 summarizes the mapping between event type and record type sent to the LEMF.
Table 1: Mapping between IP MM Events and HI2 Records Type
Event IRI Record Type
At assignment of a new CIN value BEGIN/REPORT
All intermediate signalling, other than the last event CONTINUE/REPORT
The last event related to a communication session END/REPORT
Delayed IRI events related to an already ended session REPORT
Events that are not mapped REPORT
NOTE: Not mapped events could for example be encapsulated SIP messages.

5.5 Interception of Content of Communication
The Content of Communication (CC) provided is a copy of the multimedia stream sent through the SvP's network that
is addressed to, sent from or related to the targeted subscriber as described in the intercepted call signalling and call
control information.
Multimedia stream consists of:
• every IETF RFC 3550 [5] RTP and RTCP packet for real time multimedia services (e.g. VoIP);
• every IETF RFC 4975 [15] MSRP packet for MSRP based multimedia services (e.g. instant messaging, file
sharing, etc.);
• every Recommendation ITU-T T.38 [16] UDPTL packet for Facsimile multimedia service.
The RTP CC shall also contain the RTP header, UDP header and IP header, except by agreement between CSP and
LEA (for example these headers may not be available at the point of interception). Each IPMMCC PDU shall contain
one intercepted packet.
The UDPTL CC shall follow the same principles.
The MSRP CC shall contain the TCP header. If the TCP header of the MSRP CC payload is not available, the
frameType msrpFrame may be used.
The frameType field indicates which headers are present in a given CC stream.
In the case where the RTP header is unavailable, one may be inserted by the mediation function, subject to agreement
between LEA and CSP. The addition of an inserted RTP header may aid processing the audio stream at the receiver.
When an artificial header is used, this shall be signalled using the artificialRtpFrame parameter of the FrameType
structure.
IP and UDP or TCP headers shall not be inserted into the intercepted material by the mediation function if they are
unavailable.
In addition to IRI messages, all RTP/RTCP, UDPTL or MSRP packets identified to be associated with a specific
intercepted call or session shall be assigned the same CIN.
In case where some headers are not reported within the CC (because not available at the point of interception) there may
be a need to identify the media streams inside the CC, typically in situations where the SIP communication consists of
multiple media streams of same type. The streamIdentifier field identifies the media stream unambiguously (it may
contain the corresponding SDP 'c=' and 'm=' lines for instance).
ETSI
16 ETSI TS 102 232-5 V3.10.1 (2019-04)
NOTE 1: The ASN.1 definition for CC is presented as the iPMultimediaPDU in clause 7.
NOTE 2: The CC also contains the target media streams that are not transferred via RTP or RTCP or UDPTL or
MSRP (for example, those streams handled by a GW and not passing the core network). The format of
such information on the handover interface should be agreed in advance between the CSP and LEA.
5.6 Direction for IMS IRI for Signalling Messages
In order to indicate the direction of a signalling message carried in the IRI payload, the payloadDirection parameter (as
defined in ETSI TS 102 232-1 [2]) parameter may be used. Use of this parameter is subject to national agreement. If the
payloadDirection parameter is used then it shall be populated as follows:
• if the signalling message was sent from the target, the fromTarget value shall be used;
• if the signalling message was sent to the target, the toTarget value shall be used;
• if the direction could not be determined reliably, the indeterminate value shall be used.
The values combined and notapplicable shall not be used unless by specific national agreement.
5.7 Direction for IMS sessions
5.7.1 Direction for SIP sessions
In order to indicate the direction of a SIP session, the sessionDirection parameter (as defined in ETSI TS 102 232-1 [2])
may be used. Use of this parameter is subject to national agreement. If the sessionDirection parameter is used for SIP
sessions then it shall be populated as follows:
• if the SIP message which results in the CIN for the session being allocated is sent to the target, the toTarget
value shall be used;
• if the SIP message which results in the CIN for the session being allocated is sent from the target, the
fromTarget value shall be used;
• if the SIP message which results in the CIN for the session being allocated is sent from and to the target, the
combined value shall be used;
• if the direction could not be determined reliably, the indeterminate value shall be used.
The value notapplicable shall not be used unless by specific national agreement.
5.7.2 Direction for H.323 sessions
The indication of the direction for H.323 sessions is not considered in the present document.
6 Handover Interface
6.1 Intercepted Related Information
The Communication Identity Number (CIN) is used to uniquely identify a communication session (as described in ETSI
TS 102 232-1 [2] and ETSI TS 101 671 [1]). Applied to IP MM Services, a communication session refers to a single
self contained transaction or a series of protocol data units that together form a self-contained communication such as a
SIP or H.323 Session.
ETSI
17 ETSI TS 102 232-5 V3.10.1 (2019-04)
6.2 Correlation of IRI and CC
To assure correlation between the independently transmitted Content of Communication and the Intercepted Related
Information (IRI) of an intercepted call the following parameters are used:
• Lawful Interception Identifier (LIID);
• Communication Identifier (CID).
NOTE: The target identifier may not necessarily be found in both communication content and interception related
information.
In situations where the SIP communication consists of multiple media streams the streamIdentifier field of CC may be
used to correlate each media stream of CC with the corresponding SDP media description of IRI.
7 ASN.1 specification for IRI and CC
The ASN.1 (Recommendation ITU-T X.680 [3]) module that represents the information in the present document and
meets all stated requirements is shown below. ETSI TR 102 503 [i.2] gives an overview of the relevant Object
IDentifiers (OID) used in ASN.1 modules of the Lawful Intercept specifications and points to the specification where
the modules can be found.
The ASN.1 definition is in file "IPMultimedia
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