ETSI TS 103 221-2 V1.5.2 (2021-10)

Lawful Interception (LI); Internal Network Interfaces; Part 2: X2/X3

RTS/LI-00213-2

General Information

• Status: Not Published
• Technical Committee: LI - Lawful Interception
• Current Stage: 12 - Completion
• Due Date: 09-Nov-2021
• Completion Date: 15-Oct-2021

Standards Content (Sample)

ETSI TS 103 221-2 V1.5.2 (2021-10)






TECHNICAL SPECIFICATION
Lawful Interception (LI);
Internal Network Interfaces;
Part 2: X2/X3

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2 ETSI TS 103 221-2 V1.5.2 (2021-10)

Reference
RTS/LI-00213-2
Keywords
interface, lawful interception
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ETSI

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3 ETSI TS 103 221-2 V1.5.2 (2021-10)
Contents
Intellectual Property Rights . 6
Foreword . 6
Modal verbs terminology . 6
1 Scope . 7
2 References . 7
2.1 Normative references . 7
2.2 Informative references . 8
3 Definition of terms, symbols and abbreviations . 8
3.1 Terms . 8
3.2 Symbols . 9
3.3 Abbreviations . 9
4 Introduction and reference model . 9
4.1 Reference model . 9
4.2 Assumptions . 10
4.2.1 Architecture . 10
4.2.2 Implementation/realization . 10
4.2.3 Deployment infrastructure . 11
4.2.4 Regulatory assumptions . 11
4.3 Relationship to other standards . 11
5 Message contents and parameters . 12
5.1 Overview . 12
5.2 PDU Header Fields . 12
5.2.1 Version . 12
5.2.2 PDU Type . 13
5.2.3 Header Length . 13
5.2.4 Payload Length . 13
5.2.5 Payload Format . 13
5.2.6 Payload Direction . 13
5.2.7 XID . 14
5.2.8 Correlation ID . 14
5.3 Conditional Attribute Fields . 14
5.3.1 General structure . 14
5.3.2 ETSI TS 102 232-1 Defined Attribute . 15
5.3.3 3GPP TS 33.128 Defined Attribute . 15
5.3.4 3GPP TS 33.108 Defined Attribute . 15
5.3.5 Proprietary Attribute . 15
5.3.6 Domain ID (DID) . 16
5.3.7 Network Function ID (NFID) . 16
5.3.8 Interception Point ID (IPID) . 16
5.3.9 Sequence Number . 16
5.3.10 Timestamp . 16
5.3.11 Source IPv4 Address . 16
5.3.12 Destination IPv4 Address . 16
5.3.13 Source IPv6 Address . 17
5.3.14 Destination IPv6 Address . 17
5.3.15 Source Port. 17
5.3.16 Destination Port . 17
5.3.17 IP Protocol . 17
5.3.18 Matched Target Identifier . 17
5.3.19 Other Target Identifier . 17
5.3.20 MIME Content Type . 17
5.3.21 MIME Content Transfer Encoding . 18
5.3.22 Additional XID Related Information . 18
5.4 Payload . 18
ETSI

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4 ETSI TS 103 221-2 V1.5.2 (2021-10)
5.4.1 Overview . 18
5.4.2 ETSI TS 102 232-1 Defined Payload . 19
5.4.3 3GPP TS 33.128 Defined Payload . 19
5.4.4 3GPP TS 33.108 Defined Payload . 19
5.4.5 Proprietary Payload. 19
5.4.6 IPv4 Packet . 19
5.4.7 IPv6 Packet . 19
5.4.8 Ethernet Frame . 19
5.4.9 RTP Packet . 19
5.4.10 SIP Message. 19
5.4.11 DHCP Message . 20
5.4.12 RADIUS Packet . 20
5.4.13 GTP-U Message . 20
5.4.14 MSRP Message . 20
5.4.15 3GPP TS 33.108 EpsIRIContent. 20
5.4.16 MIME Message . 20
5.4.17 3GPP Unstructured PDU . 20
6 Transport . 20
6.1 Summary . 20
6.2 TLS Transport Profile . 21
6.2.1 General . 21
6.2.2 Profile . 21
6.2.3 Authentication . 21
6.2.4 Keepalive mechanism for reliability . 21
Annex A (normative): Requirements . 22
A.1 X2 Protocol & Architecture requirements . 22
A.1.1 Basic Functionality . 22
A.1.2 Flexible . 22
A.1.3 Extensible . 22
A.1.4 Lightweight . 22
A.1.5 Delay . 22
A.1.6 Permanent and Dynamic Connections . 22
A.1.7 Reliability . 22
A.1.8 Error detection . 22
A.1.9 Redundancy . 22
A.1.10 Correlation . 23
A.1.11 Mediation into HI2/HI3 . 23
A.2 X2 Security requirements . 23
A.2.1 Authentication and Authorization . 23
A.2.2 Accounting and Audit . 23
A.2.3 Integrity Protection . 23
A.2.4 Confidentiality Protection . 23
A.2.5 Replay Protection . 23
A.2.6 Standalone interface . 23
A.2.7 Minimum Security Level . 23
A.2.8 Underlying Infrastructure Trust . 23
A.2.9 Firewall and NAT Transversal . 24
A.2.10 Certificate and Key Management . 24
A.3 X3 Protocol & Architecture requirements . 24
A.3.1 Basic Functionality . 24
A.3.2 Flexible . 24
A.3.3 Extensible . 24
A.3.4 Lightweight . 24
A.3.5 Delay . 24
A.3.6 Permanent and Dynamic Connections . 24
A.3.7 Reliability . 24
A.3.8 Error detection . 24
A.3.9 Redundancy . 25
ETSI

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5 ETSI TS 103 221-2 V1.5.2 (2021-10)
A.3.10 Correlation . 25
A.3.11 Mediation into HI2/HI3 . 25
A.4 X3 Security requirements . 25
A.4.1 Authentication & Authorization . 25
A.4.2 Accounting/Audit . 25
A.4.3 Integrity Protection . 25
A.4.4 Confidentiality Protection . 25
A.4.5 Replay Protection . 25
A.4.6 Standalone interface . 25
A.4.7 Minimum Security Level . 26
A.4.8 Underlying Infrastructure Trust . 26
A.4.9 Firewall and NAT Transversal . 26
A.4.10 Certificate and Key Management . 26
Annex B (informative): Illustrative deployment scenarios . 27
B.1 Introduction . 27
B.2 Simple deployment scenario . 27
B.3 Individual X3 POIs with shared X2 POI . 27
B.4 Separated interfaces . 28
Annex C (informative): Change History . 29
History . 30


ETSI

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6 ETSI TS 103 221-2 V1.5.2 (2021-10)
Intellectual Property Rights
Essential patents
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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 Directives including the ETSI IPR Policy, no investigation regarding the essentiality of IPRs,
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.
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Foreword
This Technical Specification (TS) has been produced by ETSI Technical Committee Lawful Interception (LI).
The present document is part 2 of a multi-part deliverable. Full details of the entire series can be found in part 1 [1].
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.

ETSI

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7 ETSI TS 103 221-2 V1.5.2 (2021-10)
1 Scope
The present document defines an electronic interface for the transmission of intercepted information as part of Lawful
Interception. This interface is used from points of interception to LI mediation functions.
Typical reference models for LI define an interface between Law Enforcement Agencies (LEAs) and Communication
Service Providers (CSPs), called the handover interface. They also define an internal network interface within the CSP
domain between administration/mediation functions for lawful interception and network internal functions, which
facilitates the interception of communication. This internal network interface typically consists of three sub-interfaces;
administration (called X1), transmission of intercept related information (X2) and transmission of content of
communication (X3). The present document specifies a protocol for delivering X2 and X3.
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 103 221-1: "Lawful Interception (LI); Internal Network Interfaces; Part 1: X1".
[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] IEEE Std 1003.1™-2017: "IEEE Standard for Information Technology - Portable Operating
System Interface (POSIX™) Base Specifications, Issue 7".
[4] IETF RFC 791: "Internet Protocol".
[5] IETF RFC 8200: "In
...