ETSI TS 103 221 (Internal Network Interfaces for Lawful Interception)

Also known as: X1 interface, X2 interface, X3 interface

ETSI TS 103 221 is the ETSI standard defining internal handover interfaces for lawful interception within an operator's network. Part 1 (X1) covers provisioning and activation of intercept targets between the LI administration function and network functions; Part 2 (X2/X3) covers the delivery of intercept-related information and content of communication to the mediation function. Widely adopted in 5G LI architectures.

Categories: Threats and AttacksProtocols and StandardsRegulation and Compliance

ETSI TS 103 221 in context

Telecom threats range from opportunistic SMS phishing and SIM swap to nation-state grade location tracking and lawful-interception abuse. The common thread is that most attacks exploit the inherited trust model of legacy signaling. SS7 and Diameter were designed for a closed operator community that no longer exists.

Telecom security is written into standards from 3GPP, GSMA, ETSI, IETF and ITU-T. Understanding which body owns which specification, and how the specs interlock (for example 3GPP TS 33.501 with GSMA FS.34 for 5G SBA security), is essential for both design and audit work.

To place ETSI TS 103 221 in the wider telecom-security picture, review X2 (LI), X3 (LI), Mediation Device (Lawful Interception), X1, IRI and HI1.

Related terms

Equipment

Lawful interception systems (ADMF, mediation, HI1/2/3)

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