MDF3 (Mediation and Delivery Function 3 (CC))

Also known as: Mediation Delivery Function 3

MDF3 is the 3GPP lawful-interception function (TS 33.126, TS 33.127, TS 33.128) that mediates Content of Communication from POIs and delivers it to the LEA over the LI_HI3 interface, correlated with MDF2's IRI stream. It handles high-bandwidth media and user-plane payloads and is deployed inside the operator's segregated LI domain.

Categories: Protocols and StandardsOperations and Business

MDF3 in context

Telecom security is written into standards from 3GPP, GSMA, ETSI, IETF and ITU-T. Understanding which body owns which specification, and how they interlock, is essential for both design and audit work.

OSS/BSS platforms hold the highest-value subscriber and revenue data on the operator side, are heavily targeted for fraud and insider abuse, and are in scope for NIS2 and the UK Telecoms Security Act.

To place MDF3 in the wider telecom-security picture, review 3GPP, Charging System, eSIM (Embedded SIM, eUICC), IP, MAC Address and Patch — each entry cross-references back to this page so you can walk the topic in either direction.

Related terms

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