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 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.

OSS/BSS platforms (provisioning, charging, mediation, order management) hold the highest-value subscriber and revenue data on the operator side. They are heavily targeted for fraud and insider abuse and are increasingly in scope for regulatory obligations like NIS2 and the UK Telecoms Security Act.

To place MDF3 in the wider telecom-security picture, review MDF2, MAC Address, X3 (LI), ETSI TS 103 221, PCF and CC (LI).

Related terms

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