MTSI (Multimedia Telephony Service for IMS)

MTSI in context

The radio access network is the layer where mobile devices attach to the operator's infrastructure. Attacks in this layer include IMSI catching, rogue base stations, downgrade attacks and jamming, and defenses hinge on mutual authentication, integrity-protected signaling and Open RAN supply-chain hygiene.

Signaling protocols carry the control-plane instructions that set up calls, register subscribers, hand over sessions and route SMS. SS7, Diameter, GTP-C and SIP are the four dominant families, and interconnect exposure of any of them is treated by GSMA FS.11 / FS.19 / FS.20 as a top-tier telecom risk.

To place MTSI in the wider telecom-security picture, review mTLS, NRF, RTP, Denial of Service (DoS), IBCF and Media Gateway.

Related terms

• mTLS
• NRF
• RTP
• Denial of Service (DoS)
• IBCF
• Media Gateway
• MPLS
• MVNO

Equipment

IMS core (CSCF, TAS, MRF, MGCF, BGCF)

• BGCF
• CSCF
• E-CSCF
• I-CSCF
• IMS
• IMS-AKA
• IR.92
• IR.94
• MGCF
• P-CSCF
• All 14 terms

Articles in the P1 mobile network security guide

Related topic hubs

• VoLTE Security IMS/VoLTE signaling risk: SIP, IMS-AKA, media plane attacks.
• IMS Security Training Training on IMS, VoLTE/VoNR, SIP and RCS security.
• Diameter Security 4G/LTE Diameter threats across IPX/roaming and DEA defenses.
• Diameter Attacks S6a IDR/PUR/CLR abuse, subscriber tracking, LTE signaling attacks.

More from the TelcoSec Glossary

Browse the full TelcoSec Glossary, the Ultimate Guide to Mobile Network Security, or the P1 Arsenal of telecom-security tools.