Mobile / Local Number Portability

Also known as: MNP, LNP, Mobile Number Portability

Number portability is the regulatory capability that lets subscribers keep their phone number when changing operator. Networks resolve ported numbers via a national portability database or All Call Query, and the routing information is carried in SS7 (Release-to-Pivot, IN triggers) or in Diameter/SIP for LTE/VoLTE. From a security perspective, portability requests are a high-value target for SIM-swap-like account takeover and require strong subscriber authentication.

Categories: SignalingIdentity and Subscriber

Number Portability in context

Signaling protocols carry the control-plane messages that set up calls, register subscribers 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 as top-tier telecom risk.

Subscriber identifiers (IMSI, SUPI, MSISDN, IMEI) anchor authentication, charging and lawful interception. Any protocol that leaks a permanent identifier is treated as a privacy defect, which is why 5G introduced SUCI concealment on the air interface.

To place Number Portability in the wider telecom-security picture, review Roaming, SRI, Cleartext (Plain Text), E.164, SMS and SS7: each entry cross-references back to this page so you can walk the topic in either direction.

Related terms

Related topic hubs

  • Signaling Firewall Unified SS7/Diameter/GTP/SMS signaling firewall framework.
  • SS7 Security SS7/MAP/CAP/SCCP attacks and defenses across 2G/3G interconnect.
  • 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.