CAP (CAMEL Application Part)

CAMEL Application Part is the SS7 protocol that lets a service control point trigger and influence calls in real time, enabling prepaid charging, virtual private networks, and other intelligent network services in 2G and 3G. CAP runs on top of TCAP and is functionally similar to INAP. Because it can authorise or extend calls, malicious or misconfigured CAP messages can enable revenue leakage and toll fraud, so CAP traffic is filtered alongside MAP at the SS7 firewall.

Categories: SignalingIdentity and SubscriberSecurity Controls

CAP 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 CAP in the wider telecom-security picture, review AAA, Any-Time Interrogation (ATI), IMSI, STIR, RCS and 1G — each entry cross-references back to this page so you can walk the topic in either direction.

Related terms

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