MAP vs CAP
MAP (Mobile Application Part) and CAP (CAMEL Application Part) both ride on top of TCAP over SCCP. MAP handles mobility, authentication, and SMS; CAP handles intelligent-network service triggers (prepaid, VPN, custom routing).
| Attribute | MAP | CAP |
|---|---|---|
| Purpose | Mobility, auth, SMS, LI | Prepaid / IN service triggers |
| Typical operations | UpdateLocation, SRI-SM, AnyTimeInterrogation | InitialDP, ApplyCharging, Connect |
| Standard | 3GPP TS 29.002 | 3GPP TS 29.078 |
| Attack profile | Location tracking, SMS interception | Fraudulent routing, charging bypass |
| Firewall category | FS.11 Cat 1/2/3 | FS.11 CAMEL screening |
Verdict
Most SS7 firewall RFPs focus on MAP and forget CAP. That is how prepaid fraud and IN-triggered call-routing abuse slip through — the CAP surface is smaller but higher-value per successful call.