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PASSEDvoip / sbc_failure
Session Border Controller Failure — All SIP Trunks Down
The primary SBC (Session Border Controller) suffers a hardware failure, dropping all active calls and preventing new call setup. The standby SBC fails to take over because the HA license expired. All inbound and outbound PSTN calls are completely offline.
Pattern
VOIP_QUALITY
Severity
CRITICAL
Confidence
95%
Remediation
Remote Hands
Test Results
| Metric | Expected | Actual | Result |
|---|---|---|---|
| Pattern Recognition | VOIP_QUALITY | VOIP_QUALITY | |
| Severity Assessment | CRITICAL | CRITICAL | |
| Incident Correlation | Yes | 34 linked | |
| Cascade Escalation | Yes | Yes | |
| Remediation | — | Remote Hands — Corax contacts on-site support via call, email, or API |
Scenario Conditions
AudioCodes Mediant 4000 primary SBC. Standby SBC HA license expired 2 weeks ago. Primary SBC hardware failure (memory module). All SIP trunks terminated on primary. 300 concurrent calls dropped. No automatic failover.
Injected Error Messages (3)
Primary SBC hardware failure — sbc-01 unreachable, memory module failure detected via IPMI, all SIP trunks down, 300 active calls dropped, sip registration to ITSP lost, no PSTN connectivity, PBX reporting trunk unregistered
Standby SBC failover failed — sbc-02 HA license expired, automatic failover blocked, sip registration takeover not attempted, standby showing 'HA License Invalid' alarm, manual SIP trunk reconfiguration required
PBX all SIP trunks unregistered — sip registration to primary SBC failed (unreachable), sip registration to standby SBC rejected (not in active mode), all PSTN call routing offline, 500 users without external calling, IVR and auto-attendant unreachable from outside
Neural Engine Root Cause Analysis
The primary SBC (Session Border Controller) sbc-01 has experienced a hardware failure specifically affecting its memory modules, as confirmed via IPMI monitoring. This hardware failure has rendered the entire SBC unreachable, causing complete loss of PSTN connectivity, dropped all 300 active calls, and prevented SIP trunk registration with the ITSP. The 14 correlated incidents within the same timeframe likely represent cascading failures of dependent VoIP services that rely on this primary SBC for connectivity.
Remediation Plan
1. Immediately failover to secondary SBC if available to restore PSTN connectivity 2. Contact hardware vendor for emergency memory module replacement on sbc-01 3. Monitor secondary SBC capacity and performance during failover period 4. Once hardware is repaired, perform staged failback testing 5. Implement redundancy monitoring to prevent single points of failure 6. Review SBC clustering configuration to ensure proper high availability
Tested: 2026-03-30Monitors: 3 | Incidents: 3Test ID: cmncjscjw048vobqe7dpsun36