Outage category: VoIP phone service
Location: All US Mason campuses using the Vonage phone service - Those using AT&T to dial the Vonage phone line
Status: Closed
Resolved Alert:
Initial Symptoms
Calls could not be received from AT&T callers
Root Cause Analysis
Cause
A signaling configuration from the originating provider introduced an unexpected parameter into inbound call requests. This parameter affected call routing logic and led to intermittent failures.
Resolution
A system-wide rule was implemented to strip the unnecessary parameter from inbound signaling across all session border controllers, ensuring correct call routing.
Prevention
Develop a comprehensive independent test plan which covers all critical scenarios.
Procedural improvement implemented.