Failover¶
Document Metadata
Category: Carrier Management / Fail-over & Redundancy Configuration
Audience: Administrators, Engineers, Support Team
Difficulty: Intermediate to Advanced
Time Required: Approximately 1–2 hours
Prerequisites: Active ConnexCS account with Carrier-module access; understanding of SIP routing, carrier fail-over strategies, and rate-card sequencing
Related Topics: Carrier Main Configuration, Reply Management
Next Steps: Define fail-over settings for carriers (including alternative IPs or backup carriers), configure sequential fail-over logic per SIP response codes, test fail-over via real-call scenarios, and monitor using fail-over logs
Management Carrier Failover
Overview¶
The Failover tab lists calls that failed with one carrier but were successfully connected through another carrier.
This helps you:
- Troubleshoot carrier routing issues.
- Identify carriers with poor performance or routing failures.
- Detect potential False Answer Supervision (FAS) billing fraud.
False Answer Supervision (FAS)¶
What is FAS?¶
False Answer Supervision (FAS) is a fraudulent practice in which a carrier falsely indicates that a call has been successfully connected while routing it to an unintended destination, such as a recorded announcement, radio station, or a low-cost number.
As a result:
- The caller is charged for the call.
- The intended recipient is never reached.
- The fraudulent carrier avoids paying the proper termination charges.
How FAS Affects Failover Reporting¶
Calls appearing in the Failover report may indicate potential FAS activity.
For example:
- Carrier A falsely reports the call as answered.
- ConnexCS detects the unsuccessful call attempt and routes the call through another carrier.
- The call successfully connects via the alternate carrier, while the failed attempt remains visible in the Failover report for investigation.
SIP Response Codes That Do Not Trigger Failover¶
ConnexCS halts routing and does not perform failover for the following SIP response codes:
| SIP Code | Description |
|---|---|
| 3XX | Redirection responses (rewritten internally to 503 Service Unavailable) |
| 404 | Not Found |
| 480 | Temporarily Unavailable |
| 486 | Busy Here |
| 6XX | Global Failure responses (for example: 600 Busy Everywhere, 603 Decline, 604 Does Not Exist Anywhere, 606 Not Acceptable) |