How It Works
Plivo maintains multiple carrier routes for every destination. When you place an outbound call, Plivo monitors the call route in real time. If the primary carrier fails or degrades, Plivo reroutes the call through an alternate carrier instantly.| Scenario | What happens |
|---|---|
| Carrier outage | Primary carrier is down or unreachable — calls reroute through an alternate carrier. |
| Network congestion | High call volume causes drops on the primary route — calls shift to a less congested carrier. |
| Route quality degradation | Call quality drops below acceptable thresholds — calls switch to a higher-quality route. |
India — Additional Setup Required
For most countries, Plivo handles carrier failover entirely behind the scenes. India is different. Indian telecom regulations tie phone numbers to specific carriers. Plivo cannot silently reroute calls through a different carrier’s number without explicit provisioning. To get failover coverage for India numbers, you need to set up High Availability (HA) numbers.What Are HA Numbers?
High Availability pairs your primary India number with a backup number from a different carrier. If the primary number or its carrier becomes unreachable, calls automatically reroute through the fallback number — no code changes needed in your application.- You enable HA on an India local number (new or existing).
- Plivo provisions a second number from a different carrier and adds it as an active rental on your account.
- Plivo monitors the primary number in real time. If a failure or congestion is detected, calls reroute through the fallback number automatically.
Enable HA When Buying a New Number
- Go to Phone Numbers > Buy Number in the Plivo console.
- Search for an India local number.
- On the Details page, scroll to High Availability.
- Check Enable high availability backup number.
- Complete the purchase — Plivo provisions a fallback number and bills it automatically.
Enable HA on an Existing Number
- Go to Phone Numbers > Active Numbers in the Plivo console.
- Click the number you want to upgrade.
- Scroll to the High Availability section.
- Check Enable high availability backup number and click Save.
- The Fallback Number appears in your number details once provisioned.
Billing
Enabling HA rents a second number from a different carrier. This fallback number is added as a separate active rental on your Plivo account and billed at the standard monthly rate for India local numbers — in addition to your primary number. The fallback number is visible under Phone Numbers > Active Numbers alongside your other rentals.Frequently Asked Questions
Do I need to change my application code?
No. Carrier failover is automatic and transparent. Your application continues to use the same Plivo APIs and number configuration without any changes. For India HA numbers, failover is also automatic once you enable it — no code changes required.How can I see which fallback number is assigned to my India number?
Go to Phone Numbers > Active Numbers in the Plivo console and click on the primary number. The Fallback Number field shows the assigned backup number.Does carrier failover cover incoming calls?
Carrier failover applies to outbound calls. Incoming call behavior follows your standard number configuration.Do I need HA numbers outside India?
No. Plivo handles carrier failover automatically for all countries other than India. HA numbers are only needed for India due to regulatory requirements that tie numbers to specific carriers.Related
- India Calling Regulations — Regulatory requirements for voice calling in India
- India Number KYC — KYC and number rental process for India
- Phone Numbers — Overview of number types
- Account Phone Numbers — Manage your active numbers