Carrier

A carrier (also called a VoIP provider or ITSP) is a telecommunications company that provides the connection between VICIdial and the public telephone network (PSTN). Carriers provision SIP trunks for outbound calling capacity and supply DIDs (phone numbers) for inbound call reception, charging per-minute or per-channel rates for the service.

How It Works in VICIdial

VICIdial connects to carriers through SIP or PJSIP trunk configurations. Each carrier provides connection parameters — SIP server address, authentication credentials, and provisioned channel counts. VICIdial’s Asterisk server registers with the carrier (or receives connections from it) and routes calls according to the campaign’s dial prefix configuration.

Most VICIdial deployments use multiple carriers for redundancy and cost optimization. The dialplan can route calls through different carriers based on destination area code, time of day, or primary/failover priority. Some carriers specialize in outbound high-volume calling and offer features like STIR/SHAKEN attestation, CNAM registration, and CID management.

Carriers also implement their own robocall mitigation programs and may block or flag calls from VICIdial systems that generate excessive short-duration calls or high complaint rates.

Why It Matters

Carrier selection and management are critical to outbound campaign performance. The carrier determines answer rates (through their network reputation and STIR/SHAKEN attestation level), call quality (through their network infrastructure), and cost structure (per-minute rates and monthly minimums).

Using carriers with full STIR/SHAKEN attestation (A-level) significantly improves answer rates in post-STIR/SHAKEN environments. Diversifying across multiple carriers provides failover protection and prevents single-point-of-failure scenarios. See the DID hygiene feature page for carrier management strategies.