SIP Trunk Service

Manage SIP trunks for enterprise voice communications. Create trunks with automatic SIP domain provisioning, configure authentication methods, and set up outbound routing for scalable telephony infrastructure.

What is a SIP Trunk?

A SIP trunk is a virtual connection that enables voice communication over IP networks. Each trunk serves as a dedicated voice gateway with its own authentication, rate limits, and routing configuration. Vobiz automatically provisions each trunk with a unique SIP domain and integrates it with Kamailio for robust SIP routing and authentication.

  • Auto-generated SIP domains: Each trunk gets a unique domain like trunkId.sip.vobiz.ai
  • Flexible authentication: Support for both username/password and IP-based authentication
  • Rate limiting: Configure concurrent call limits and calls-per-second (CPS) throttling
  • Outbound routing: Define origination URIs with priority-based failover and load balancing

Key Features

Dual Authentication

Choose between username/password credentials or IP whitelisting. Combine both methods for maximum security.

Intelligent Routing

Configure multiple origination URIs with priority-based failover and weight-based load balancing for resilient outbound calling.

Rate Limiting

Protect against traffic spikes with configurable concurrent call limits and calls-per-second (CPS) throttling.

Kamailio Integration

Seamless integration with Kamailio SIP proxy for robust routing, authentication, and load balancing infrastructure.

Credentials

Credentials provide username/password authentication for your SIP trunk. You can create multiple credentials per trunk for different devices or use cases. Passwords are securely hashed and never returned in API responses after creation.

View Credentials Documentation

IP Access Control Lists

IP Access Control Lists (IP ACLs) enable IP-based authentication by whitelisting specific IPv4 addresses. Devices calling from whitelisted IPs can use the trunk without password authentication. This is ideal for PBX systems, SIP gateways, and carrier interconnections with static IP addresses.

View IP ACL Documentation

Origination URIs

Origination URIs define where outbound calls from your trunk should be routed. Configure multiple URIs with priority-based failover (lower priority tried first) and weight-based load balancing (higher weight receives more traffic). This enables resilient, distributed call routing with automatic failover.

View Origination URI Documentation

Authentication Methods

Username/Password

SIP digest authentication using credentials. Ideal for devices with dynamic IP addresses or mobile softphones. Kamailio validates credentials against the subscriber database.

Works from any IP address
Multiple credentials per trunk
Secure password hashing

IP Whitelisting

IP-based authentication without passwords. Best for PBX systems, SIP gateways, and carrier connections with static IP addresses. Provides higher security for production deployments.

No password required
Enhanced security
Requires static IP addresses

Getting Started

Quick Setup Guide

  1. 1

    Create a Trunk

    Use the Create Trunk endpoint to provision a new SIP trunk. You'll receive a unique SIP domain and trunk ID.

  2. 2

    Configure Authentication

    Add credentials for password authentication or configure IP ACLs for IP-based authentication.

  3. 3

    Set Up Routing

    Configure origination URIs to define where outbound calls should be routed. Set priorities for failover and weights for load balancing.

  4. 4

    Test Your Trunk

    Configure your SIP client with the trunk's domain and credentials, then make a test call to verify everything is working correctly.