Configuring Twilio Interconnect Trunk
Before proceeding with the next steps, you need to purchase a DID on Twilio.
Twilio Interconnect Trunk
Twilio Interconnect is an alternative to the open Internet that provides private connections between your network and Twilio. It offers the best performance and data throughput and the lowest latency. Since your data never touches the public Internet, it also provides the best security and can guarantee quality from end to end.
For more details please check:
Choose the product that is right for you
There are several reasons why Interconnect is the preferred method of connecting to Twilio. High availability, guaranteed data throughput_, quality of service, and enterprise-grade security are just a few of the strong arguments for making use of Twilio Interconnect. If you need highly consistent connectivity between your communication infrastructure and Twilio, then Twilio Interconnect is the right choice likewise, if you have policies (internal or external) that preclude you from sending traffic across the open Internet — for example, HIPAA, PCI, or GDPR.
Twilio Interconnect has several flavors to accommodate various use cases:
Cross Connect allows you to set up a dedicated, physical fiber interconnection with Twilio.
Third-Party Exchange is a way of having a private connection through a third-party provider that Twilio has an exchange agreement with.
VPN is the best option if you want to quickly try something out and play with some ideas, or if you have no presence in any of our or our partners' data centers and wish to have a secure connection to us.
Create a SIP Trunk on the Twilio Platform
To create a new SIP trunk on the Twilio platform, follow these steps:
Sign in to your Twilio Console.
From the left-hand navigation bar, navigate to Elastic SIP Trunking
Alternatively, click the Elastic SIP Trunking icon in the left vertical navigation bar.
Select Manage > Trunks.
Click Create new SIP Trunk.
Enter a friendly name for the trunk, then click Create.
Configure Trunk Termination
After creating the SIP trunk, leave all settings on the General page unchanged and switch to the Termination section. This section defines where outbound calls from PortSIP PBX are sent to Twilio.
Step 1: Configure the Termination SIP URI
In the Termination section, enter a unique Termination SIP URI of your choice.
If the URI status displays Available (shown in green), the URI is valid and can be used.
Click Show localized URIs, then copy the listed URI values.
These localized URIs will be required later when configuring the trunk in PortSIP PBX.
❗Important Make sure to save the full Termination SIP URI information. It will be referenced directly in the PortSIP PBX trunk configuration.
Step 2: Configure Authentication (IP ACL)
Scroll down to the Authentication section.
Under IP Access Control Lists (IP ACLs), create a new ACL entry.
Add the public IP address of your PortSIP PBX.
This IP address can be found on the PortSIP PBX Web Portal Home page.
❗Security Best Practice Using an IP ACL ensures that only your PBX is authorized to send SIP traffic to Twilio.
Step 3: Configure the Credential List
In the Credential List section, create a username and password pair.
Save the credentials.
❗Note These credentials will also be used later when configuring the Twilio trunk in PortSIP PBX.
Click Create to save the Termination configuration.
After saving, proceed to the Origination page to continue the Twilio SIP trunk setup.
Configure Trunk Origination
In the Origination section of the configuration, configure your origination SIP URI, which identifies the network element entry point into your PortSIP PBX. To ensure your calls go over your private connection, include the edge parameter in the URI with the value of the Twilio Interconnect Edge Location where your private connection is configured.
Origination SIP URI Format
Use one of the following formats, depending on whether you reference your PBX by IP address or FQDN.
Using a Public Static IP Address
Using a Fully Qualified Domain Name (FQDN)
Example (Edge Location: Ashburn)
❗Note Do not include curly braces
{}in the actual configuration.
Assign DID Numbers to Your Elastic SIP Trunk
After creating the Elastic SIP Trunk, you must assign one or more DID numbers to it.
Follow these steps in the Twilio Console:
From the left-hand navigation menu, go to: Phone Numbers > Manage > Active Numbers.
Click the phone number you want to assign to the SIP trunk.
On the number details page, locate the Voice Configuration section.
For Configure with, select SIP Trunk.
From the SIP Trunk drop-down list, choose the Elastic SIP Trunk you created earlier.
Click Save Configuration.
Configure the Twilio Interconnect Trunk in PortSIP PBX
The Twilio Interconnect Trunk is configured in PortSIP PBX as a Register-Based Trunk.
You can configure this trunk at either of the following levels:
System Administrator level
The trunk can be shared with one or more tenants.
Tenant Administrator level
The trunk can be used only by that tenant and cannot be shared.
Step 1: Create the Register-Based Trunk
Sign in to the PortSIP PBX Web Portal as a System Administrator or Tenant Administrator.
From the left-hand navigation menu, go to Call Manager > Trunks.
Click Add, then select Register Based Trunk.
Step 2: Configure Basic Trunk Settings
Enter the following information:
Name Enter a friendly name for the trunk (for example,
Twilio-Interconnect-Trunk).Brand Select Twilio Interconnect.
❗Important Selecting the correct brand ensures proper trunk behavior and option defaults.
DID Pool (Tenant Admin level only) If configuring this trunk at the Tenant Administrator level, specify the Twilio DID numbers assigned to this tenant.
❗Important
The tenant can use only the DID numbers in its DID pool to:
Create inbound and outbound call rules
Configure outbound caller IDs for extensions
DID Pool Format Examples
Hostname or IP Address Enter one of the Twilio Interconnect Termination URIs saved earlier, based on the geographic location closest to your PortSIP PBX:
Click Next to continue.
Step 3: Configure Authentication Credentials
Enter the Authentication Name and Password created earlier in the Twilio Credential List.
Click Next.
Step 4: Configure Trunk Options
Need Registration Disable this option.
❗Twilio Interconnect trunks do not accept SIP
REGISTERmessages.Max Concurrent Calls Defines the maximum number of simultaneous calls that PortSIP PBX can establish using this trunk.
Adjust this value based on your Twilio Interconnect capacity and expected traffic.
Leave all other settings at their default values unless you have specific requirements.
Click Next to continue.
Step 5: Assign Tenants and DID Pool (System Admin level only)
❗Note This step is available only when configuring the trunk at the System Administrator level.
Assign the trunk to one or more tenants.
Provide Twilio DID numbers to each tenant using the DID Pool.
❗Important
Each DID can be assigned to only one tenant.
A tenant can use only the DID numbers in its DID pool to:
Create inbound and outbound call rules
Configure outbound caller IDs for extensions
DID Pool Format Examples
Click OK to save the configuration.
Expected Result
The trunk configuration is now complete.
Because Need Registration is disabled, the trunk status will always display as Registered in the trunk list.
This is expected and correct behavior for Twilio Interconnect trunks.
Next Steps
Refer to Twilio Elastic SIP Trunking documentation for platform-specific details.
Proceed to Configuring inbound and outbound calls in PortSIP PBX.
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