Create Outbound Trunk

To create an outbound trunk, go to the Voice section, select Outbound Trunks, and click Create new (Fig. 1).

Fig. 1 Creating a new Outbound Trunk

The Create Outbound Trunk page will open. Enter the Friendly Name and Allowed SIP IP addresses (Fig. 2).

Fig. 2 Outbound Trunks settings

In addition to basic settings, advanced options are available and can be left unchanged unless required. These options are grouped into sections.

Authentication

The Authentication section allows you to configure how your system authorizes the outbound trunk. The following authentication methods are available:

1. Credentials & IP-Based

This method is selected by default when creating an outbound trunk. It uses trunk credentials and allowed IP addresses to authenticate outbound calls (Fig. 3).

• Allowed IP addresses - your system’s IP address from which calls are sent to DIDWW.

• Allowed RTP IP addresses - your RTP addresses from which audio packets will be relayed to DIDWW.

Note

By default, a trunk cannot be created without adding at least one Allowed SIP IP address. To allow any IP address (not recommended for security reasons), you can add 0.0.0.0/0.

Fig. 3 Authentication section with Credentials & IP-Based option.

2. Twilio Account SID

This method enables trunk creation for Twilio integration (Fig. 4). For more details, see the Twilio Integration Guide.

• Accound SID - a 34 character string that uniquely identifies Twilio account.

Fig. 4 Authentication section with Twilio Account SID option.

Media

The Media section (Fig. 5) provides options to configure how media (audio packets) is handled for outbound trunks. These settings ensure compatibility and enhance security during call setup and transmission.

1. Media Settings

• Force Symmetric RTP: When enabled, the trunk operates in Symmetric RTP/COMEDIA mode.

• RTP Ping: When enabled, RTP ping is used to establish the connection for a call.

2. Media Encryption

The Media Encryption Mode dropdown allows you to select the type of encryption for securing media (audio packets). The following options are available:

• Disabled: Media encryption is turned off.

• SRTP SDES: Secure Real-Time Transport Protocol (SRTP) encryption using Session Description Protocol Security Descriptions (SDES).

• SRTP DTLS: SRTP encryption using Datagram Transport Layer Security (DTLS).

• ZRTP: SRTP encryption using ZRTP (key exchange protocol for securing VoIP calls).

Note

Media encryption is not enabled by default. To enable this feature, contact sales@didww.com.

Fig. 5 Media Settings

Termination

The Termination section allows you to configure Limits and Notifications for outbound trunk usage, as well as manage CLI Settings and Destination Dialing Settings.

1. Limits and Notification

• 24-hour limit (USD): Sets the maximum amount of funds allowed per trunk over a rolling 24-hour period. If this limit is reached, traffic on the trunk is blocked, and active calls will be disconnected within a few minutes.

• Capacity limit: Specifies the maximum number of simultaneous calls allowed per trunk.

• Voice OUT Trunk usage limit notification: Sends an email notification when 80% of the 24-hour limit is reached. Notifications are sent once every 12 hours.

Note

The default 24-hour limit is $3000. The minimum limit is $50, and the maximum limit is $10000.

Fig. 6 Limits and Notification configurations

2. CLI Settings

On CLI Mismatch

A CLI mismatch occurs when numbers from other providers are used as the CLI or when the CLI does not match any numbers acquired via DIDWW. In this situation, you can choose one of the following options:

• Send Original CLI: DIDWW will pass the “From” header value from your system to the PSTN gateway without modification.

• Reject Call: DIDWW will reject the call if the “From” header value does not match any DID numbers allowed in the CLI Settings list.

Fig. 7 CLI Mismatch options

Allow any DID(s) as CLI for Voice OUT

When Allow any DID(s) for Voice OUT toggle is enabled, all supported numbers are automatically used as the CLI by default (Fig. 8).

Fig. 8 Allowing All DIDs

Allow specific DIDs as CLI for Voice OUT

When Allow any DID(s) for Voice OUT toggle is disabled, only numbers added to the Allowed CLI(s) list can be used as the CLI (Fig. 9).

Note

The Available CLI(s) list displays only DID numbers that support the Voice OUT feature with local termination. DIDs with the Voice OUT global routes feature are not included in this list.

Fig. 9 CLI Settings

Tip

To define allowed CLIs:

1. Use the filters to narrow down the list of Available CLI(s).

2. Select the desired numbers from the Available CLI(s) list.

3. Click the > button to add them to the Allowed CLI(s) list.

4. If you want to allow all listed CLIs, click Add all to move all numbers to the Allowed CLI(s) list.

5. To remove a number from the Allowed CLI(s) list, select the number and click the < button.

3. Destination Dialing Settings

The Destination Dialing Settings section allows you to restrict calls to unwanted destinations using the following methods:

Allow All

This method allows calls to all destinations, except those specified in the listed prefixes.

For example, the following configuration allows calls to all destinations except:

• London, UK (4420)

• Ireland (353)

• New York, US (1212)

Fig. 10 Allow all, except for the specified

Reject All

This method rejects calls to all destinations, except those specified in the listed prefixes.

For example, the following configuration rejects calls to all destinations except:

• Bogota, Colombia (571)

• Lancaster, US (1740)

• Mobile, Denmark (4592)

Fig. 11 Reject all, except for the specified

Emergency Calling

For detailed instructions on setting up the Emergency Calling service with an outbound trunk, see Emergency Calling Setup.

Outbound Trunk Credentials

After creating an outbound SIP trunk, you can view its SIP credentials by clicking the key icon in the Credentials column (Fig. 12).

Fig. 12 Accessing SIP credentials.

The SIP credentials dialog provides the following details (Fig. 13):

• Auth type: Displays the authentication type for the trunk (e.g., Credentials & IP-Based).

• Username: The unique username assigned to the SIP trunk.

• Password: The SIP trunk password. You can click the eye icon to view the password or the regenerate icon to create a new password.

• Host(s): Lists the hostnames of the SIP servers available for the trunk.

• Allowed SIP IPs: Displays the IP addresses permitted to send traffic to the SIP trunk.

• Allowed Voice OUT CLI(s): Indicates the caller IDs that can be used for outbound traffic.

• Emergency calling CLI(s): Displays the caller IDs that can be used for emergency calling.

Fig. 13 SIP credentials details

Share SIP Credentials

The Share button allows you to securely send the SIP credentials to a system administrator or another authorized user for configuring the outbound trunk.

Additional Information

Outbound Dialing

Learn about configuring outbound dialing, including number format, local routes, and short numbers.

Outbound Dialing

Termination Services Technical Data

Explore technical specifications and detailed information on termination services, including supported network protocols, signaling endpoints, encryption options, codecs, and other SIP protocol details.

SIP Protocol Details