DIDWW outbound trunks enable routing of voice traffic to external destinations via DIDWW termination routes. This section covers the steps how to create and configure outbound trunks, including authentication, media settings, and termination routes for efficient call management.
In addition to the basic settings, advanced authentication options are available below. These settings can be left unchanged unless specific configuration is required.
The Authentication section allows you to configure how your system authorizes the outbound trunk.
Fig. 3 Authentication section with Credentials & IP-Based option.
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
The maximum number of allowed SIP and RTP IPs and subnets is 60.
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.
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.
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.
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 .
The Termination section allows you to configure Limits and Notifications for outbound trunk usage, as well as manage CLI Settings and Destination Dialing Settings.
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.
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.
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.
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.
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.
Tip
To define allowed CLIs:
Use the filters to narrow down the list of Available CLI(s).
Select the desired numbers from the Available CLI(s) list.
Click the > button to add them to the Allowed CLI(s) list.
If you want to allow all listed CLIs, click Add all to move all numbers to the Allowed CLI(s) list.
To remove a number from the Allowed CLI(s) list, select the number and click the < button.
To use the emergency calling service with an outbound trunk, you must first have a DID number that supports emergency services and has emergency service activated.
Follow the steps below to complete the setup:
1. Create & activate emergency calling service
Follow this guide to check your DID eligibility and activate emergency services.
If your outbound trunk uses the Credentials & IP-based authentication method, you can view its credentials by selecting the key icon in the Credentials column on the Outbound Trunks page (see Fig. 12).
Explore technical specifications and detailed information on termination services, including supported network protocols, signaling endpoints, encryption options, codecs, and other SIP protocol details.