The Trunks feature allows you to forward calls made to an Account to a specified path (IP based forwarding).

Trunks and Trunk Connections setup in >=2022 could be found here:

https://support.sippysoft.com/a/solutions/articles/3000118527


The trunk may be triggered in two call scenarios:

  1. Call from a DID number to the number registered on the Account device. This is the scenario when a call arrives from a DID number (in the DID Pool section) and the softswitch routes it to the registered account. The web GUI has an option inside Incoming Routing that allows you to forward calls from a DID number to the number selected in the Incoming Routing section of the Account TRUNK/PBX server

  2. When an On-net call (e.g. from Account to Account) arrives on an Account and the system routes it to a specified Trunk 


Use of fields on the Trunks page:

  • Name - desired name of the Trunk. Unique within one Account
  • Description - optional description of the Trunk
  • Main Destination - the main field on the Trunks page that requires input of the IP address (or hostname) of the system where the calls will be forwarded
  • Main Username/Main Password - enter the appropriate information needed for digest authentication (in case your Trunk requires it). "Main" references to "Main destination"
  • Backup Destination - the backup IP that may be attempted if the "Main Destination" is unreachable or if a 5xx error is received
  • Backup Username/Backup Password - enter the appropriate information needed for digest authentication (in case your Trunk requires it). "Backup" references to "Backup destination"
  • Capacity - desired number of Concurrent Calls (CC) to be allowed through this Trunk
  • Max CPS - desired number of Calls Per Second (CPS) to be allowed through this Trunk
  • Outbound CLD - optional parameter that gives you the ability to convert/translate the incoming CLD into some other number
  • Main Outbound IP - specify the appropriate IP address from the list of IPs assigned to your environment. Thus, Sippy would route SIP requests to the Trunk via the selected IP. It is useful when your PBX demands an exact IP for the authentication of traffic from Sippy

  • Backup Outbound IP - specify the appropriate IP address from the list of IPs assigned to your environment. Thus, Sippy would route SIP requests to the Trunk via the selected IP if the "Backup Destination" is triggered

  • From Domain - changes the IP address in the "From" header field of the INVITE request (made to a PBX/vendor) to a domain name  

  • Random Call-id - optional setting that will allow outbound call IDs to be randomized.  This prevents PBX/vendor from seeing the IP addresses when UAs include them in the call IDs


How to setup a Trunk:

1) Open the Accounts page and press the drop-down "Action" menu (see screenshot below):

2) Select the Trunks sub-menu (marked as 2 on the screenshot)


3) On the opened Trunks page, press the "Add New" button to create a new Trunk:


4) It's enough to fill at least Name and Main Destination 

Or fill-in all fields with your information following the format used in the screenshot below (description for each field see at the top of the page)


Don't forget to fill-in "Main Username" and "Main Password" if digest authentication is required on the Trunk's end.


Setup of Trunks and Trunk Connections in >=2022 version is described in a separate documentation:

https://support.sippysoft.com/a/solutions/articles/3000118527


Incoming Routing setup:

The system allows you to configure specific routing options for incoming calls to an Account.

For example:

If Account A calls B (for example a DID number), the call is routed to the specified trunk (PBX, connection etc.) which was configured in the Account properties of "Incoming Routing" and not to the registered UA (which the Account assigned to B). Alternatively, you can add the Account to the "Incoming Routing" and the call will be forwarded to the registered UA.


Source field - DID number assigned to the Account or On-Net Calls for general On-net scenarios

You can also configure routing from calls that come from On-Net through the (Source field).  So you can route On-Net calls that come to this Account to either Registered UA or some Trunk.


Destination field - external PBX, gateway, particular connection, etc. configured as a Trunk or Registered Account to forward the calls to UA.


Fwd DID Mode changes the outbound INVITE based on the specified setting:

  • If set to Off, case Destination is Registered UA, Account's username would be placed in RURI and From header of outbound INVITE. Case Destination is some Trunk, the original CLD [DID number] would be placed in RURI and From.
  • If set to Forward DID in URI, the original CLD [DID number] would be placed in RURI and From headers of outbound INVITE for both Destination = Trunk or Registered UA.
  • If set to Diversion Header, case Destination is Registered UA, Account's username would be placed in RURI and From header, while DID number would be added to Diversion header of outbound INVITE. Case Destination is some Trunk, the original CLD [DID number] would be placed in RURI and From header, while Outbound CLD of Trunk Connection would be placed to Diversion header.


Self Managed - whether an Account is allowed to change Destination and/or Outbound CLD from its self-care UI



Scenario #1: Onnet calls -> Trunk


When the Trunk is created, open the "Incoming Routing" page (marked as 3 on the "How to set up a Trunk" screenshot)  and select the Trunk required for the Source: On-Net Calls (as shown below):

FWD DID Mode is not compatible with the configuration above and will not work


The Self Managed checkbox permits the management of Trunks on the Account's web self-care interface 

So, end-users/Accounts may Route all incoming On-Net calls that arrive on the Account to the desired Connection.



Click on the diskette icon to apply routing changes (see the screenshot above).



Scenario #2: DID -> Trunk


When the Trunk is created, open the "Incoming Routing" page (marked as 3 on the "How to set up a Trunk" screenshot)  and select the Trunk required for the Source: DID <exact DID number>:

FWD DID Mode allows you to keep the original CLD number forwarded to the selected Trunk


Selecting the Self Managed option allows you to manage Trunks on the Account's web self-care interface.

So, end-users/Accounts may route all incoming On-Net calls that arrive on the Account to the desired Connection (screenshot shown in scenario #1).


Click on the diskette icon to apply routing changes (see the screenshot above).