Carriers define the destinations of VoIP calls that are switched by DUAL Softswitch. They are usually the gateways, gatekeepers or SIP servers operated by the telecommunications companies from which you buy termination. Each carrier is assigned a unique number by DUAL Softswitch, and this number can be used to upload the optional routing settings for a tariff.
You view a list of defined carriers by clicking on the Carriers link in the Routing box on the left sidebar of the DUAL Softswitch Administration System. Click on the name of a carrier to view or change that carrier's properties. Above the table, there are two links for creating new carriers. One link can be used for an H.323 carrier and the other link creates a SIP carrier.
For H.323 carriers, DUAL Softswitch supports Gateway to Gateway and Gatekeeper to Gatekeeper operations. Carriers' gateways or gatekeepers must have fixed public IP address and must authenticate DUAL Softswitch's calls by fixed IP address.
In contrast, SIP carriers can be defined by either IP address or DNS name, allowing them to use dynamic IP addresses. Digest authentication is supported, so DUAL Softswitch's calls can be authenticated using an account name and password combination. SIP carriers can be set up as a SIP Proxy or a Registrar.
The pages in the Administrative System for defining H.323 and SIP carriers are very similar. Each setting is explained on the web page.
Once you have set up a carrier, you will need to test that it accepts calls as you expect. You can do this using DUAL Softswitch's direct carrier selection feature. This is only available to calls made from account 100001, which is a special administrative account.
To make a test call, dial:
* [Route number] * Destination number
Each carrier has a unique Route Number, and this can be found on Carriers page. The destination number should be dialled in accordance with the geographical options defined for account 100001. DUAL Softswitch will perform the necessary digit manipulation. You can use this testing method for both H.323 and SIP carriers. You may need to reconfigure your VoIP device to enable this feature.
Real time monitoring is also available through a Telnet server on DUAL Softswitch. This can be useful for fault investigation. Please contact the DUAL Softswitch support team for more information.
We advise that you use special settings when defining carriers for Betamax products such as VoiceTrading and SIPTraffic:
|•||If you plan to use Least Cost Routing for a Betamax carrier by uploading the carrier's rates, then you must set the carrier up as H.323 (gateway) and not SIP. Betamax's SIP servers always send a 183 (Session Progress) message as soon as they receive a call setup. This incorrect condition implies that the destination subscriber's telephone is ringing. This causes a voice channel to be negotiated, which means that if the call is subsequently rejected, the call will not overflow to further carriers. Setting up the carrier as H.323 means that you need to alter the account settings on your Betamax control panel to allow authentication from DUAL Softswitch's fixed IP address.|
|•||Set Ignore Progress on the carrier. With H.323, Betamax always send and H.225 Progress message as soon as they receive a call set up. DUAL Softswitch should not act on this message, because it will stop Alternative Routing from working if the call subsequently fails. Media negotiation will be deferred until an H.225 Alerting message is received from Betamax.|
|•||Set Add Progress on the carrier. This prevents double-ringing being heard on some VoIP clients.|
|•||Set the Single G.729 on the carrier to avoid one way audio problems when multiple G.729 annexes are offered by the caller.|