PBX for SIP trunking

Christian Stredicke
CEO of Vodia Networks

5.2.0 introduces a small, but important improvement: if an extension has more than one alias number, it will send the called alias number to the registered device on inbound calls. In case a number was called that was not on the list of alias names, it will still pick the primary name of the extension.

The background for this change is that the PBX is not always only used as a pure PBX. Instead because of its functionality to deal with devices that are behind NAT (session border controller) and other features like SRTP encryption, it makes it useful as a trunk engine. Customers register their devices as extension on the PBX. Although the PBX treats this as extensions, what the customer sees is a SIP trunk.

Service providers who are using the Vodia PBX for SIP trunking also can benefit from the fact that the PBX offers PCAP recording for easy, customer-based trouble shooting. The PBX is probably one of the few that support RTCP-XR for SLA monitoring. The automatic blacklisting feature makes it resilient against common scanners. The multi-tenant feature can serve as additional help to reduce the risk of unauthorized access. 

And the fact that the PBX is able to operate on multiple IPv4/IPv6 interfaces makes it possible to run other SIP devices in a private network, while customers see the public interface. It is even possible to have customer register on IPv6, while the private network is still on IPv4.

With the new CDR reporting, it also becomes a lot easier to bill the customer. SIP trunk providers can use the template PHP code to integrate the PBX CDR with their billing systems. Because the PBX is software based, it scales with the availability of powerful server hardware. The support for virtualization makes it possible to have a failover with even calls staying up.

In the private network, customers can run other SIP-compliant PBX. For example we have had a case where a customer was running a Cisco CallManager in the corporate network and needed a solution to interface with the public Internet using the PBX as the session border controller. It worked well.