I have been a product manager in the enterprise media gateway space for a number of years. Over that time, enterprise media gateways have matured from simple toll bypass devices which enabled cheap long distance calling to elements which enable a wide variety of solutions within the hybrid network infrastructure. One of these is the SIP Trunking solution.

SIP Trunking is a service offered by Internet Telephony Services Providers (ITSP) allowing the extension of VoIP connectivity beyond the enterprise and in parallel to the data connectivity requirements. It is essentially a concurrent call routed over the IP backbone of the ITSP. With this converged voice and data service, SIP trunks can offer huge costs savings for the enterprise, eliminating the need for PSTN lines and can deliver a fast Return On Investment (ROI) for the switchover. You can order call paths based on the enterprise needs and these can be added to or removed easily as circumstances changes.

Moving to SIP Trunks requires the connection of the internal network and PBX to the SIP Trunk which can be achieved through a SIP aware border element. Sounds pretty straight forward doesn't it? In reality there are a number of factors that can complicate the situation. First, the majority of enterprise premises do not have SIP enabled PBXs. As much as we hear about VoIP, the majority of on premise PBXs are still legacy TDM PBXs. For these premises, a gateway function is required to convert the SIP Trunk messages to TDM messages that are recognizable by the PBX. Second, for those premise based PBXs that support a SIP interface, there are often interoperability issues with the SIP Trunk due to the varying implementations of the SIP specification. For these premises, again, a gateway function is required to perform the SIP-to-SIP mediation. And third, for those situations where the SIP Trunk can communicate directly with the on premise equipment, it is usually desirable to have a demarcation point between the enterprise network and the service provider's network.

We are in the process of developing a new product which we are currently calling the Dialogic Border Gateway. The Dialogic Border Gateway will enable the connection of virtually any type of network trunk, either a PSTN Trunk or a SIP Trunk, with virtually any premise based PBX, legacy TDM PBX, hybrid PBX, or IP-PBX. The Border Gateway will also provide the required security functions to establish a demarcation point between the enterprise network edge and the service provider network. In future posts I will provide more detail on the Border Gateway product as well as some addition insight into the SIP Trunking market. I welcome others to share their insights in these areas as well.