Telephony middleware? Isn’t that the API—the “driver” as it is sometimes called—that comes with a voice board”? Well, perhaps. But the term “middleware” is borrowed from enterprise client-server computing. It denotes the “connectivity software that consists of a set of enabling services and their APIs that allow multiple processes running on one or more machines to interact across a network”. So the term is more appropriately used for the third-generation of CT environments exemplified by Commetrex’s Open Telecommunications Framework® (OTF) and Dialogic’s CT Media.
But if middleware is the software that comes with a voice board, once the board vendor is chosen what’s left to choose? Just a few years ago the answer was ‘nothing’ since the two were bundled by the board vendor. But open communications has a layered value-adding structure. It’s similar to the PC industry but it’s less efficient, offering participants fewer opportunities to specialize. Throughout the ‘80s and ‘90s there have been three significant value-adding layers: an open computing platform, be it PCI, CompactPCI, or VME; the media-processing and switching resources (boards) bundled with their APIs (and drivers), and the application layer. But that’s changing, and the change is making the open-communications industry more open and efficient.
In the last half of the ‘90s new open interfaces have been published that support further specialization. The ECTF has published S.100, an open client-server system framework and API that promotes application integration and portability. (That’s middleware.) To take matters even further, the MSP Consortium has published M.100, an open-specification for a multi-vendor media-processing software environment. It promotes the portability and integration of media technologies from multiple vendors onto one media-processing resource. The PCI Industrial Computer Manufacturers Group has published specifications that will bring the development efficiencies of the open-communications industry to carrier-class equipment. What this means is that in the coming decade vendors can enter the market without spreading their resources thin, focusing on just piece, such as
- An application
- PC-based middleware
- Boards and their environments
- Network interfaces
- Media-processing firmware
- System-level hardware
This list has expanded by 50% over what it was just a few years ago. But why is that specialization good, and what’s wrong with the way it was done in the early 90s? The answer is that as the technology shaping the industry changes, so must computer telephony.
In the days of first-generation open communications life was simple. We had DOS systems with four-port voice boards that supported voice processing. (The second generation began with MVIP.) But today we have affordable 550-MHz processors and high-function multi-threaded operating systems. Industry-standard PCM highways, such as H.100 interconnect DSP-resource boards with several DSPs, each capable of supporting 60 voice ports. The only effective way to apply such power is to integrate media and applications onto one high-function, high-capacity platform. And today, with CompactPCI supporting open communications’ move into the carrier-equipment market, that platform must be easily scalable to support thousands of ports. So far, the only practicable way to do that is with client-server architectures.
Since media and application competencies are generally limited within one company, value-adding interfaces are required to allow the integration of multi-vendor products onto one platform, just as in the PC industry. What this means is the system integrator can take media-processing hardware resources from one vendor, fax from another, and high-speed data modems from another to create an integrated-media resource on just one board. And instead of one vendor having to develop each application for an integrated-applications communications server, S.100-conforming applications can be selected from companies that specialize in their respective area, such as voice, fax, or data, and integrated onto one common platform.