July 2000

Open Sesame For IP Telephony Application Development

BY MARC ROBINS

What's the big deal? Working closely with Alan Cox (for those not in the know, Cox is the keeper of the Linux kernel, and is Linus Torvald's "right-hand man"), David Erhart, Quicknet's VP of engineering, and in-house Linux guru Greg Herlein successfully lobbied to get the source code for Quicknet's Linux drivers released as part of all new Linux kernels, under the GNU Public License (GPL). All new versions of Linux, from version 2.21.14 onwards -- from Red Hat, SuSE, TurboLinux, Debian, Caldera, and Corel -- will incorporate this source code.

OK. So what does this mean? Now, whenever Linux is installed and configured on a server, a new option exists to add drivers for "Telephony Support" -- a separate category that will serve as the home for the myriad telephony board drivers out there in the market. Dave and Greg had to lobby hard to convince Cox that a telephony device was an entirely different animal than a sound card, and that extending the sound card category simply would not suffice.

In addition to creating the "Telephony Support" option, a new telephony card device broker was also created that serves to pave the way for other Linux-ready resources. Other vendors register their boards with this broker during the install procedure, enabling the kernel to recognize the hardware.

The Quicknet Linux drivers include multi-card support, permitting developers to create multi-line Internet gateways and private inter-office Internet telephony phone systems. The drivers include license-free access to G.711, G.723.1, and TrueSpeech 4.1-8.5, enabling developers to create high quality Internet telephony applications without licensing costs or royalties.

A Precedent For Linux Telephony
OK, OK. So what does all this really mean? Quicknet, in being the first to step up to the plate and courageously offer up its prized source code, leads the effort to create an open telephony API on Linux. The stage is now set for a flowering of IP telephony innovation and application development on Linux. This action instantly created a broad, new developer base for their products. Because everything is now open, developers are encouraged to create patches, extensions, etc. to their code. And this action created the "climate" for nifty new applications that the vendor didn't have time for or didn't think of, including quite possibly the next killer Internet telephony app.

Due to all this open source Linux activity, the Linux telephony movement is catching fire. Other vendors are starting to follow suit, including Dialogic/Intel, which has promised open Linux drivers sometime in August (FYI, Intel is an equity stakeholder in Red Hat). According to Greg Herlein, open sourcing has accelerated several ongoing projects, including the OpenH323 project. (Developers take note: This sharing of driver source code is the first phase in an ongoing process, and there's still a lot of work to be done. Middleware still needs to be created -- a hardware abstraction layer similar to TAPI in the Windows world. Then there are the applications themselves.)

To help you get started, the source code for Quicknet's Linux drivers is available on the company's Web site. Other places to visit to check out what's up on the open source Linux telephony front are www.linuxtelephony.com and www.openphone.org. Openphone.org is home to the Quicknet-sponsored OpenPhone project, an open-source effort to build a common Internet telephony application that can be used across all platforms. OpenPhone is envisioned with a modular design and support for "plug-ins" that allow different audio transports, and different signaling transports. The application will provide a way for open source plug-ins to be written, and will also add the ability for commercial binary plug-ins to be added to provide interoperability with various commercial Voice-over-IP (VoIP) network termination services. 

Marc Robins is Vice President of Publications, Associate Group Publisher, and Group Editorial Director. His column, Mind Share, appears monthly in the pages of INTERNET TELEPHONY magazine. Marc looks forward to your feedback.

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