In a recent article about Lucent's PacketStar Internet telephony gateway, I noted that it was able to scale to up to 2 million Internet telephony calls per day (http://www.tmcnet.com/tmcnet/columns/rich011999.htm). Within my write-up, I mentioned that unlike the PacketStar, many gateways are based on DSP resource boards. Considerable mud slinging takes place between these board vendors when it comes to determining the scalability of their various solutions.

There are many ways to build an internet telephony gateway. If you are Cisco, you simply add the IP telephony components onto your router and produce a merged IP telephony/router solution. Cisco is by no means the only company taking this approach. It is also favored by Motorola, among others.

If you are one of the founders of the Internet telephony gateway market, such as VocalTec, you purchase DSP resource boards and write software that provides a complete Internet telephony gateway solution sans router.

There are many reasons why you might prefer a PC- or SPARC-based gateway, and many reasons why you might prefer a router-based gateway. Other options, such as a PBX-based gateway, make sense as well. Please see my Q2 1998 Publisher's Outlook in Internet Telephony Magazine for more information at http://www.tmcnet.com/articles/itmag/2ndquarter/pubout001.htm.

You may think the mud slinging stops at board-level vendors. Don't count on it. I received several comments from gateway vendors who relied on DSP resource boards. According to these vendors, Lucent's claims should be taken with a grain of salt as well.

Thankfully, TMC labs, our in-house testing facility, has just been expanded, and we will soon have a shot at testing the claims made by the various gateway vendors. In the meantime, the scalability race is getting more exciting. Recently, DSP board-level vendors have been focusing on providing carrier-class gateway components by souping up the port densities on their boards as well.

In fact, Natural Microsystems (NMS), the company that helped spearhead the introduction of PC-based Internet telephony gateways, recently announced that their AG 4000 can handle a full 60 ports of IP telephony per board. The technology enabler in this case is the next generation of DSP chip from TI . This chip, the 320C549, results in a full 100 MIPs. In addition, a 486 CPU controller chip increases on-board processing efficiency and can help keep up with the bandwidth requirements of the PCI bus.

As opposed to fixed IP telephony gateways, systems built with the NMS AG 4000 can also handle fax and voice processing. Also, there is a PSTN telephony interface on each port. Using AG series boards, a developer may handle prepaid calling card and other related applications on the same platform that handles IP telephony... This aids in resource sharing and reduces developer learning curves.

In the cut-throat world of IP telephony, where vendors are vying for a small percentage lead over each other in terms of processing power or scalability, the only constant we will see is Moore's Law, which promises more and more processing power in smaller and more innovative packages. With competition and the effects of Moore's Law, the offerings in the Internet telephony market are getting more and more attractive.

Among these offerings are the components that NMS supplies to a broad array of IP telephony gateway vendors. Expect a host of these vendors to release more powerful gateways in the upcoming months based on NMS's new board density breakthroughs.

Rich Tehrani welcomes comments at rtehrani@tmcnet.com.