From Ezilon.com
VOIP gateways: assessing options for the enterprise
By Ezilon.com Articles
Jan 24, 2006, 20:49
VOIP gateways: assessing options for the enterprise
VOIP gateways have come a long way in a short time, but some critical gaps remain unfilled. In just a few years, the idea of compressing and packetizing voice and sending it over IP data networks has morphed from a PC hobbyist's delight into a long-distance cost-cutting scheme and, lately, into a potential platform for additional applications. Along the way, Voice-over-IP (VOIP) has attracted the attention of practically every category of communications and computing vendor. Traditional voice and data system suppliers have joined the PC software pioneers and special-purpose VOIP gateway developers to offer enterprise network managers a growing variety of products.
VOIP gateway functions are now supported on everything from Windows NT and Sun Solaris servers to PBXs routers and remote access servers. Besides adding VOIP to their usual functions, many of these products also provide fax-over-IP, various other features and functions, and a healthy selection of interfaces, compression algorithms and configuration and management tools.
The fundamental reasons why every communications vendor has, or plans to have, an enterprise VOIP gateway product - and why most enterprise network managers will at least evaluate them - have less to do with tariff arbitrage than with enterprise customers' dependence on private networks.
A pair of VOIP gateways dropped on the ends of an existing point-to-point private line is a relatively inexpensive way to add voice-calling capacity and cut voice-calling costs. Even the largest customers who are getting the best per-minute rates for mice (say, 3 or 4 cents) can benefit, because they are undoubtedly also paying for private data networks that aren't fully used.
The extra capacity on most corporate data networks is no accident. It's there partly because over-provisioning is the easiest way for network managers to avoid end user complaints about throughput delays - at least it's easier than trying to control the users and their applications.
But overprovisioned data nets are also a consequence of the carriers' private-line pricing policies. Fractional T1 services are not widely available, so most network managers have a choice: either lease multiple 56/64-kbps DSO circuits or a full T1, with 24 DSOs. According to Vertical Systems, a full T1 currently costs only about as much as four or five DSOs.
VOIP gateways make efficient use of this idle, paid-for bandwidth capacity. They can compress a standard 64-kbps voice call to 7-13 kbps (i.e., with the G.723.1 voice codec, 5-6 kbps of voice content, plus another 2-7 kbps for packet header information).
Naturally, the VOIP gateway vendors would like to place their products in both enterprise and carrier/ISP networks. But the carriers and ISPs are mired in strategic and regulatory complications, not to mention the technical difficulties associated with making end-to-end calls happen between PSTN and Internet endpoints.
It could take several years for these complex public network issues to be resolved. In the meantime, there's no good reason for the vendors to stand around, especially when it seems that so many enterprise customers could readily benefit by putting VOIP to work in their existing private-line networks.
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