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when was the last time you spent any quality time with your PBX? If you're like most businesses, it's been a while. Yes, you add trunks, you reconfigure voice mail accounts. But it's not like your data network, where all sorts of things-good and bad-are going on all the time.
What's going to happen in the world of voice and data "convergence?" How will you manage a system that's equal parts telecom and datacom-like the burgeoning class of new telephony systems called "IP-PBXs"?
Mier Communications recently tested and reviewed a half-dozen leading IP-PBXs (see BCR, January 2000, pp. 35-42). And while we found some aspects in common, these products turned out to be much more different than alike in architectures, features and capabilities. The same is true for their management requirements and capabilities.
The IP-PBXs we reviewed all support voiceover-IP (VOM), which enables these systems to deliver real-time voice calls over traditional data networks. But the options and access they offer administrators for managing the VOIP support differ widely.
Table I ("Piecing Together IP-PBXs") shows the diverse components that comprise today's IP-PBXs. Each is an individually addressable IP "node," which means that all control messages and voice communications between these nodes are carried via an IP network. That also means they can be physically distributed anywhere; they need only IP connectivity between them. The IP-PBX system may actually span a campus, city, state or country.
Except for Shoreline Teleworks'(www. shoretel.com) Shoregear and 3Com Corp.'s (www.3com.com) NBX 100, all the systems we reviewed for this article rely on a Microsoft NT Server as their central call controller. In conventional digital PBXs a CPU performs similar functions, and classical PBXs have time division multiplexing (TDM)-based switching fabric instead of an IP data network.
Classical PBXs also are invariably selfcontained within the same chassis, as are the new-generation systems from AltiGen Communications (www.altigen.com) and Vertical Networks (www.vertical.com). However, unlike classical PBXs, AltiGen's and Vertical's systems can deliver phone calls in VOIP form over an IP network.
Four Management Aspects
There are many ways to view the management characteristics of networking products, but four main aspects are applicable to virtually all modem network systems, including IP-PBXs. They are:
* Configuration: Embodies most of what the ISO and other standards...