Our research turned up a total of 25 shipping IP telephony systems. Native IP or IP-centric systems on the market now are Avaya's new IP600, 3Com's NBX 100, Alcatel's OmniPCX 440, Cisco's AVVID/CallManager, Shoreline Communications Inc.'s Communications System, Siemens Enterprise Networks' HiPath 5300/5500, Sphere Communications Inc.'s Sphericall and Vertical Networks' InstantOffice.
The more traditional PBX vendors that offer IP-enabled versions of their erstwhile TDM- and switching-matrix-based PBXs include: Avaya with IP add-ons for the Definity; Mitel, with its Ipera 2000 evolution from the SX-2000; NEC America, with its NEAX 2400 IPX; and Nortel, with add-ons for the Meridian 1 and the Business Communications System, which was the Norstar system.
Our research indicates there isn't widespread adoption of IP-enabled PBXs because the technology is fairly untested. So corporations are deploying native IP PBX systems, such as Cisco's AVVID, experimentally for specific applications or within departments or branch offices, while maintaining their traditional PBXs corporatewide. Furthermore, full-scale deployment of IP PBXs has been hampered because these packages do not offer the array of voice features available on traditional PBXs. However, some IP PBX vendors -- Cisco, for example -- are rapidly adding new phone features to their products to compete more aggressively against the traditional PBXs.
Another notable voice-over-IP product trend is the growing number of complete voice-over-IP systems now offered. These products incorporate one or more voice-over-IP gateway models, along with a voice-over-IP gatekeeper or other high-level voice-over-IP call-control system (also often called a softswitch or call agent), and a management system. As recently as 1999, most vendors offered only piecemeal or partial voice-over-IP systems. With the complete systems, the buyer benefits by having a system that doesn't include a lot of third-party components, which might have been sold as fully interoperable, but may not have been. There is the advantage of working with one vendor/supplier as opposed to many.
Products that fall into our "other" category include software applications for billing and accounting, settlement services that monitor and report transactions for charging back voice-over-IP services within the network, and gateway and gatekeeper/softswitch software, which is typically, though not exclusively, sold to systems integrators and OEMs.
One unique product in the "other" segment is RAD Data Communications' IPmux-4, which provides an unusual form of a voice-over-IP gateway. The product delivers TDM over IP.