Four Ways to Do VoIP

FRAMINGHAM (03/06/2000) - If you want to get started today on a transition to voice over IP, there are four options: gateways, IP PBXs, converged appliances, and other.

Gateways: popular, but lack features

A voice-over-IP gateway can be loosely defined as a mechanism that takes circuit-switched voice from a traditional PBX, converts it to IP and transfers it across a LAN or WAN to another gateway where it is reconstituted back into a format that is understood by the receiving phone system.

Gateway functionality can be obtained through stand-alone boxes, modules or chassis cards for proprietary boxes; also expandable routers or software and expansion cards for Windows NT servers.

For example, Cisco Systems Inc. is taking a modular approach with a voice-over-IP card that fits its 1750, 2600 and 3600 series routers. Suda Madabusi, product manager for the Cisco 1750, says all Cisco products can easily be equipped for voice. Cisco says voice packets can be guaranteed via quality-of-service policy implementation on a Cisco-switched network.

Lucent Technologies Inc., Nortel Networks Corp. and Siemens AG offer similar strategies for providing voice-over-IP gateway capabilities in some form or another.

While gateways are the most popular voice-over-IP products on the market -- available from at least 30 vendors -- the key point here is that you have voice packets running over IP. However, the packets are not running on the Internet, and you're not gaining any of the features and capabilities you get by converging voice and data networks.

IP PBXs: great features, scalability lackingIP PBXs, such as Altigen's AltiServe and Artisoft's TeleVantage, are great if you have the luxury of designing your system from the ground up. IP PBXs are complete phone systems, usually with IP phone options that include many of the IP telephony applications, such as managing your phone from your desktop PC, multiline call control and automatic call distribution.

IP PBXs are usually NT servers with telephony software and voice cards.

Disadvantages often include scalability and a dial tone that's dependent on NT, which doesn't offer the same uptime as a switched phone network.

Until recently, IP PBXs have mainly been targeted at small or branch offices with 100 users or less, but Alcatel recently announced OmniPCX, a voice-over-IP system that incorporates gateway and call processing in a single device and can accommodate up to 50,000 users. Additionally, 3Com, Lucent and Cisco have all announced plans to provide the same type of product.

Cisco's Selsius products and 3Com's NBX series fit in this category because the goal of both is to provide the same services as OmniPCX on a large scale.

However, while initial versions of these products are in trial stages, they have not been proven for high numbers of users. Alcatel is the first to stake that claim, and Cisco and 3Com will have products in the future that compete.

3Com now says its product is only for midsize businesses with less than 500 users.

The beauty of an IP PBX is being able to create a distributed system. For example, Nokia's IP Telephony Gateway and Shoreline Teleworks' ShoreGear IPBX allow you to distribute your phone system throughout an IP network, so geographically separated phones -- with features such as direct dial, call forwarding, conferencing and voice mail -- provide the appearance of being connected directly to the local PBX. Alcatel's, 3Com's, Lucent's and Cisco's IP PBXs do not offer these features.

Converged appliances: simplified managementConverged appliances that join phone and data networks provide the simplified management that fulfills the promise of voice over IP. Several vendors offer such appliances. For example, Vertical Networks' InstantOffice offers call services, voice mail, routing and LAN connect for voice and telecom, for a small to midsize office, all included in the same box and managed together.

Also, Praxon's PDX, a modular communications platform, combines voice PBX features with a full complement of data networking, messaging and Internet functions.

Other options: mix and match

Aside from stand-alone gateways, IP PBXs and converged appliances, there's the other category we've defined. Interestingly, this other category is not necessarily the smallest. In fact, given the number of insertion points for voice over IP and the options available, it's probably the largest.

Lucent, for example, has a line of products that allow the convergence of your existing voice with IP system at different points along the chain. Want to IP-enable your existing Definity PBX? PacketStar ITS-E is the option you need.

Want IP-based trunking? You can use the Definity IP Trunk for Enterprise. Want just IP phones? You can buy Definity IP Ethernet Telephones. Want to leave analog phones and fax machines in place, but have an IP PBX? IP ExchangeComm answers the call.

VocalTec also provides piece parts such as the VocalTec Gatekeeper for IP address-to-phone number mapping. There's also VocalTec's InternetPhone, an audio/video/PC phone and the VocalTec Telephony Gateway Series 120 and 2000, two versions of IP public switched telephone network gateways. Additionally, Cisco, Nortel and 3Com have also outlined convergence strategies with products that do everything from single device IP integration to complete infrastructure replacement.

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