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Product Reviews
May 2002

TMC Labs Compares Leading IP-PBXs

If you have one IP-PBX manufacturer, it�s a �bleeding edge� innovation. Two IP-PBX manufacturers is cause to take notice. Three IP-PBX manufacturers constitutes a trend. Four IP-PBX manufacturers is an industry; and anything more than that is certainly an indicator that IP-PBXs are going mainstream. TMC Labs is happy to report that today at least nine vendors manufacture IP-PBX systems, which is certainly a sign of good things to come for the IP-PBX market. While most phone systems sold today are still traditional PBXs, multi-billion dollar companies such as Cisco, Avaya, Siemens, and others have seen the writing on the wall � one-wire to the desktop voice and data convergence is not just a passing fad, but the future of corporate phone systems.

A few years ago, Selsius Systems was the only game in town. Cisco Systems purchased their technology making it the foundation of Cisco�s AVVID product line. Soon after, 3Com followed suit by acquiring NBX, whose technology underpinned 3Com�s IP PBX offering, the NBX-25. Today, with so many different IP-PBX manufacturers, TMC Labs feels it�s time to offer a thorough examination of the leading IP-PBX phone systems.

TMC Labs contacted the leading IP-PBX vendors several months in advance and invited them to ship us their product for an in-depth comparison. Due to some inventory and timing issues we were not able to acquire all the products for this comparison. As such, TMC Labs interviewed product managers and system engineers to determine the feature-set for each individual IP-PBX to be included in the IP-PBX Comparison Chart (See pages 36-37). We should point out we did not give any ratings or determine if the product merited an Editors� Choice Award to any product we did not actually test. We will certainly attempt to test drive those products that we were not able to acquire in time for this feature.

Before we actually began our IP-PBX comparison, it bears mentioning that our definition of an IP-PBX may not meet others� criteria. We consider an IP-PBX to be: �A phone system that utilizes Ethernet phones for true one-wire to the desktop � converging both voice and data across a single network wire.� We should point out that there are many flavors of IP-PBXs: Traditional PBXs with add-on VoIP cards, PC-PBXs with VoIP add-on cards, and next-generation routers/switches with embedded VoIP functionality. We focused most of our attention on this last genre, the router/switch IP-PBXs, although we did include a couple of PC-PBXs with VoIP capabilities.

Typically these routers/switches were designed with IP in their �core� and then telephony/voice was added on top. On the other hand, traditional PBXs and PC-PBXs were designed with telephony/voice at their very core and then IP was added on top. We were tempted to call these VoIP-enabled traditional PBXs and PC-PBXs �IP-enabled PC/PBXs� as opposed to �IP-PBXs�, but we felt that this distinction was probably overkill.

For example, several PC-PBXs, such as Altigen and Artisoft, now have VoIP trunking/gateway functionality via a VoIP telephony board. Both support using NetMeeting as an H.323 �soft phone� client and even hardware H.323 phone sets, such as PolyCom�s SoundPoint IP. However both Artisoft and Altigen still were designed with traditional analog phones in mind and VoIP functionality is more of a �feature add-on.� Still, we would consider both Artisoft and Altigen true IP-PBXs since they support both analog and more importantly � Ethernet phones to the desktop. Thus, Artisoft and Altigen can be classified both as a PC-PBX and an IP-PBX, or a PC-PBX with IP-PBX functionality.

One other type of phone system also exists. These systems that have some VoIP functionality, but do not support Ethernet phones; we dubbed them �pseudo IP-PBXs.� For example, Shoreline Communications has a product that utilizes analog phones, but has an Ethernet interface that allows �VoIP trunking/gateway� access to branch offices. With a Shoreline unit on both ends of a WAN interface, a branch office can connect to headquarters by picking up their analog phone, dialing an extension, and then have the call routed via VoIP across the WAN link.
However, for customers with one office and just a single Shoreline unit, no VoIP gateway functionality is needed, and the Shoreline system merely becomes a regular PBX. To be frank, we�re not exactly sure how to classify Shoreline�s product, since it does have VoIP capabilities yet it doesn�t offer Ethernet phone capabilities � which is part of our IP-PBX definition. Shoreline themselves call their product an IP-PBX, but we are hesitant to define it as such, since again, it doesn�t meet our criteria of supporting Ethernet IP phones to the desktop.

The IP-PBX products we evaluated include 3Com, Alcatel, Avaya, Cisco, ESI, Ericcson, Siemens, and NEC. We also included Mitel and Artisoft to the Comparison Chart as �last minute� entrants. Many, but not all of them are switches/routers with VoIP embedded functionality. Some are traditional PBXs with a VoIP add-on card. However all of these solutions offer �one-wire� to the desktop Ethernet phone solutions. One important note on the Comparison Chart: It was very difficult to get comparable pricing structures amongst all of the IP-PBXs. Each vendor has different pricing structures making it very difficult to get comparable figures. This was largely the case because price adjustments vary depending upon final IP-PBX configuration. Nevertheless, we decided to include the figures submitted to us hopefully providing some sense of cost. But by no means should one use these figures to compare one vendor�s price tag versus another. With that said, let�s begin our comparison.


Today, customers certainly have more choices when selecting an IP-PBX. The market has matured to the point that CIOs/CTOs are seriously considering purchasing IP-PBXs when just a short two years ago they feared the technology was not ready for prime-time. It is true that many of the IP-PBX vendors use proprietary VoIP protocols � often a flavor of H.323, but not 100 percent H.323-compliant, which means you can�t use third-party VoIP phones. They claim this is necessary to offer optimal VoIP performance, which certainly may be true, but we believe the IP-PBX vendors should still support H.323 and/or the SIP protocols, which will allow customers to choose �best of breed� VoIP Ethernet phones or perhaps the cheapest one if that is their choice.

It�s difficult to say which IP-PBX is the �best� when all of the IP-PBXs we examined each have their own strengths and weaknesses. Factors to be considered include price, scalability, flexibility, redundancy, openness, features, ease of use, support for third-party applications, CTI support, support for legacy phones, and ease of administration.

When committing to a 100 percent VoIP solution, some CTOs just may not want to jump in with both feet. A more cautious CTO will look for an IP-PBX that supports a hybrid environment, supporting both analog/digital phones and VoIP phones. Some IP-PBX vendors do support hybrid environments, while others such as Siemens have committed themselves to a 100 percent pure IP solution with their HiPath 5000 product line. In fact, the HiPath 5000 is a virtual softswitch IP-PBX with just an Ethernet port and no TDM interfaces, thus requiring an external gateway for trunk access.

We liked the various IP-PBXs for various reasons. We liked the Cisco product since it was based on the first VoIP phone and helped jumpstart the voice/data convergence market.

In addition, Cisco is a 100 percent pure IP solution and doesn�t inherit any legacy telephony baggage. In addition, Cisco appears focused on the large enterprise and has thus far mostly ignored the small to mid-sized enterprise.

On the other hand, 3Com and ESI are targeting small to mid-sized business; and we especially liked their ease of use and ease of installation. Avaya is another company targeting the mid-sized market and they have many years of telephony experience with their well-known and very popular Definity PBX, which still exists, but has evolved into their new IP-PBX portfolio. With many years under their belt, Avaya was able to leverage their Definity feature set to the IP-PBX product line.

Alcatel was a lab favorite because it is the only true �open� system we examined and we were impressed with Alcatel�s multimedia contact center features. In addition, it is one of just a few IP-PBXs that support third-party H.323 and SIP phones. Ericsson claims their product works with H.323 phones as well.

Altigen and Artisoft are two of our favorite PC-based phone systems that were years ahead of their time by choosing the Windows platform to base their phone system upon. By doing so, this allowed both Altigen and Artisoft to quickly and easily add VoIP functionality simply by adding an IP telephony board. Certainly, if any new technology comes to market, both of them could easily adapt. Due to an open architecture, Altigen and Artisoft have been able to easily add more functionality, such as call center features, to their product lines. Thus, companies need not worry about their phone system becoming outdated by choosing either one of these platforms.

NEC features a modular architecture that allows corporations to slowly migrate to VoIP without committing immediately to it 100 percent. Like the NEC product, the HiPath 3000 supports a hybrid environment to allow for gradual migration to VoIP.

According to In-Stat/MDR, the LAN telephony market � despite being a mere three years old � reached approximately one billion dollars in 2001, more than tripling the sales for the prior year. With stricter budgets and the need for cost-cutting, IP-PBXs have key advantages over their traditional PBX siblings, including free intra-network calling to branch offices and much easier management. One other key advantage not often mentioned with IP-PBXs is that it saves money when moving, changing, or adding a phone. For instance, a user can simply move his phone from one cubicle to another cubicle �plug and play� style. This can be done without requiring the resident telecom guru to reprogram the PBX to let the PBX know the extension has been moved. The IP-PBXs in this comparison are all good solutions; it�s just a matter of which IP-PBX best fits your needs.

[ Return To The May 2002 Table Of Contents ]

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