Interoperability affects booming VoIP marketplace

As noted before, a 100-or-fewer line system is the typical size deployed in 90 percent of enterprise applications. The 50/50 mix of phones is more theoretical. IP PBX configurations often can't be compared one for one with classical PBXs. For example, stations such as soft phones (software on PCs with a microphone) don't exist in the classical PBX environment. In the IP PBX world, there tends to be more than one station per employee (typically an IP phone and a soft phone, both of which are IP PBX stations). There is seldom more than one station per employee with classical PBXs.

The average per-channel price for voice-over-IP systems (including PSTN/central office replacement switches) was $571. This represents a fairly wide range of prices from a low of $100 per channel (for RAD Data Communications' IPmux-4) to a high of $1,550 per port on Memotec's CX800 system. As it turned out, the median price (around $500) among all voice-over-IP systems included in this analysis virtually matched the average price.

The average per-station price of an IP PBX is $514. This is based on an averaging of 13 systems, ranging from a low per-port price of $331 with Vertical Networks' InstantOffice to a high of about $790 on Alcatel's OmniPCX. It was noted that PBX topologies can vary significantly, especially with so many different station options.

It is noteworthy that more than half of the vendors didn't provide detailed or configuration pricing. Many vendors -- particularly those at the high-capacity end of the market -- don't want to go public with pricing, citing the old line: "It's heavily configuration-dependent." Translation: prices are heavily discounted to major accounts, so the vendors don't want to reveal prices.

Trend no. 4: Peaceful coexistence in the standards arena?

In 1999 many vendors -- speaking mostly off the record -- thought the voice-over-IP standards arena was in a state of utter chaos and would remain so for at least several more years.

At issue was the fact that the most widely embraced standard at that time -- the ITU-T's H.323 umbrella standard -- was far too complex to implement efficiently or interoperably. Originally designed as an end-to-end communications standard for videoconferencing over packet networks, H.323 was retrofitted for voice-over-IP applications. The result was a standard that defines far more functionality than is necessary for most voice-over-IP environments.

H.323 also allows for many options in implementing it, which means vendors interpret the standard in many ways. While flexibility is typically a good thing, it can be problematic where interoperability is concerned.

Also, various incompatible versions of the H.323 standard exist. Version 1, which is not forward-compatible with the most widely supported Version 2; and Versions 3 and 4. Version 3 is a ratified standard at this point but Version 4 was not as we went to press (see graphic, right). Clearly so many versions of the same standard have contributed to industry confusion.

Confusion or not, H.323's Version 2 is the most widely implemented today, present in 49 products out of the 84 we analyzed. However, when we looked at what vendors are planning to do in the standards arena, other standards are gaining some major ground.

These include MGCP, a protocol that addresses control of media gateways, but it does not -- as H.323 does -- specify a complete end-to-end communication. Vendors supporting or planning to support MGCP within the next six months include Alcatel, Avaya, Cisco, Clarent, Dialogic, ECI Telecom, Inter-Tel, Motorola, Netcentrex, Syndeo, Telecom Technologies, Telogy, Unisphere Networks, Vertical Networks and Vsys.

Two variants of MGCP exist: one, per RFC 2705, under control of the IETF, and another version under the auspices of the ISC. Among the 36 products supporting MGCP, 22 support the RFC 2705 specification, while nine specifically support the ISC version.

H.248/Megaco, a joint undertaking of the ITU-T and the IETF, combines elements of the IETF's MGCP with the ITU's H.323. The main thrust of Megaco is to permit greater scalability than allowed by H.323, and to address the technical requirements of multimedia conferencing. At present H.248/Megaco is not nearly as widely supported as H.323 or MGCP, but vendors say they plan to implement it on 30 products within the next six months. The vendors that support H.248/Megaco now or plan to within the next six months are Avaya, Alitgen Communications Inc., Alcatel, Cisco Systems Inc., Clarent, Dialogic Corp., Motorola Inc., Sonus Networks Inc., Unisphere Networks Inc., Vertical Networks and Vive Synergies.

Yet another standard gaining widespread acceptance is SIP. SIP is an application-layer signaling protocol that specifies call control for multiparty sessions, IP phone calls or multimedia distribution. Unlike H.323, which is based on binary-encoding, SIP is a text-based protocol that vendors tell us is much easier to implement.

The vendors that currently or plan to support SIP are Avaya, 3Com, Altigen, Alcatel, Cisco, Com2001, Ericsson, ECI Telecom, NEC, Nortel (on the Business Communications Manager), Nuera, Pingtel, Shoreline, Syndeo, Telecom Technologies, Telogy, VocalData and Vsys. SIP is supported on 24 products and is planned to be implemented on 39 more within the next six months. This will boost SIP's prominence significantly.

When we last examined the standards issue about eight months ago, half of all vendors said they were supporting H.323 in some way. That's still true now, but it is clear that competing standards are encroaching on H.323's territory.

From vendor interviews we conducted for this review, we gleaned a general consensus that by year-end 2002, most (more than 50 percent) voice-over-IP equipment will interoperate. However, this clearly will not be based on one standard but many.

Miercom will be testing these claims in our continuing voice-over-IP interoperability labs, the first of which will run at ComNet 2001 in Washington, D.C. this week.

Trend no. 5: Interoperating partnerships

If a voice-over-IP product is going to work with any other vendor's gear in general, that gear is going to be shipped by Cisco. Twenty-eight vendors say they interoperate with Cisco voice-over-IP products, with 10 reporting that interoperability was achieved specifically with Cisco's AS5300 gateway. That's not surprising, considering the prominence of Cisco's voice-over-IP equipment in enterprise and carrier networks.

The second most frequently cited voice-over-IP partner and product was Microsoft's NetMeeting. A few vendors also reported interoperability with Microsoft's Outlook e-mail application.

Lucent was the third most frequently mentioned partner (by six vendors on various products), although this involves equipment that has now largely been assumed by Avaya. Another reference product for achieving interoperability is RADVision's gatekeeper -- the fourth most commonly cited interoperable partner (by five vendors).

About half of the vendor respondents reported they had conducted widespread interoperability trials, but were generally not willing to go on the record with partners' names -- mainly citing nondisclosure agreements for the lack of specifics.

Our assessment of the thorny voice-over-IP interoperability issue is that while we're seeing more willingness among vendors to cite interoperable partners than a year ago, widespread interoperability in the voice-over-IP marketplace doesn't yet exist. Until this interoperability is proven in the public domain, all of the gains voice-over-IP products have made in the past year will be bridled by the fact that making an end-to-end call using this technology is probably not going to work.

This story, "Interoperability affects booming VoIP marketplace" was originally published by Network World.

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