Enterprise VoIP Solutions

Not long ago, Cisco Systems dominated the VoIP market, thanks to its 1998 purchase of Selsius. Legacy providers were thrown off guard initially, but the tide is quickly turning. One Dell'Oro market share report (see chart below) shows Avaya leading Cisco in large IP PBX shipments in the third quarter of 2004, with Nortel Networks a close third. Even more significant, this tally doesn't take into account hybrid systems from Avaya and Nortel that combine TDM (time-division multiplexing) and VoIP ports. There are many smaller players to choose from as well, including Zultys Technologies and Vonexus, which both participated in our review. Although cost is cited in our reader poll as the No. 1 obstacle to VoIP adoption (with the need to upgrade networks a close second), competition shows no signs of cooling, and that's good news for consumers.

Standard and Deliver

Standards like Ethernet, IP, PoE (Power over Ethernet) and QoS (quality of service) let you plug all components of a VoIP system into any other vendor's data network, which means you can shop around for the best price.

Moreover, the SIP (Session Initiation Protocol) standard makes it feasible to choose different vendors' gateways for access to the PSTN, with SIP trunking between the gateway and the IP PBX. SIP is currently an approved draft standard; some advanced features are still under construction, but many vendors are finding ways to make it work.

SIP also makes it possible to integrate presence applications from different vendors, as well as use phones from one with the IP PBX of another. Many vendors have resisted this--after all, half their revenue comes from phones.

For our review (see "Live in the Labs: IP PBXs," ), we required that vendors spec out third-party phones and be prepared to demonstrate interoperability with three different vendors' endpoints. We tested some advanced features, and though the results weren't perfect, we believe SIP is a viable protocol for multivendor, enterprise IP-PBX phones. Despite some interoperability problems, we were impressed that Vonexus requires third-party SIP phones and Zultys uses only SIP phones. We were also pleased that Avaya has an extensive certification process for third-party SIP support and has demonstrated a commitment to making it work.

This is another advantage that Avaya has over its rival Cisco. Although Cisco has support for SIP trunking in its CallManager product, you can't buy SIP-based phones from a third party that will work with Cisco's CallManager. We hope that changes. Even though Avaya has a third-party certification program, it does not sell third-party phones, although we hope that will also change in the future. No matter how you cut it, we recommend making third-party SIP support a requirement.

Don't recklessly crash the VoIP party, however--as with any technology decision, you shouldn't make a move just because you think everyone is doing it (they aren't) or because of vague ROI claims. Yes, VoIP has matured significantly and deserves serious consideration, whether as a PBX replacement, for trunks between office locations or to enable new presence-based services. But if your old PBX is humming along and supporting the communications needs of your business, maybe VoIP isn't justified. In our reader poll, 11 percent of respondents said they have no plans for production-level VoIP because their current PBXs work just fine.Of course, you should still talk to salespeople and lay the groundwork for a VoIP pilot. Determine whether you have the skills in-house to manage the new technology and deal with new security problems. One note: The 10 percent of readers with security concerns should check out a free, 99-page report by the National Institute of Standards and Technology (NIST) titled "Security Considerations for Voice Over IP Systems," available at csrc.nist.gov/ publications/ nistpubs/ 800-58/SP800-58-final.pdf.

Before building a purchasing proposal, evaluate your infrastructure to ensure that your network can handle VoIP (see "Prepare Your Network for VoIP,"). If you lack QoS and high availability, it could be tough going. In that case, a phased approach may be in order.

Determine the optimum mix of TDM and VoIP for your network. For example, VoIP could be used to trunk together legacy PBXs. It's also possible to have one PBX support a mix of VoIP and TDM phones. Some vendors, notably Cisco, will push you toward pure IP simply because that's what they sell, while legacy PBX vendors like Avaya take a different approach, placing no real limitations on the number of TDM phones in the mix. In fact, if you own an Avaya PBX, you may be able to add VoIP functionality and start reaping the benefits without a forklift upgrade. Many legacy vendors also offer pure IP systems backed by a long track record of providing solid voice services.

Prime VoIP candidates are companies with many, geographically dispersed offices. VoIP can trunk locations together over existing data WAN circuits, saving on long-distance while making more efficient use of bandwidth and improving intracompany communications. It also provides some flexibility in PBXs locations. For example, some locations could have only VoIP phones, accessing a PBX at another location. Keep in mind that in some cases, VoIP calls can take up more bandwidth than corresponding circuit-switched calls, depending on the type of codec used (for more on codecs, see the "VoIP Codecs" sidebar). In our reader poll, about three-fourths of those installing VoIP weren't sure which codec they were using! Another benefit that VoIP provides for those with physically dispersed locations is the opportunity to easily consolidate multiple vendors' PBX systems, cutting maintenance costs.

Redmond's SIP StakeMicrosoft was an early adopter of SIP; for example, with Microsoft Office 2003 applications, it's possible to pass along presence information with document attachments. This functionality does require at the back end Microsoft's LCS (Live Communications Server), which includes SIP and presence capabilities.

And Microsoft says its new desktop initiative, Istanbul, due for release later this year, will include even richer presence, video and phone capabilities, offering integration with SIP phones and IP PBXs, as well as Microsoft Desktop applications (see "Siemens Also to Support Istanbul Directly,"). For now, Microsoft is partnering with Alcatel, Mitel and Siemens to integrate their VoIP phone systems more closely with Windows, and it's working with Polycom to integrate phones and videoconferencing solutions.

It remains to be seen how much interoperability there will be between Microsoft and the rest of the world--in the past, the company has removed SIP functionality from some desktop applications without warning, notably Windows Messenger. Still, there are many advantages to integrating desktop apps with communications services, and this is an area we'll be keeping an eye on.

One Voice On Feb. 7, the National Institute of Standards and Technology (NIST), Purdue University's Cerias Lab, Symantec, Qualys, Alcatel, 3Com, Enterasys, Spirent Communications, Qwest and Comcast joined with TippingPoint to form the Voice Over Internet Protocol Security Alliance. The group says it will work with such organizations as the IETF and SIP (Session Initiation Protocol) Forum to publicize possible vulnerabilities in VoIP networks and ways to counter emerging threats.

Peter Morrissey is a full-time faculty member of Syracuse University's School of Information Studies, and a contributing editor and columnist for Network Computing. Write to him at [email protected].Our "Join the Party" theme implies that you'll have a rollicking good time implementing voice over IP. Admittedly, that's a stretch, but not as much of one as you might think.

First, competition among vendors is fierce. You have your pure-play IP PBX sellers and your conventional PBX vendors that have expanded to include pure-IP and hybrid offerings. Any time you can get three or four viable RFP responses, that's a good thing.

Second, the SIP (Session Initiation Protocol) standard is nearing completion. Indeed, the PBXs and third-party endpoints in our tests proved more interoperable than we'd expected.

Finally, VoIP enables new features that will make end users and telecom managers alike toot their party horns; these include unified messaging, simpler moves/adds/changes, more geographic flexibility, easier integration with new applications like presence, and soft phones that add features and help manage desk phones. All these should help you make your case for the technology investment, and maybe even a supporting network upgrade.

In "Live in the Labs: IP PBXs,", we report on testing IP PBXs from Avaya, Vonexus and Zultys Technologies in our Syracuse University Real-World Labs®. In addition, we updated our RFP on behalf of fictional underwriter HaveNoFear Insurance and factored that into our scoring. Avaya's IP Telephony Solution took our Editor's Choice award because it provided the best interoperability, comprehensive management tools and a ton of features for the price.