For years we've heard how voice over IP is the future, ushering in a new paradigm of openness never imagined by the tired, proprietary TDM-based phone systems it was destined to supplant. In reality, though VoIP phones certainly appeared innovative, many carried the same baggage as the legacy phones they replaced. And in some cases they were a lot more expensive and just as proprietary. In fact, you were stuck buying all the components of a VoIP system from one vendor. At least with legacy PBX phone systems, you could pick up cheap analog phones compatible with any PBX.
The two biggest excuses offered by vendors to justify locking customers into this proprietary hell have been that standards-based products weren't mature and the industry hadn't yet agreed on what standard to use. Indeed, today you can buy phones based on three different standards: MGCP (Media Gateway Control Protocol), H.323 and SIP (Session Initiation Protocol).
All have merits, and we could argue at length about which is technically superior. But it's clear to us that the competition is over, and the winner is SIP (see "SIP Packs a Punch"). After testing six SIP phones, we feel it's safe to say that SIP for VoIP phones is mature and solid. Those vendors claiming there isn't a viable standard for VoIP phones have just run out of excuses.
Call Center
We set up a test network in our Syracuse University Real-World Labs® (see "How We Tested SIP Phone Interoperability,") and put SIP phones from ipDialog, Mitel Networks, Polycom, Siemens, Snom Technology and Zultys Technologies through their paces. Each provided solid SIP IP connectivity. We probably would have gotten even more participants if we hadn't been so picky. We required each phone to have two Ethernet ports, a speakerphone and support for the IEEE 802.3af PoE (Power over Ethernet) standard. We were looking for a standards-based business-class device able to support a phone and a PC, and provide power to the phone, all from one cable drop. The IEEE 802.3af standard was finalized in June and started to solidify long before that, giving vendors plenty of time to incorporate PoE into their products.
Besides the six participating vendors, we invited Alcatel, Avaya, Cisco Systems, Nortel Networks, Pingtel and 3Com. Alcatel told us it does not make a SIP phone, though it does provide SIP functionality in its OmniPCX Enterprise PBX. Pingtel is an early adopter of SIP with its Expressa product. In fact, Pingtel's phones were used at The Hotel Commonwealth, Boston, where the company partnered with Alcatel (see "SIP Shows Some Hospitality,"). However, Pingtel's phones didn't meet our requirement for two Ethernet ports, though the company did say it would have a product with those ports by September. 3Com said it was anxious to participate, but didn't have a product meeting our requirements ready in time for our tests. We never got definitive answers from the others on why they didn't want to play.
We used BroadSoft's BroadWorks SIP services for our testing. This gave us the opportunity to partner with a leading SIP vendor for a reference platform for interoperability testing. BroadSoft employs a B2BUA (back-to-back user agent) for SIP signaling, meaning the proxy server stays available throughout the call and also for the termination of the call. Without B2BUA, the proxy server would drop out of the picture once the initial connection was completed. With B2BUA, we gained centralized tracking of the call for call-detail recording.
REPORTS
Analyize In-Line NAC strategies and products.
ANALYTICS Plan and design your enterprise blade server deployments
InformationWeek U.S. IT Salary Survey 2008
Salaries for business technology professionals are falling. Here's what you need to know in order to make good hiring decisions and personal career choices. Purchase Today: $299
REPORTS
ANALYTICS
Follow 
