Expert warns of impediments to VoIP
Expert warns of impediments to VoIP
Many organisations adopting Voice over IP (VoIP) technology aren’t considering the technology’s full potential impact on the network infrastructure, a leading technology consultant has warned.
Speaking at this week’s Damovo04 conference, Gary Audin, an independent consultant and 40-year telecommunications veteran who is president of US-based Delphi, Inc., recounted the experience of a customer who wanted to implement 1800 VoIP handsets. Plans were changed after being advised that installing adequate cabling, patch panels, air conditioning for telephony closets and other necessary infrastructure improvements equipment would cost US$500,000 before the first handset was plugged in.
Audin believes the industry still has a lot of work to do before VoIP technology compares with existing switched networks. While the handsets are robust, for example, they interface with controlling software that falls far short of the ‘five 9s’ – 99.999% availability – required to match the stability of conventional telephones.
Many data vendors treat IP PABXes like computers, issuing regular patches to improve stability and security – an unacceptable practice in the telecommunications world. “One of my clients has a six-hour period of downtime every four weeks that he spends just doing patches on the VoIP system,” Audin says. Even worse, patches sometimes break old functionality.
Other problems include difficulties integrating VoIP with proprietary digital handsets; the relative lack of features in products from data-turned-VoIP vendors like Cisco Systems, compared with those from voice-turned-VoIP vendors like Mitel and NEC; and stability issues introduced with ‘soft phone’ applications dependent on the underlying operating system.
Customers also carry some of the responsibility for VoIP technical problems. Audin cites capacity planning as a priority: although voice compression protocols like H.323, G.711 and the newer G.722 shrink voice into between 3 and 7 Kbps, protocol overhead bloats these streams to consume 24 to 28Kbps of bandwidth.
Multiply this by the number of handsets and add existing data volumes, and you’ve got to reconsider network capacity. “All problems except errors are congestion related,” said Audin. “Peaks and valleys will change the quality of the call.”
As Audin’s customer found, the high cost of infrastructure can be a surprise. But there are ways of reducing this: for example, ignore the arbitrary goal of moving every phone to VoIP; running VoIP to the janitor’s closet costs more than it’s worth.
Another cost-saver is Power over Ethernet (PoE), which delivers DC power to VoIP phones via existing data cabling. “Think of it as a long-term utility investment,” Audin said. “You’re going to put other devices – wireless access points, Bluetooth devices, surveillance cameras and so on – onto the network in the future. This changes the cost of deployment as well.”
Cabling is another sticking point: Ethernet, running over Category 5 data cabling, runs into trouble over lengths of cabling that are more than 100m long, compared with the 1000m acceptable to conventional telephony.
These issues may seem small, but they’ve tipped the conventional technology adoption model on its head. IT systems usually debut at large companies with the capital to buy them, then make their way into smaller accounts as the technology improves and cheapens. VoIP, however, is starting small and trying to grow from there – forcing vendors to drop prices and increase modularity to suit small business customers.
Big business is still biding its time, Audin said: “We’re still finding that large corporations aren’t ready to commit the whole corporation. Very few companies are actually installing over 1000 handsets. And even if they’re thinking about commitment, they may do an office a week. The whole rollout might take two to three years.”
There is hope, however, for broader VoIP uptake with increasing support for SIP (Session Initiation Protocol), which replaces incumbent but bulky standard H.323 with an open framework that’s more modular and easier to integrate with new applications. SIP, along with the new high-quality G.722 audio compression standard, will combine to produce innovative telephony systems that facilitate high-quality collaborative interaction between on and offline parties. And that, Audin believes, is when the VoIP market will gain long-overdue momentum.
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