Mobile VoIP services have yet to make their mark on the telecoms market, despite the availability of suitable technology.
Barriers to adoption might leave services languishing, at least until the rollout of next-generation mobile networks by carriers, according to panelists at a debate on the topic at the NetEvents summit in Malta last week.
Emir Halilovic, programme manager of networking and infrastructure at analysts IDC, said VoIP remains predominantly a fixed-line market. Multimedia revenues in the mobile arena are growing quickly, but from a very small base.
"Mobile applications are a very, very small slice of that whole market. Still, there is a great promise in both [mobile VoIP and multi-media] because the ecosystem elements are all there, although it's still not fully functional."
Connecting existing GSM or 3G Radio Access Networks to VoIP systems would bring the cost and feature benefits of VoIP to all those handsets. VoIP on mobile networks also offers spectrum usage benefits to operators.
But the technology competes against offering comparable services over Wi-Fi networks. Wi-Fi-based services require new multimode handsets, client software, and significant investments in upgrading existing wireless networks. Since providers are doing all these things already this is not the show-stopper it might seem. Ingrained user behaviour is more of a problem.
Dean Bubley, founder of Disruptive Analysis, said the market for conventional voice calls remains healthy. "Ordinary GSM cellular is not going to go away any time soon, particularly for the 60 to 70 per cent of mobile subscribers who are prepaid customers and more particularly for those who don't have access to broadband.
"Although Wi-Fi and dual-mode devices are becoming available in wider numbers they are not used by many people for VoIP. There's some traction in enterprise which has been pretty slow coming. Certainly we're not going to see double-digit percentages of the global subscriber base using VoIP on wireless LANs.
"I'm a huge disbeliever in metro Wi-Fi for VoIP simply because the external Wi-Fi doesn't penetrate into building, so it's pretty much useless for the majority of calls."
Bubley was far more positive about the use of 3.5 and 4G networks as a platform for VoIP, saying the "next generation of mobile networks are designed for VoIP".
Those with a favourable flat-rate tarriff can run VoIP over a 3G connection, providing they don't run foul of their terms and conditions - but this will remain out of the ordinary for the next few years. VoIP on wireless networks is constrained by quality of service and coverage issues.
"I think through that in five years you will have more people using Voice-over-3G network than using it with Wi-Fi. But both of those numbers will remain dwarfed by people just using circuit-to-cellular," Bubley added.
Michael Coci, product marketing director at wireless switch vendor Trapeze Networks, said putting extra traffic onto wireless LANs was a viable strategy, at least for enterprises. "In the enterprise environment you have a much deeper amount of control over the RF environment, over the handset, over the quality of service. And in the environment it's absolutely a viable, and in fact, ultimately for a better solution than Voice-over-3G."
IDC's Halilovic concluded: "It's is our firm belief that all voice will be eventually be transferred over IP. Whether it is going to be in our lifetimes, is open to debate." ®