As the key VoIP equipment supplier to the carriers leading the VoIP charge, Sonus Networks has both an enviable market position and an interesting perspective on the migration to the world of packetized voice.The nation's core telecom infrastructure, says Sonus Chairman and CEO Hassan Ahmed, is updated on a 25-year cycle, the last great wave having been the move to digital switching. By his calculation, we are now in year five of the next big wave, the migration to VoIP.Early VoIP adopters did so in the core, a fact that helped Sonus succeed where other upstarts failed. "We focused on Class 4," Ahmed says. "Everyone else was betting on Class 5, the edge. The reality was you had to packetize the core before the edge."Today the company's customer portfolio includes AOL, AT&T, Bell South, Cingular, Verizon and Vonage. Ahmed figures that VoIP networks built using Sonus gear carry some 17 billion VoIP minutes per month."With the migration to packets over broadband, connectivity to the network is disaggregated from the services delivered," Ahmed says. "In the old world, the switch that terminated the copper pairs also provided the service. Now you can terminate the last mile in Manhattan and offer service from Kansas."Although early carrier converts brought in VoIP to reduce costs, the name of the game today is advanced services. "The last five to six years was about converging nets for operations savings," Ahmed says. "Now it is about new services."If you use Verizon for phone service, Internet access, cable TV and cellular support, he argues, you want the network to support your every whim. "If I'm on a train to New York and want to watch CNN on my cell phone, the net should know who I am, where I am, and deliver what I want in a presentation format required by the device I'm using."Sonus calls that "service convergence," and Ahmed expects to see it start to take off in the next three to five years. But it can't happen until the wireless carriers finish building out broadband support. Those efforts have begun, but it will be a few years before there is widespread availability of multi-megabit cellular data links.The fatter pipes will make it easier to offer new services, and that in turn will provide incentives for the wireless carriers to move to IP, Ahmed says. He sees wireless moving to IP switching beginning in 2007."The way we view it, the future is about Session Initiation Protocol-based services sitting on top of broadband wireline and wireless infrastructures" and customers being able to move between them seamlessly, Ahmed says.It is a compelling vision.