Virtual network operator Sirocom is moving into voice services as well as data. Sirocom CTO David Macfarlane told Techworld he believes voice, especially with the rush of voice-over-IP, is now ready for the same sort of managed network provision that has already benefited data customers.

The VNO model relies on a number of factors. One is that the VNO acts as an aggregator, buying data services wholesale from telcos and then selling them on to its customers in combinations that the telcos cannot themselves offer. Another is scale - because the VNO buys so much capacity from its telco suppliers, it can negotiate bigger discounts.

Macfarlane said Sirocom is now ready to do the same with voice services via a three-stage process. In the first stage, companies would converge their voice service usage into a single bill across all their offices, in the second they would start bringing in VoIP and migrate as much traffic as possible onto IP, and in the third, they would move to full IP telephony via a Sirocom-hosted call manager.

Industry observers were initially sceptical, pointing out that voice services are still much more diverse than data, whether they be traditional TDM services or emerging VoIP offerings, which have still not consolidated on SIP, despite predictions. "There's lots of proprietary stuff out there," said one. "Data networks are pretty standard these days, VoIP adds a layer of uncertainty."

But Macfarlane said the company already has early users for the scheme. He claimed that in tests with beta customers, the annual savings for the initial spend-convergence stage alone averaged more than 25 percent.

He added that similar savings are possible from stages two and three because of the consolidation they involve. "Enterprise comms managers whinge about fixed-to-mobile rates but they forget some easy wins," he said. "They don't know their fixed rates, or how many free ISDN-30s they've got." He said shifting traffic onto IP means branch offices require fewer dedicated - and expensive - PSTN lines, for example.

Offering the example of an unnamed beta customer for the service which has 54 offices, he said stage one saved the company over £120,000 - around 20 percent - partly because it had been paying 1.9p/min for calls compared to Sirocom's rate of 1.1p/min, and partly because it moved to wholesale line rental from an alternative carrier.

"In phase three, we hosted a call manager in our core and shut down most of their branch ISDNs," he added. "Now each branch has an SDH MPLS line with DSL backup and voice goes directly into the PSTN via IP. They have 40 percent less channels for phone calls than a year ago, because of the centralised solution." That saved another 20 percent overall, he said.

"It's a convergence strategy, we've not just trying to sell voice," he admitted. "But if you can't converge your networks, you can at least converge your spend."