Two very different people, from vastly different backgrounds, described two virtually identical ways of working at the VON show for VoIP in the UK, both appealing, but very different in price, technology and approach.

And the key to the future of voice over IP, is perhaps in knowing which one is right.

It may shock you to hear that one was the irrepressible techie upstart Niklas Zennstrom, author of Kazaa, and co-founder of Skype, while the other was Brian Day, a senior figure within Nortel's hosting services division.

Perhaps the experience they are preaching is about the only thing they have in common.

At the heart of this divide is the fact that they both think that VoIP is something completely different from what the other believes.

Zennstrom says that voice over IP is just a PC application, it's not a network, it will not replace what the community fondly calls POTS (plain old telephone system), it does not need regulating, there is no monopoly in it and it's not really telephony. It's just, as he says, a PC application.

CHANGED WAY OF WORKING

Day already lives in a world where he is helping both wireless and wireline telcos make more money and reduce churn. He preaches his company's hosted systems and said, "My own personal way of working has changed beyond all recognition using these systems, and hosted services, including VoIP, is one of those things that once you've worked with it, you suddenly can't live without."

Day went on to describe how once he was headquarters bound and fixed to a single desk and that the mobile phone only partially released him from this, but now he takes his office with him everywhere.

"I can work from a hotspot, from a regional office, from home, I can be Wi-Fi connected or connected through a hotel broadband line and everything's the same. I can talk to my staff, see them on video, I can detect their presence, email or instant message them. I can explain things using co-operative browsing. It's just like being in my office," said Day.

But Day was evangelising the big corporate vision, something that Zennstrom tended to avoid later that afternoon. And yet Skype looks increasingly like the Nortel hosted tools that Day was talking about. It has pictures now, videoconferencing in the near future, if offers presence through IM, and VoIP calls that beat mobile phones for quality easily, and, when they don't suddenly drop out, approach or beat fixed line voice quality. It comes with buddy lists, and will shortly have whiteboarding and text messaging and its own API for third party add-ons.

You can work on Skype in just the same way that you work on the Nortel system and on many other corporately targeted systems, but there are differences.

You don't have anyone you can call if Skype doesn't work, apart from the handful of geniuses that work at Skype. With an enterprise VoIP set-up you can have someone look at your routers, do an examination of your network, check for incompatibilities between your SIP (session initiation protocol) clients, and your firewall or NAT server.

Your Softswitch, a server that acts like a VoIP PBX, might need configuring and you may have interference from outside your network and perhaps the policy on your session boarder controller, a multi gigabits per second device, might need adjustment.

The corporate version of voice over IP, and all the digital additions to telephony that can be added around VoIP, is indeed complex. It needs to be secure from attack. For instance, what's the difference between an unsolicited email, and a phone call? And yet not only do you want an unsolicited phone call from a new prospect to get into the network, you want it treated with priority.

BORDER CONTROLLERS

But how does your network know that a voice call on VoIP doesn't contain a virus if it bypasses the firewall? Hence the border controllers that are becoming fashionable from companies like Nortel, but also Netrake, ACME, 3Com, Sonus and a host of others that are all members of the SIP way of doing things in the corporate world.

And similarly how do you bridge in and out of an enterprise that still has legacy telephony systems side by side with new VoIP systems? Here more gateways are needed.

Zennstrom says he has the answer: don't use SIP at all "because it is a badly written protocol and it just doesn't work." Well that's a bit strong given that the entire VoIP industry has been built around it. What Zennstrom really means is that SIP doesn't work first time on every network and has trouble traversing firewalls and especially NAT servers.

In other words, someone who understands networks has to make sure that your network is set up to recognize and receive VoIP packets and route them appropriately. And that, for the most part, includes more expensive, specialized hardware.

In fact, this is really part of the Nortel message to operators everywhere, replace declining voice revenues, and those being lost to wireless telephony by offering managed and hosted services. Day says he has seen ARPU (average revenue per user) figures as high as $300 to $600, and on this basis the systems that he was pushing show a payback in under 18 months. Effectively, he sees his role as helping to stop the operators go out of business.