In the second of a two-part interview with vnunet.com, Cisco chief technology officer Charles Giancarlo discusses how he sees consumers moving to Wi-Fi phones that offer broadband services in addition to voice telephony.

Giancarlo elaborated on what his company has in store for the enterprise, and why Cisco has been relatively quiet about Session Initiation Protocol (SIP).

SIP is an industry standard, backed by Cisco, Nortel Networks, Microsoft and others, designed to move communications with the user. In essence SIP is like having a single telephone number for a landline, mobile phone, instant messaging and email.

The protocol makes sure that communications get routed to the appropriate medium: in the office a call will be connected to a user's phone, when in a meeting communications will be forwarded to a voice mail box or instant messaging and when traveling callers get a mobile phone.

Enterprises have traditionally invested in VoIP for new offices. What is going to make them switch to VoIP more quickly?

We shipped over two million VoIP phones last year. That is accelerating quite dramatically. If you look at new systems shipped, VoIP is now well over 50 per cent of the market for new systems.

I don't know if we need to ask what is the killer app any more. The enterprises are moving toward it. It is the next-generation system and the enterprises know that.

The reasons why enterprises are buying now are varied and many. The two major ones are the ability to consolidate branch office environments, so you have fewer instances of the PBX and you dramatically lower operating costs. The second is much lower move out and change costs. So that is ROI-based.

As we go forward, it's going to be based much more on improved collaboration capability with VoIP. It's not just an issue of the phone, but the ability to have a rich media client on the PC to be able to do collaboration: video, voice and desktop applications such as sharing documents, videos, PowerPoint presentations. As well as unified messaging, being able to access your email and voice mail while you are on the road.

And this will all use SIP?

Increasingly we'll move more toward SIP. But SIP is still relatively immature at this point.

Cisco seems to be behind its competitors with SIP

We have more SIP clients deployed than any other vendor. We have more SIP proxy servers deployed than any other vendor. There are lot of other vendors that are talking about SIP for their future products, or use SIP purely as an encapsulation protocol underneath. We are the ones that have not only created the SIP standard, but deployed more true SIP environments than any other.

You're not talking about it because you think it's too far out?

We've taken criticism in the past in other areas where we try to portray a realistic environment for some of these new protocols. We try to be very realistic about SIP in terms of what it can and can't do. Because we haven't over-hyped SIP, our competitors are saying: 'You see, Cisco is not SIP.'

We have more clients deployed than anyone else. We are very supportive of SIP, but we didn't want to kid customers two or three years ago by saying that you could deploy SIP, that SIP at that time was ready for full deployment in a complex environment. It made great demo systems, which is different from being ready for full scale. But we are getting much closer to a world now where SIP is a viable protocol to use in more complex environments.

The majority of what Linksys now ships is SIP-enabled. All of the call managers that we ship today have fully functional SIP trunks. The difference between a SIP trunk and a SIP line is that a SIP trunk is used for application integration.

The SIP control application would work through that SIP trunk. One of the reasons why we decided to build that SIP trunk before the SIP line is that the customers will tell you that they want to integrate applications.

We'd like to have an application environment where we have greater levels of integration. One might ask what is the use of SIP to the phones. SIP to the phone is something that we are working on. We do have SIP working for service provider environments. We'll have that as well for call manager environments but the customer benefit of that is somewhat less.

Click here for part one of this interview.