Don Proctor, general manager of Cisco's Voice Technology Group spoke with Network World Senior Writer Phil Hochmuth about why businesses should invest in IP telephony and about Cisco's voice road map.Don Proctor, vice president and general manager of\u00a0Cisco's Voice Technology Group, is responsible for the direction of the company's convergence products and strategy. Last month at the VoiceCon show in Washington, D.C., Proctor spoke with Network World Senior Writer\u00a0Phil Hochmuth\u00a0about why businesses should invest in IP telephony and about Cisco's voice road map.What is the return-on-investment case for IP telephony?ROI is the thing that matters most right now. . . . While the ROI that can result in a 10% decrease in IT staff costs [as a result of simplified adds, moves and changes with IP telephony] can be a good business decision, it's also very interesting to look at the ROI that could be achieved by just a 2% increase in the productivity of end users. The notion here is that total-cost-of-ownership [TCO] savings has become table stakes.This boils down to measuring infrastructure investment. This includes TCO, of course, but it also [includes] looking at things like . . . How can you get better asset efficiency on what you already have in place today? What's the value in your company of preserving multiple options in the future? Should your business be in some state of transition?While small and midsize firms are using IP telephony more, what are the barriers for widespread rollout in larger companies?People are still getting comfortable with the technology. One of the biggest barriers to deployment today comes down to a skills issues in many cases. [Customers] are still building the experience level and skill level to be comfortable with [IP telephony]. People who come from a traditional voice background may feel they are facing a number of unknowns. In most cases, [traditional voice] professionals don't realize how much of their voice experience can be leveraged in this new world of converged networks.For our part, Cisco will be introducing a new professional certification program focused specially on IP telephony. When I talk to customers about the divide between traditional voice background and the IP telephony background, many don't realize that [approximately] 54% of the engineers who build voice products at Cisco come from a traditional voice world.Many competitors are migrating from Windows-based servers toward Linux and real-time operating systems for their IP BX products. Are any changes on the horizon for the Cisco CallManager IP PBX software, which is Windows-based?We've got customers who are passionate in both of those camps [Windows- and Linux-based IP PBXs]. We have customers who are very committed to Windows as their enterprise application infrastructure and are going to stay with it. We also have some customers who would prefer a Linux-based appliance model for an IP PBX, and it is likely that we will have future variants of CallManager that are based on that model.Are there advantages in having one or the other?The consensus is that [there isn't] . . . We have an architecture we've built around [IP telephony] security that we call SAFE - the SAFE architecture for IP telephony, which includes components like intrusion detection, firewalling, encryption, authentication, all the factors that make up good net hygiene. This architecture can be applied to secure any type of system [whether it be Windows, Linux or Unix].If securing IP PBXs is the same as securing other application servers, how should users secure the voice traffic itself?The typical case is that people use some kind of VPN application. The softphone is a good example. When I'm in a hotel that has a broadband connection, what I do is connect to the network and start my VPN client, get my encrypted secure tunnel to the Cisco network. Then I start the softphone, [and] then I'm able to get the same voice services that I have in the office. That model is the one we do most typically.Is it the most efficient?It certainly delivers the right combination of convenience and privacy. Is it the most efficient? Well, you have a tunnel, so there's an extra header on there, but as a practical matter, it isn't a huge issue.What are Cisco's plans to support Session Initiation Protocol [SIP] natively on CallManager?Certainly SIP has a very vocal following. I'm bullish on SIP. I think it holds a lot of promise for the industry . . . . We [probably] ship more SIP [products] than any other vendor with our [phones, softswitches, SIP-enabled firewalls and gateways]. We will have more SIP functionality coming into more products over time. The real promise comes with embracing what I call the Tao of SIP, and that is not only embracing the protocol, but accommodating that sort of fully distributed paradigm of the sip architecture. . . . We will see a SIP-based call manager [soon].IP telephony vendors, including Cisco, are starting to offer solutions for running voice over 802.11 technology; are you seeing any customer interest in Wi-Fi IP telephony?Absolutely. It's the same value proposition that people see in Wi-Fi for data networking - mobility in a campus environment and the ability to have your communications portal wherever you are, irrespective of location. Its not uncommon around Cisco offices - and admittedly we are a bunch of geeks - to see people walking around with [Compaq iPaq PDAs] with 802.11 cards, running our softphone software. When someone gets a call, their iPaq rings.Do the network challenges associated with 802.11 - such as security or the fact that it's a shared network - become compounded when putting voice over Wi-Fi?The fundamental issues are the same issues we face when transmitting data [with Wi-Fi]; you've got to have authentication, and you've got to have privacy. . . . Stay tuned for more on that topic. We're very interested in this kind of marriage of Wi-Fi and IP telephony.Cisco works with handset makers in the Wi-Fi market, such as Spectralink and Symbol. Are you looking to expand those kind of relationships with other handset makers or release your Wi-Fi IP telephony handset?All I can say at the moment is, stay tuned for more news there.