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WiFi Telephony: Back to the Future

By Ben Guderian


It�s time to take a look at how far we�ve come in the relatively young life of WiFi (News - Alert) telephony and assess the progress made in terms of the technology and market adoption. Much of the development has been influenced by standards (or lack thereof), along with the typical growing pains associated with deploying any new technology. We�ve experienced hot enterprise markets, such as healthcare and retail, and we�re now seeing the emergence of WiFi telephony applications targeted at the consumer. As we look toward the future, it�s clear that both IP telephony and WiFi are here to stay. The synergies between them will have a significant impact on communications both inside and outside the workplace.

Looking back on the history of WiFi can tell us a lot about the future. With the ratification of the initial 802.11 wireless LAN standard in 1997, enterprise wireless data technology went from proprietary implementations serving niche applications, to widespread implementations by leading data network vendors. About the same time standards-based, interoperable wireless LANs hit the market, we began seeing viable and practical implementations of enterprise IP telephony. The initial challenges of running voice applications over wired IP networks � performance, security, and QoS � were amplified when dealing with wireless networks. And while most enterprise IP telephony solutions carried the PBX tradition of keeping telephone sets and protocols proprietary, interoperability and standards compliance were baseline requirements for wireless networks and client devices.

The initial driver for enterprise WiFi telephony was employee mobility. Most of the early deployments were in healthcare, big-box retail, and manufacturing applications. Return on investment was based on providing critical employees, such as nurses, department heads, and technicians, with telephone access while on the move. Although other wireless technologies, like pagers, walkie-talkies, and cellular phones, were viewed as alternatives, none offered the telephone system functionality and network reliability provided by WiFi telephony.

In many situations the business case for deploying a WiFi network was driven primarily by the requirement for mobile telephony, with mobile data support as a secondary benefit. Alternatively, some enterprises made the case for deploying WiFi based on data application requirements, and then leveraged the same infrastructure for voice. For example, in the hospitality market, many hotels deploy WiFi to provide guests with broadband Internet access for WiFi-enabled laptops. With the WiFi network in place, adding WiFi telephones for the hotel management and staff means lower cost, higher functionality wireless communications, enabling greater response times and higher productivity.

Standards to the Rescue
While concerns about WiFi security and voice/data convergence still linger, the clear trend is toward WiFi. WiFi infrastructure has come a long way in the last five years, with much of the innovation focused on providing higher quality voice applications. Security has been addressed with the IEEE 802.11i standard and the WiFi Alliance WPA and WPA2 specifications, which have all undergone extensive industry scrutiny to verify their suitability for enterprise applications. There are still some security improvements in the works, specifically the 802.11r standard for improving roaming without making compromises on security. Other security requirements have been met through implementing virtual private network (VPN) solutions.

From the very beginning, quality of service (QoS) for WiFi telephony has been a critical need. QoS is important for any IP telephony implementation, but even more critical with WiFi telephony because of the limited bandwidth. Shortly after the initial standard was ratified, the IEEE commissioned the 802.11e task group to develop a standard. Early entrants into the WiFi telephony market had to develop stop-gap QoS mechanisms. Fortunately these solutions allowed the market to develop and validated the necessity for enterprise-grade QoS. The 802.11e standard was ratified in 2005 and the WiFi Alliance is now rolling out its WMM specifications for QoS components in enterprise WiFi telephony.

The most tangible and publicized WiFi innovations have been the evolving standards for higher data rates. The initial 802.11 standard had a maximum data rate of 2 Mb/s. Then came 802.11b, speeding things up to 11 Mb/s, shortly followed by 802.11a and 802.11g running up to 54 Mb/s. Now we�re anticipating the 802.11n standard with potential for rates in excess of 300 Mb/s.

Most WiFi telephony devices still use 802.11b and haven�t kept up with the race for higher speeds for a couple of reasons. First, most enterprise WiFi implementations use 802.11b as a lowest common denominator, which means they may support 802.11g and/or 802.11a speeds, but they still need to provide backward compatibility for older client devices using 802.11b. The second reason is that voice applications don�t benefit from faster data rates the way data applications do. Higher data rates translate into higher user density for voice applications, but the vast majority of enterprise applications can be served today by 802.11b. Over time, 802.11b will be phased out as WiFi devices migrate to support 802.11a and 802.11g and, eventually, 802.11n, depending on its adoption in enterprise applications.

The missing link on the standards front has been the lack of enterprise VoIP protocol standardization. While the WiFi industry has invested significant time and energy into standards and specifications to ensure interoperability and multi-vendor solutions, the enterprise IP telephony market has remained predominantly proprietary and closed. Even though it�s clear that SIP has prevailed as the open standard of choice for VoIP, most enterprise IP telephony solutions continue to utilize proprietary protocols as a means to deliver advanced features and capabilities.

The Device Landscape
More devices are coming to market to support WiFi telephony applications, and in this area we see divergence between consumer-focused and enterprise-focused products and services. On the consumer side, we�ve seen WiFi handsets offered for accessing VoIP services such as Vonage (News - Alert) and Skype (News - Alert), with some even bundled by VoIP service providers. These handsets are designed for use on home or hotspot WiFi networks, so they don�t typically support enterprise-grade security, QoS, and roaming capabilities. Another category of devices are handhelds which incorporate both cellular and WiFi radios in a single device. These dual mode devices let the user take advantage of high-speed connectivity primarily for Web surfing and e-mail synchronization using WiFi networks, but some are also capable of running softphone applications to support telephony over WiFi networks.

Dual mode devices offer the advantage of having a single handset for ubiquitous use. Consumer-oriented dual mode services, such as British Telecom�s Fusion, give customers a single handset to use as a cordless phone over WiFi at home, and a GSM cellular phone away from home. Similar applications are targeted at enterprise customers, although they carry the additional challenge of integrating with an enterprise PBX to deliver business telephone features in the office. Offering the ability to hand off calls between the WiFi and cellular networks is seen as a key benefit for dual mode applications, and various carrier-based and enterprise-based solutions are available today or coming soon.

However, dual mode handsets aren�t for everyone. Just as laptop PCs haven�t completely displaced desktop PCs, there is still a large number of employees that only need work-related telephone access at work. Employees who don�t travel or need to be accessible during off-hours can be given WiFi devices that stay in the workplace and avoid the additional cost and management issues associated with cellular services. On the other hand, employees that are furnished with cellular phones for off-site calls are the most likely targets for dual mode handsets.

Looking Ahead
As we look to the future of WiFi telephony, there are some easy predictions to make. Penetration of enterprise WiFi technology will continue to grow based on lower cost of deployment, user demand, and new mobile applications. The latest generation enterprise WiFi solutions offer the performance to address most users� network access needs, plus administration and management capabilities that significantly lower the total cost of ownership. Meanwhile the cost and complexity of installing home WiFi networks have also dropped, giving many the firsthand experience of wireless connectivity in their homes. WiFi-enabled devices, such as PDAs and dual mode handsets, will help drive enterprise demand for WiFi access in the workplace, and users will want to have access to the business telephone system with these devices.

It is also evident that enterprise IP telephony is here to stay, as deployments of IP desksets have now surpassed traditional TDM and analog sets. IP telephony enables unified communication capabilities with other IP-based communication applications, such as e-mail and instant messaging. Delivering these integrated applications to handheld devices will further increase the value of WiFi telephony by making employees even more accessible.

WiFi telephony has come a long way in a short time thanks to rapid innovations in wireless networking and VoIP and it�s making a positive business impact in many deployments today. As enterprises plan their IT strategies around IP networks, unified communications and wireless, it is critical they consider WiFi telephony to make employees more mobile, responsive and productive. IT

Ben Guderian is vice president of Market Strategy and Industry Relations at SpectraLink. For more information, please visit the company online at

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