Wi-Fi Telephony Answers the Call for WLAN-Enabled Applications

Significant technological progress toward providing enterprise-grade security and management is offset by lack of compelling strategic value.

For IT departments of highly mobile organizations (such as retail, warehousing, and healthcare), Wi-Fi telephony offers a way to justify the costs associated with WLAN. This quest for ROI has pushed Wi-Fi telephony to the top of the WLAN industry priority list. WLAN products that support VoIP technology are now available from enterprise voice equipment providers such as Cisco and Nortel, from startups such as Telesym and Vocera, as well as from early wireless telephony specialists such as Spectralink and Symbol.

Trend Impact
Delivering enterprise data services over WLAN is a sizeable task that requires advanced features such as authentication and encryption, roaming, and load balancing. Wi-Fi telephony adds an additional layer of complexity that many existing products are unable to handle.

Major challenges associated with Wi-Fi telephony include:

• Voice prioritization: Wi-Fi systems do not currently support QoS. Although the 802.11e standard for QoS will likely be finalized by next year, vendors will continue to offer proprietary protocols in highly congested area.
• Security: As with data over WLAN, Wi-Fi telephony can leverage existing security protocols such as WEP, WPA, and VPNs. However, the demands of strong security on the network (which introduces latency) can have a direct impact on voice quality.
• Handoff: WLAN access points must be able to support faster handoffs to enable Wi-Fi telephony. Most general-purpose access points are not equipped to support fast switching for efficient handoffs.
• Capacity: Maximizing bandwidth for voice applications requires aggressive compression algorithms and frequency planning capabilities. This is particularly sensitive in environments where voice and data are in simultaneous use.

Despite these challenges, our WLAN survey indicates strong interest for Wi-Fi telephony among organizations that plan to deploy WLAN within 12 months. This is good news for WLAN voice pure-plays such as Spectralink, whose proprietary systems were formerly limited to serving niche markets. The survey also bodes well for the emerging class of enterprise-grade WLAN solutions—both startups and incumbents that address the issues discussed above. Moreover, the technical and strategic requirements of Wi-Fi telephony will help sort out the crowded enterprise WLAN market.

Increasing use among vertical markets and specific departments within organizations (e.g., IT and facility managers) that have high mobility requirements will continue to expose the strengths and weaknesses of existing Wi-Fi telephony solutions. Over the next 6 to 12 months, we anticipate growing availability of lower-priced Wi-Fi telephony handsets from Taiwanese ODMs as well as dual-mode Wi-Fi/WAN handsets from traditional handset vendors like Motorola. Service providers will also begin to enter the market to deliver WLAN voice integration and services to enterprises and SMBs.

Vendor and Carrier Recommendations

• Voice gateways must be able to support multiple Wi-Fi telephony clients. Each user segment has different requirements uses different devices. Customers are accustomed to the interoperability of Wi-Fi data devices and will demand the same from voice clients.
• Carriers should leverage their expertise in voice to gain access to enterprise WLAN networking opportunities. VoIP gateway and PBX integration requires complex services that carriers are well suited to provide. Carriers should place position themselves to be the provider of choice for voice on and off enterprise premises.
• Vendors should partner across the Wi-Fi telephony value chain — including mobile device manufacturers, service providers, wireless networking equipment providers, and application developers—to deliver solutions that maximize the value of the customer’s WLAN network.

Enterprise Recommendations

• Understand the tradeoffs. This is the key to a successful Wi-Fi telephony deployment. If mobile data is the most critical application to your organization, consider a separate network for voice only.
• IT and telecom managers should fully understand usage requirement of the organization before moving to Wi-Fi telephony. Wi-Fi telephony can compromise data performance. In certain cases, proprietary solutions will better serve the telephony needs of the company.
• Look for WLAN management solutions that support centralized management of remote Wi-Fi telephony as well as data devices. Reducing the cost of intra-office calling is a compelling reason for deploying Wi-Fi telephony. However, supporting Wi-Fi telephony across multiple offices carries costs associated with the management with of remote offices.

The Yankee Group originally published this article on 2 October 2003.