As enterprises increase Wi-Fi adoption, interest in wireless voice over IP (or voice over Wi-Fi) has grown. The in-building wireless voice industry has stagnated, with carrier cellular solutions proving cost-prohibitive and incumbent wireless private branch exchange (PBX) extension solutions being phased out (e.g., Nortel Companion). By 2H04, all major IP telephony vendors will offer voice over Wi-Fi integrated into their existing IP telephony solutions (many through partnerships with SpectraLink). Despite the relative immaturity of Wi-Fi and IP telephony, we anticipate a significant rise in the number of mobile devices capable of supporting voice over Wi-Fi, with the adoption of SIP delivering basic interoperability between mixed vendor devices and IP PBXs. Voice over Wi-Fi provides new flexibility, but users with high expectations for voice quality should proceed cautiously due to significant scalability, performance, and security issues. Integration of cellular and Wi-Fi for telephony will not achieve significant adoption through 2008.
Bottom Line: Voice over Wi-Fi is in its infancy. Deployments should not be targeted at desk phone displacement, but rather at small-scale applications in which true user mobility is a requirement.
META Group originally published this article on 25 November 2003.