In fact, analysts said Cisco's announcement late last month that it plans to offer at least some pieces of its IP voice technology as a hosted service could be viewed as a direct response to Google's recent move to start limited release of its Web-based Google Voice and communications tools.

During a press briefing at the Cisco Live user conference in San Francisco late last month, Doug Dennerline, Cisco's senior vice president of collaboration software, acknowledged the challenge from Google and said his company is set to "invent and reinvent" its .

Analysts said that the Google Voice Internet telephony service, now available to early users by invitation, and Google Wave, a hosted collaboration and communications service released to developers early this month, may pose long-term problems for companies like Cisco and Microsoft Corp.

The Google products could provide users with a less expensive common platform for delivering messaging, voice and video services to consumers and office workers, they said.

The was launched in March for a limited customer base: users of its predecessor, Grand Central, a service the search vendor had acquired almost two years earlier. Late last month, Google began inviting selected new users to the service, which has attracted widespread attention for its call-screening capabilities and its ability to provide a single phone number for multiple devices.