Cook said he looks forward to having SIP functionality throughout the network and down to each phone. Cisco is "moving in the direction we've asked for and want," he said.

Telesphere Ltd., a provider of IP telephony managed services in Scottsdale, Ariz., has been using Unified Communications internally for the past four months and began deploying the technology to its customers last month, said CEO Dave Thomas. The SIP-based presence capabilities can help users quickly locate co-workers in other offices worldwide, Thomas said.

Although Cisco and Avaya will make news at VoiceCon, which starts today in Orlando, analysts said that Siemens AG and Nortel Networks Ltd. have had unified communications strategies for a while, but with some capability gaps.

"The really unique thing Cisco has done is to create a unified communications platform that it can deliver on its own," said Brent Kelly, an analyst at Wainhouse Research LLC in Duxbury, Mass.