Cisco Systems said Friday it plans to buy instant messaging platform vendor Jabber, a move that could heighten its battle with Microsoft over the collaboration and office communications market.

Terms of the deal, which is expected to be completed in the first half of Cisco's fiscal 2009, were not disclosed.

Jabber, based in Denver, has developed a "carrier-class" platform based on open standards that can work across multiple messaging systems, such as AOL Instant Messenger, Google Talk, Yahoo Messenger and Office Communications Server.

"Enterprise organizations want an extensible presence and messaging platform that can integrate with business process applications," said Doug Dennerline, Cisco senior vice president, Collaboration Software Group, in a statement. "With the acquisition of Jabber . . . our intention is to be the interoperability benchmark in the collaboration space."

The pending Jabber deal comes just a few weeks after Cisco took another shot across Microsoft's bow by announcing plans to buy PostPath, maker of e-mail and calendaring software.