COLORADO SPRINGS, Colo. — IBM Corp. and Nortel Networks Inc. are expanding an existing joint development pact on IP Multimedia Subsystems to cover new software integration and new facilities to carry out joint interoperability testing.

The IMS collaboration is centered on IBM's BladeCenter hardware architecture.

IBM has agreed to integrate Nortel VoIP and Fixed Mobile Convergence software into its IMS suite, while Nortel will be using IBM's WebSphere Presence and Group List Enabler in its IMS portfolio. Both companies will offer pre-integrated product suites to carriers.

In order to speed interoperability testing and joint development projects, the partners will open a new IMS center at Nortel's campus in Richardson, Texas. They also will expand collaboration at IBM's Telecom Solutions Innovation Center in Montpelier, France.