Nortel Networks Corp. said late Wednesday it won court approval in the U.S. and Canada to sell two of its business units.

The larger unit, Nortel's global optical networking and carrier ethernet businesses, is going to Ciena Corp. The business is one of the most sought-after assets of Nortel, a once-dominant network gear maker that is selling itself off in pieces after filing for Chapter 11 protection in January.

The deal gives Ciena all products, contracts, and intellectual property, including technology that improves the speed and capacity of fiber optic networks.

Bankruptcy courts in Delaware and Ontario approved the deal over objections by Finnish rival Nokia Siemens Networks, which said that it would be willing to pay $810 million in cash for the business with its partner, One Equity Partners.