Nortel is a company that dominates the internet/telephony backbone market, with a huge market share. While Cisco Systems, currently dominates the router/switch market on the enterprise side, Nortel dominates the systems that form the backbone of the internet.
Nortel's business stratgey has thus far been to develop a telecommunications technology up to the point at which it becomes an efficiency game, where companies compete to lower their cost of production/maintainence by a few dollars, at which point they usually sell of that division.
The new focus in the company is development in Optical Networking, and Wireless Networking, where it competes with companies like Lucent, and Alcatel. In the router market, Nortel dominates the market for large telecoms, whereas their main competitor dominates the market for enterprise switching and routing. Nortel is a technology company, and not a telecom.
Nortel is based in Ontario, Canada, though it has divisions throughout the world.