TORONTO, Sept 18 -- Nortel Networks Corp. will supply fiber optic products to Savvis Communications Corp., an IP network service provider based in Herndon, Va., in a deal worth an estimated $155 million. Nortel will supply its long-haul network equipment to Savvis, which is building an optical network to connect 50 Canadian and US markets over a 42-month period. Nortel will also supply professional services such as program management, engineering and equipment installation, and assistance in building a network operations center. Savvis will build its own fiber optic network, to be in place by the fourth quarter of 2001, to replace the lines it leases from other services providers.