The success of the Internet has emboldened the networking technology industry, and European telecommunications companies are turning to the U.S. to acquire the technology needed to join in -- and, not so incidentally, to compete with American operators on their own turf. Britain's General Electric Co. PLC is spending $2.1 billion to acquire Reltec Corp., a network equipment supplier. The Reltec acquisition is expected to provide the British group with access to a new customer business with such U.S. telecommunications firms as AT&T Corp., Bell Atlantic Corp., and BellSouth. Meanwhile, in the wake of its agreement this week to buy Xylan Corp. for $2 billion, France's Alcatel SA, is acquiring Assured Access Technology Inc., Milpitas, Calif., for $358 million. The deals appear aimed at strengthening Alcatel's position in the fast-growing data networking market.