Nortel Networks, North America's biggest telephone equipment maker, has filed for bankruptcy, hoping to save a once-profitable business whose decade-long decline has accelerated with the global economic crisis. Nortel's clients in the country include RCOM, BSNL, Bharti Airtel and GAIL (India). Nortel Networks owes $9 million to Indian IT companies such as Wipro ($3.1 million), Infosys and Tata Consultancy Services ($2.9 million each) according to court filings. In addition, Nortel, which is amongst the top three clients for the tier II software services firm Sasken Communication, is reported to owe an undisclosed amount to Sasken.