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ACCOUNTS RECEIVABLE
 12 Months Ended
Oct. 30, 2021
Receivables [Abstract]  
ACCOUNTS RECEIVABLE ACCOUNTS RECEIVABLE
As of October 30, 2021, two customers accounted for 15.0% and 10.0% of net accounts receivable, respectively. As of October 31, 2020, no customer accounted for 10.0% of net accounts receivable. Ciena has not historically experienced a significant amount of bad debt expense. The following table summarizes the activity in Ciena’s allowance for credit losses for the fiscal years indicated (in thousands):
Year EndedBeginning BalanceEffect of adoption of new accounting standard (Note 1)ProvisionsNet DeductionsEnding Balance
November 2, 2019$17,378 $— $6,740 $4,017 $20,101 
October 31, 2020 (1)
$20,101 $— $8,855 $18,358 $10,598 
October 30, 2021$10,598 $2,206 $2,346 $4,238 $10,912 
(1)The reduction in Ciena’s allowance for credit losses as of October 31, 2020 compared to November 2, 2019 is primarily due to the final settlement from a significant asset impairment of $12.2 million for a trade receivable related to a single customer in the APAC region recorded in fiscal 2017.