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Dear colleagues, In the last BWA conference call, if I recall correctly, someone stated that for applications like financial transactions, FEC is often turned off to reduce latency -- even for traffic between New York and Chicago. Please help me understand that. Light propagation delay in fiber is ~5 microseconds per kilometer. In contrast, FEC latency would be sub-microsecond. Even within a data center of 300 meter span, a round-trip through just one switch can add up to several microseconds. On the other hand, turning off FEC may increase BER and make TCP retransmissions more likely, thus adding to latency. Or is it that in such links, the BER is so low that FEC ends up being all latency and no benefit? Thank you. Regards, Vipul Vipul Bhatt Vipul_Bhatt@xxxxxxxx (408) 461-8521 NOTICE: The information contained in this e-mail message is intended for the exclusive use of the addressee(s) and may contain proprietary information. Any proprietary information contained herein should be handled per executed NDAs. If you are not the intended recipient of this message, you are hereby notified that any form of dissemination of this communication is strictly prohibited . Please note that any views or opinions presented in this email are solely those of the author and do not necessarily represent those of the company. Finally, the recipient should check this email and any attachments for the presence of viruses. The company accepts no liability for any damage caused by any virus transmitted by this email. Lightwire Inc, Suite# 412, 7540 Windsor Drive, Allentown, PA, USA, www.lightwire.com |