nanog mailing list archives

Re: 60 ms cross-continent


From: Saku Ytti <saku () ytti fi>
Date: Sun, 21 Jun 2020 09:08:06 +0300

On Sat, 20 Jun 2020 at 23:14, Bryan Fields <Bryan () bryanfields net> wrote:

I think he might be referring to the newer modulation types (QAM) on long haul
transport.  There's quite a bit of time in uS that the encoding takes into QAM
and adding FEC.  You typically won't see this at the plug-able level between
switches and stuff.

FEC is low tens of meters (i.e. low tens of nanoseconds), QAM is less.
Won't impact the pipeline or NPU scenarios meaningfully, will impact
the low latency scenario.

-- 
  ++ytti


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