nanog mailing list archives

Re: 60 ms cross-continent


From: Bryan Fields <Bryan () bryanfields net>
Date: Sat, 20 Jun 2020 16:11:33 -0400

On 6/20/20 1:56 PM, Saku Ytti wrote:
On Sat, 20 Jun 2020 at 20:52, Wayne Bouchard <web () typo org> wrote:

And thus far, no one has mentioned switching speed and other
electronic overhead such as the transceivers (that's the big one,
IIRC.)
This will be something from tens of meters (low lat swich), to few
hundred meters (typical pipeline),  to 2km delay (NPU+FAB+NPU) per
active IP device. If that is a big one, I guess it depends, cross
atlantic, no, inside rack, maybe.

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.

60ms is nothing really, and I'm happy I don't need to play in the HFT space
anymore.  I do wish my home connection wasn't 60 ms across town as spectrum
wants takes TPA-ATL-DCA-DEN-NY to get to my rack. :-)
-- 
Bryan Fields

727-409-1194 - Voice
http://bryanfields.net


Current thread: