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Re: 100G QSFP28 DAC cables - experience


From: joel jaeggli <joelja () bogus com>
Date: Mon, 18 Sep 2017 14:03:43 -0700

On 9/6/17 00:17, Jiri Prochazka wrote:
Hi folks,

I'm wondering if anyone have (either positive or negative) experience
with 100G QSFP28 DAC cables?
I found the ones we tested to be substantially more finicky particularly
at 5 meter then 10gig dacs, adding 4 x 25 sfp28 breakout on the other
end probably isn't a help. We went with AOCs for the equivalent (3, 5
meter) lengths.
Is there anyone who is using 100G DAC in large scale and would
recommend it (which means there are no issues compared to SR4 links)?

I'm thinking about cables with lenght up to 1m, not more.

We have had quite bad experience with 10G DAC in the past - but I do
not want to be slave of the past.


10g dacs were less reliable then I would have preferred for  3 5 7 meter
distances but they were tolerable especially if you leave the bundles
alone, 25g was sufficiently less so at least in testing that we didn't
try it in the field, being at the limits at 5m was a sufficient
problemthat it ruled out some adjacent rack arrangements. so we're all
optical for 25/100

Thank you for your thoughts!



Jiri
    



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