[c-nsp] Possible causes for fiber link flap?

Peter Rathlev peter at rathlev.dk
Thu Oct 10 12:17:17 EDT 2013

On Thu, 2013-10-10 at 16:57 +0200, Erik Klaassen wrote:
> 2.4dB loss over 3km is not in g652 spec.
> max dampening @1550 should be something like: (Length in Km *
> 0.25)+(Number of connectors * 0.5)+(number of splices * 0.1)

If the SFP+ to fiber interface counts as a connector we have six of
those. Using Cisco's numbers[0] we should see around 2.8dB loss end to
end, and their numbers are lower than yours.

I thus don't think 2.4dB loss in unreasonable; the DOM measured 0.6dB in
the other direction was suspicious because of the asymmetry. After
having moved things around some more we don't see that number anymore.
It was probably an artifact of some kind.

[0]: http://www.cisco.com/en/US/products/hw/optical/ps2006/products_tech_note09186a00800e6eeb.shtml#topic1


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