[c-nsp] forced up/up on a fiber link

[Damian Holdcroft]

I remember reading something, somewhere, about the lasers sending pulses
for link detection. I don't seem to be able to find anything on fibre link
detection at the moment though. Does anybody know anything about it?

It would be interesting to see if the hw-module command actually engaged
the optics. I wouldn't have thought so. Bit of a bugger you can only
simulate entire linecards!

I'll be trying the mobile phone camera next opportunity. Thanks!


On Mon, Oct 22, 2012 at 10:51 PM, Saku Ytti <saku at ytti.fi> wrote:

> On (2012-10-22 22:29 +1100), Damian Holdcroft wrote:
>
> > Either way, I would imagine a fibre port would not play ball. It would
> be a
> > potential hazard - a laser firing into air could damage some eyes. I
> > haven't seen a fibre port report link-up without something to
> participate.
>
> All SFP/XFP/XENPAK/SFP+ I've seen happily 'fire into air'. I've not seen in
> SFP specification any way to event detect if cable is plugged or not.
>
> As homework, go to your lab and point your mobile phone camera to laser TX,
> preferably SR or something, as your IR filer may cut out 15xxnm.
>
> set gigaether-options loopback. Is enough to bring fibre interface 'up'
> from RPD point of view in JunOS.
> But even without that, the laser is firing until 'set disable' (and this
> works in MX, but not in all JNPR, in many JNPR here is no way to turn laser
> off)
>
> --
>   ++ytti
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