[j-nsp] acceptable/good laser receive power in case of different interfaces

Keegan Holley keegan.holley at sungard.com
Tue Aug 2 20:51:41 EDT 2011


2011/8/2 Joel Jaeggli <joelja at bogus.com>

>
> if these are sr multimode optics, the -15 number is low the -7 number is
> marginal and everything else is decent.
>
> either the -15 one is quite long ( for sr) or needs to be
> replugged/cleaned/reterminated
>
>
Yea I agree.  The -15 is a bit low unless it's is at the end of a really
long, low-quality fiber run I'd clean it and or replace the XFP.  It's
blasting out at +1 and receiving much less, there could also be a mismatch
of some sort.  There are lots of ways to mismatch optics and cabling and
still get link.



> On Aug 2, 2011, at 2:53 PM, chip wrote:
>
> > Depending on whose optics you're using there should be a data sheet
> > that shows the acceptable Tx/Rx levels for each type available from
> > your vendor.  I can't seem to locate a document for Juniper at the
> > moment.  But I assume they shouldn't be that far off from Cisco stuff.
> > For example, here's a data sheet for the XENPAK module:
> >
> >
> http://www.cisco.com/en/US/prod/collateral/modules/ps2797/ps5138/product_data_sheet09186a008007cd00_ps5455_Products_Data_Sheet.html
> >
> > Check Table-2.
> >
> > As far as I know, an optic will output power within a specified range
> > as according to what type it is, SR, LR, ER, ZR, etc...
> >
> > Hope that helps a bit.
> >
> >
> > On Tue, Aug 2, 2011 at 5:26 PM, Martin T <m4rtntns at gmail.com> wrote:
> >> What is the acceptable Rx power in case of SFP/XFP? For example, here
> >> are XFP Tx and Rx signals from six FXP's:
> >>
> >> 1:
> >> Laser output power                        :  1.2920 mW / 1.11 dBm
> >> Laser rx power                            :  0.0285 mW / -15.45 dBm
> >>
> >> 2:
> >> Laser output power                        :  0.6420 mW / -1.92 dBm
> >> Laser rx power                            :  0.3054 mW / -5.15 dBm
> >>
> >> 3:
> >> Laser output power                        :  0.4230 mW / -3.74 dBm
> >> Laser rx power                            :  0.5092 mW / -2.93 dBm
> >>
> >> 4:
> >> Laser output power                        :  0.4180 mW / -3.79 dBm
> >> Laser rx power                            :  0.4208 mW / -3.76 dBm
> >>
> >> 5:
> >> Laser output power                        :  1.0920 mW / 0.38 dBm
> >> Laser rx power                            :  0.1801 mW / -7.44 dBm
> >>
> >> 6:
> >> Laser output power                        :  0.7680 mW / -1.15 dBm
> >> Laser rx power                            :  0.3337 mW / -4.77 dBm
> >>
> >>
> >> Is there some sort of pattern? It looks like if the Rx signal is
> >> lower, the Tx is higher? And what can one consider a decent Rx laser
> >> power level?
> >>
> >>
> >> regards,
> >> martin
> >> _______________________________________________
> >> juniper-nsp mailing list juniper-nsp at puck.nether.net
> >> https://puck.nether.net/mailman/listinfo/juniper-nsp
> >>
> >
> >
> >
> > --
> > Just my $.02, your mileage may vary,  batteries not included, etc....
> >
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> >
>
>
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