[j-nsp] Do the old M-series fixed optic SONET/SDH PICs wear out?

[Keegan Holley]

On Mar 14, 2014, at 5:06 PM, Will Orton <will at loopfree.net> wrote:

> I have a couple P(E)-4OC3-SON-SMIR that I purchased used and successfully ran in a 
> production network in the 2007-2009 timeframe. Then, about 5 years ago the OC3 
> links were taken out of service and the PICs sat in their routers (an M10 and an 
> M20) for 4-5 more years doing nothing.
> 
> The ports were set "disable" but the PIC was online, so I believe the optical 
> transmitters were still active.

Could just be dust/debris even if someone put the boots back on, which sometimes doesn’t happen.  SMIR is very sensitive dirt.
> 
> Now I'm trying to reussurect them for lab use and I cannot for the life of me get 
> them to link up back-to-back. Only one port out of eight will even go "green" when 
> looped to itself with a 1m patch cable. None will link port-to-port.
> 
> LOL clears and I get PLL lock, but then either LOS or LOF, AIS, BERR, etc on 
> both sides.
> 
> I've tried:
> -multiple patch cables (yes they're SMF)
> -cleaning the cables' SC connector with tissue/alcohol

This is a bad idea.  You could replace tiny dust particles with giant tissue fibers twice as big but still too small to see.  A proper fiber cleaner is about $100.  If you don’t have access to one you should just replace cables.

> -blowing canned air into the ports on the PIC

Bad idea as well. You’re actually more likely to blow things into the connectors than away from them.

> -5 & 10db optical attenuators in case it was rx overload even though that 
> shouldn't matter

I’ve never had to attenuate in a lab even with SMIR optics and 1-2m cables, but YMMV.  To quote my old SE, “Juniper likes it hot!”.

> -verifying tx/rx strands and swapping just in case
> -every combination of clocking,enable/disable scrambling, crc16/32, etc
> -JUNOS 10, 11, and 12 in both M10 and M20 with FPC-E
are you sure the new code is compatible with those cards?

Are the optics swappable? I can’t remember for that card.  I’d try new ones or at least try known good ones in all the non-working ports.

> 
> 
> Unfortunately I don't have a light meter. But I'm starting to think the 
> transmitters might just be toast and not pushing enough light to present a 
> usable signal to the other end even with only a 1m patch.

You do actually have a moderately accurate light meter.  There’s a command that will show you light levels from the perspective of the PIC IIRC.  I can’t guarantee that it is supported on hardware this old though so YMMV.  I believe it’s under the show interfaces physical hierarchy.  It should tell you what it’s transmitting, what it’s receiving and the minimum light level to establish a link.

Over the years, I’ve also taken to simply taking the known good port and cable and plugging it into all the stuff that didn’t work.  I would sometimes end up with cables pulled through racks and other dodgy places temporarily, but I always ended up invalidating some of my deductions.

> 
> http://www.juniper.net/techpubs/software/junos/junos85/swconfig85-network-interfaces/id-12763130.html
> 
> says:
> 
> "To extend the life of the laser, when a SONET/SDH PIC is not being actively used 
> with any valid links, take the PIC offline until you are ready to establish a link 
> to another device. To do this, issue the request chassis pic offline fpc-slot 
> slot-number pic-slot slot-number operational mode command"
> 
> Is this a real thing? Is 10-15 years in the expected usable lifetime of a 
> circa-2001 1310nm laser?

Yes. no. maybe. probably. definitely.  sometimes…   I’ve seen gear used well beyond it’s expected lifetime and I’ve seen things come out of the depot completely unusable.  Everything breaks.  Stuff is either broken or not broken yet.  That’s why hardware lifecycle’s were invented.  If there’s no current in the components they will last longer at least according to the laws of physics.  That doesn’t mean that leaving one on for 5 years will definitely fry it.

> 
> 
> -Will Orton
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