[c-nsp] c6500 Low alarms on optics

[Saku Ytti]

On (2014-01-07 14:02 +0100), "Rolf Hanßen" wrote:
> Hi,
> 
> what kind of optics is that ?
> 
> The readings rely on the optics used.
> Here an output of a system with some OEM LR optics and China DWDM:
> 
> I am quite sure the Xenpaks neither have -63 nor 104 degree Celsius. ;)

Are those statics? Do you graph them?

There is known ucode bug in microcontroller from one vendor. Optics need to
have some idea of time, so that they can avoid changing transmit levels
constantly etc.
In this ucode bug, timer is implemented as hundreds of a second in 31b, once
this is full, 248days, time leaks at memory where temperature is stored,
causing temperature to travel between -128 ... 128.

It may also cause link to start flapping (maybe due to I2C chatter, dunno),
which on Juniper platforms can even propagate to neighbours (so a-b-c, a has
broken optic facing b, and b-c can start flapping, because b is observing the
flaps and i2c handling or something cannot cope with this, causing problems
keeping b-c up)

'Solution' is to power cycle the optic before 248d comes up or replace optic.

-- 
  ++ytti