[c-nsp] SFP high power alarm

[Andrew Koch]

On Tue, Aug 21, 2012 at 5:13 AM, marc williams <marcuk at me.com> wrote:
> 10 GIG cisco compatible SFP in a 3750-X switch.
> we started to see this error message after a fibre break and repair:
>
> %SFF8472-5-THRESHOLD_VIOLATION: Te4/1/2: Tx power high alarm; Operating
> value:   0.6 dBm, Threshold value:   0.0 dBm
>
> Cant see how the TX power can go high? any ideas? Interface is up and
> working ok.

The transceiver may be reporting reflected signal.  Any splice will
have some reflection, a poor splice may cause high reflected power
back into the transmitter and potentially cause damage.

This is also true for connectors - they will cause reflection of the
signal.  This is why APC (angle polished connectors) are used in
high-power environments.

You will want to check your fibers for reflection.  An OTDR read-out
from before and after the splice event would be optimal.

HTH,
Andy