Symptom
As per CPAK-10X10G-LR specification there is 1 laser for every 2 TX Channels. When a channel TX disable is asserted, we cannot turn the laser off, since the other channel (that the laser is connected to) needs to operate properly. We do put the modulator of the disabled channel into the high loss / attenuated state. However, it does not turn the channel off completely. That the power will be < -10 dBm.
However for some of the lanes we may see random power level (like -7, -6, -5 etc.) which doesn't meet the specification.
RP/0/RP0/CPU0:ASR9912-A#sh controllers Hu0/0/0/1 phy | inc mAmps
Fri May 20 06:18:13.564 UTC
Bias: 125.000 mAmps 110.000 mAmps 30.000 mAmps 25.000 mAmps
0 N/A 53.146 mAmps 0.03930 mW (-14.05607 dBm) 0.49900 mW (-3.01899 dBm)
1 N/A 52.968 mAmps 0.02910 mW (-15.36107 dBm) 0.000 mW (<-40.00 dBm)
2 N/A 50.966 mAmps 0.17290 mW (-7.62205 dBm) 0.000 mW (<-40.00 dBm) <---
3 N/A 51.144 mAmps 0.22700 mW (-6.43974 dBm) 0.000 mW (<-40.00 dBm) <---
4 N/A 50.860 mAmps 0.02090 mW (-16.79854 dBm) 0.000 mW (<-40.00 dBm)
5 N/A 51.048 mAmps 0.03230 mW (-14.90797 dBm) 0.00490 mW (-23.09804 dBm)
6 N/A 49.900 mAmps 0.01880 mW (-17.25842 dBm) 0.000 mW (<-40.00 dBm)
7 N/A 49.722 mAmps 0.04310 mW (-13.65523 dBm) 0.000 mW (<-40.00 dBm)
8 N/A 53.282 mAmps 0.02740 mW (-15.62249 dBm) 0.000 mW (<-40.00 dBm)
9 N/A 53.096 mAmps 0.02700 mW (-15.68636 dBm) 0.64080 mW (-1.93277 dBm)
Conditions
CPAK-10X10G-LR + interface in the shutdown state.
This problem is seen only in Tengig interface 0 to 3.
Affected PIDs are:
A9K-8X100GE-SE
A9K-8X100GE-TR
A9K-4X100GE-SE
A9K-4X100GE-TR
Workaround
Do 'no shut' & 'shut' on the affected interface. But it is not reliable workaround.
