Transmit power is typically good when it is in the 6 dB range between -1 and -7 dBm. Have you ever encountered a Cisco switch interface that constantly flaps (goes up and down) or suddenly enters an err-disabled state? Before you blame the switch or replace the cable, you need to look at the invisible data: the light levels. If either Tx or Rx is in the -30 dBm or lower range that's usually indicative of there being no actual signal received and the transceiver is reporting. When designing optical networks, understanding the TX/RX power range is vital for ensuring optimal performance and long-term reliability. All ports below are 10gbps 850nm sm. See the one for port 2:59 has a * (star) next to RxPower. The reliability of this transmission depends entirely on the strength of that light signal as it reaches its destination.
