Accepted Solutions
The numbers you mention are off. I've pasted below a more typical signal strength range (for a 10Gbase-SR transceiver in this case, but others have similar values). Open in new tab to zoom.
Transmit power is typically good when it is in the 6 dB range between -1 and -7 dBm.
Receive power is normally expected between - 1 and -9.9 dBm.
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 the "noise floor" of the receiver stage. (https://en.wikipedia.org/wiki/Noise_floor)
When we see a Rx power around -14 dBm or lower there is typically some sort of fault in the cable plant (bad splice, dirty connector, poorly seated jumper etc.) that's causing excessive signal loss.
You might see it on a healthy link if it's know to be a long outside plant run (tens of km) with a measured signal loss (using OTDR fiber test kit) that would cause such loss. In those cases we would be using the more expensive long haul transceivers that are more capable of sending and receiving usable signal under those more extreme situations.
The numbers you mention are off. I've pasted below a more typical signal strength range (for a 10Gbase-SR transceiver in this case, but others have similar values). Open in new tab to zoom.
Transmit power is typically good when it is in the 6 dB range between -1 and -7 dBm.
Receive power is normally expected between - 1 and -9.9 dBm.
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 the "noise floor" of the receiver stage. (https://en.wikipedia.org/wiki/Noise_floor)
When we see a Rx power around -14 dBm or lower there is typically some sort of fault in the cable plant (bad splice, dirty connector, poorly seated jumper etc.) that's causing excessive signal loss.
You might see it on a healthy link if it's know to be a long outside plant run (tens of km) with a measured signal loss (using OTDR fiber test kit) that would cause such loss. In those cases we would be using the more expensive long haul transceivers that are more capable of sending and receiving usable signal under those more extreme situations.
