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Fibre Channel (SAN)

New Member
Posts: 1
Registered: ‎06-19-2018

what does means 16 dBm in the description of SFP?

Hi, the description of SFP 8G-ER-Dxxx-BR1 appears


                 SFP+, 8/4/2/1 Gbps FC/FICON, DWDM, SM, DDM, 14dB, 40km


What is the interpretation of value 14dB?


for other hand in the specifications of the SFP in Receiver characteristics there are three parameters



Receiver Sensitivity @ 10.3GBps (RX_SENS)     -16  dBm

Loss of Signal-Asserted (PLOS_A)                       -28 dBm (min)

Loss of Signal-Deasserted  (PLOS_D)                  -16 dBm (max)


the same question, What's the interpretation of these values?

thanks in advanced


Broadcom Moderator
Posts: 108
Registered: ‎03-29-2010

Re: what does means 16 dBm in the description of SFP?

dBm is a reference of the ratio of power to a standard mW. The 14dB is what power the SFP will deliver at the output port, in reference to 1 mW. The recieve side will be working with a power level of -16dB or higher. 


Loss of Signal asserted means that when the recieve level falls below that value, the SFP will report to the FOS that a "loss of signal" has been reached. When the signal rises above -16dB, the SFP will not report to the FOS that a loss of signal has occured.


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