Technical Tip: FortiGate SFP+ER (Extrem Range) power sensitivity (dBm)

[serge_FTNT]

Description	This article discusses FortiGate SFP+ER (Extrem Range) power sensitivity (dBm).
Scope	FortiGate, planning cabling and attenuation (when the distance is less than 40km).
Solution	SFP+ER (Extrem Range) power sensitivity is not (yet) documented in below URL link below: https://www.fortinet.com/content/dam/fortinet/assets/data-sheets/Fortinet_Transceivers.pdf FN-TRAN-SFP+ER transceiver Part Number (P/N) are the following: FINISAR FTLX1672y3BXL. Finisar FTLX1672D3BCLFTN. Fortinet SFP documentation is planned to be updated with the below information: max tx power: 2dBm rx overload: -1dBm rx sensitivity (average): -16dBm General information for SFP+ER values: 'Receiver average optical input power' should be between -20dBm and +1dBm (±2dBm). Thus Rx Power shouldn't be higher than -3dBm to be safe. When the transceiver is in place, attenuators should be put to limit the received power on both Rx sides accordingly. Once plugged in and cabled, performing the below FortiGate CLI command will display SFP information (example for port5): get sys interface transceiver port5 Interface port5 - SFP/SFP+ (10.3G) Diagnostics : Unspecified Vendor Name : FORTINET Part No. : FTLXxxxxxxxxxxxx Serial No. : xxxxxxxxx Measurement Unit         Value  High Alarm  High Warning      Low Warning      Low Alarm ------------ ------------ ------------ ------------ ------------ ------------ ------------ Temperature (Celsius)       23.8             78.0           73.0 -              8.0              -13.0 Voltage (Volts)                    3.43           3.70              3.60              3.00              2.90 Tx Bias (mA)                       8.46          13.00          12.50               5.00            4.00 Tx Power (dBm)                  -2.7             0.0              -1.0               -5.0             -6.0 Rx Power   (dBm)               -1.9           0.0                -1.0               -18.0            -20.0