Usually on Multi-mode and Low-power single-mode optics the MaxOutputOpticalPower is less than or equal to the MaxInputOpticalPower, so it's not necessary to attenuate. The trade-off is optimized optics versus having an attenuator sticking out the front of the electronics. Something along the lines of -9.5 to -4 transmit power and -18 to 0 on the Receive power. Multi-Mode optics tend to be more application specific than single-mode A good rule of thumb is keep a minimum of 4dB off the bottom plus 20% of the optical budget, discounting any specific application the above optic would be optimal around -10dB. Daniel Jameson Manager - IP Network Engineering TDS Telecom -----Original Message----- From: NANOG [mailto:nanog-bounces@nanog.org] On Behalf Of Faisal Imtiaz Sent: Wednesday, February 11, 2015 2:48 PM To: NANOG Subject: MultiMode Fiber Connectivity... (850nm) Power Question Hello, I was looking for feedback on the following question:- When connecting two MM SFP/SFP+/XFP 's together...(short range). What should be the best practice receive power range ? Is it true that if the rx power is higher than (x?) then it shortens the life of the optics ? (assumption being made here is that MAX Rx Power is not being exceed as per the spec sheets of the optics) Regards Faisal Imtiaz Snappy Internet & Telecom 7266 SW 48 Street Miami, FL 33155 Tel: 305 663 5518 x 232 Help-desk: (305)663-5518 Option 2 or Email: Support@Snappytelecom.net