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Receiver-overload warnings on a 10G SFP link: optical power is not negotiated; newer MMA2P00-AS revisions run hotter

Asked Active Viewed 61 Original language: English
3

An embedded device with a 10GbE SFP transceiver kept logging power warnings above 800 mW and occasional errors when fed by an NVIDIA/Mellanox MMA2P00-AS 10/25G transceiver over a 2 m OM3 LC patch. The poster assumed transmit power is negotiated between the two ends and asked whether a failed negotiation could overdrive the receiver.

  • Hardware: embedded device with 10GbE SFP port
  • Transceivers: NVIDIA MMA2P00-AS SFP28 SR
  • Form factor: SFP+, SFP28

Symptoms / messages:

power warning > 800 mW
occasional link errors
receiver overload

Comments 2

Accepted answer

Optical power is not negotiated; on very short links an inline attenuator (cheap ones from FS.com) is the standard remedy, or choose a lower-launch-power short-reach transceiver.

3 South Koreawaverunner63KR Original (English)

The root cause was a transceiver revision change: newer Rev A3 MMA2P00-AS units transmit more power than the A7/A8 units used during development, and the embedded receiver has little tolerance.

2 GermanywavesmithDE Original (English)
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