03-11-2025 08:29 AM
Client is testing 100Gb throughputs on a pair of PA-5450s. We added the PA supplied QSFP28-CWDM4 (Finisar) transceiver into the Cisco switch and the Cisco logs revealed the transceiver is incompatible. But, in order to do 100Gb on the PA it is required that the transceiver be QSFP28 - so the PA side doesn't have the option of using anything but QSFP28.
We got the same QSFP28s working between a PA and Spirent for load testing, but now we need to lab out a real world environment and are stuck because we don't know which SFP would be required for the Cisco side.
Thoughts, pointers, directions?
Thank you.
03-11-2025 09:17 AM
As you need QSFP28 transceiver to Cisco side you should check with Cisco reseller.
03-11-2025 09:27 AM - edited 03-11-2025 09:30 AM
By default, Cisco blocks any SFPs that are not marked as manufactured by Cisco (or one of their sub vendors)... You can use a genuine Cisco SFP (something like a QSFP-100G-CWDM4-S or whatever depending on your port type and distance demands). Or you can override the Cisco block and use the Finisar SFP with the following command:
service unsupported-transceiver
Depending on the Cisco system you may also need to disable port shutdown on unsupported transceiver:
no errdisable detect cause gbic-invalid
Edit: The list of official Cisco QSFPs by distance and wavelength:
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