Understanding the Monitoring Thresholds or Reference Values for SFPs in the 32G/64G Used in the MDS 9000 series

[Translator]

Is there a monitoring threshold or reference value for the 32G/64G SFP used in the MDS 9000 series?

[marce1000]

  - Ref : https://www.cisco.com/c/en/us/td/docs/switches/datacenter/mds9000/sw/8_x/config/interfaces/cisco_mds9000_interfaces_config_guide_8x/configuring_interfaces.html
    Start reading from  SFP Counters

  M.

[Translator]

  - Ref : https://www.cisco.com/c/en/us/td/docs/switches/datacenter/mds9000/sw/8_x/config/interfaces/cisco_mds9000_interfaces_config_guide_8x/configuring_interfaces.html
    Start reading from  SFP Counters

  M.

[Translator]

The SFP data sheet is available here. Can you refer to it?
You can see the Max/Min value of Tx/Rx Power, which is also the threshold of the MDS Warning message.

Cisco MDS 9000 Series Pluggable Transceivers Data Sheet
https://www.cisco.com/c/en/us/products/collateral/storage-networking/mds-9000-series-multilayer-switches/product_data_sheet09186a00801bc698.html

[Translator]

Thank you for your teaching.
Certainly, the Average Tx/Rx parameter is listed in the Optical parameter item, but the light intensity is too wide, and the value is quite different from other companies' products.

As an experience, I was concerned that there was no more threshold information to be monitored because I would be offline much faster than the Average value here, or because I would receive an error count from Bad_Words and be errdisable by portguard.

In addition, when we examined information about SFPs from other companies' products, we determined the threshold value by referring to this value as the value of whether the OMA value meets the standard, but we did not have that information for Cisco, so I was asked.

Compliance with Industry Standards

OMA is an essential parameter for verifying whether an optical module meets industry standards, such as those defined by IEEE, ITU, and other regulatory bodies. During production and testing, OMA measurements are used to ensure the optical module meets the required performance thresholds and is suitable for deployment.
https://community.fs.com/encyclopedia/optical-modulation-amplitude-.html 


Transmit (Tx):
・ Wavelength: 840 nm to 860 nm
・ Spectral width: 0.6 nm
・ Average power: -7.5 dBm to 4 dBm
・ RIN: -128 dB/Hz max
· OMA: -4.5 dBm min (355 µW)
Receive (Rx):
・ Wavelength: 840 nm to 860 nm
・ Average power: 4 dBm max
・ Optical return loss: 12 dB min
· Unstressed sensitivity: -7 dBm (200 µW)
· SRS OMA: -2.4 dBm (575 µW)
・ 3-dB cutoff maximum: 18 GHz
https://docs.broadcom.com/doc/Brocade-64G-SWL-SFP+-Transceiver-Product-Brief 

[emazurek]

Hello M,

Each specific type of SFP has its own thresholds burned into the SFP. That's what you see when you do a 'show interface transceiver details'.  But we have found that FC links start to encounter errors as the Rx Power/Tx Power drop prior to hitting the low warning thresholds. Because of this we added the new counters into port monitor sfp-tx-power-low-warn and sfp-rx-power-low-warn. These new counters work on a percentage value since there are lots of different types of SFPs with different actual values.

So in general you want a percentage value less than 100% so that an alert is generated before the power levels get to the low warning threshold. 80% or maybe even 70%  could be a good starting value.

For example, a DS-SFP-FC32G LW SFP in my lab has a value of -14.00 dBm for the Rx Power Low Warning threshold. If a 'percentage 80' is configured for counter sfp-rx-power-low-warn it will alert at -11.2 dBm.  If 'percentage 70' then the value then it would be -9.8 dBm.

For more info and configuration samples you can reference this document on cisco.com:

https://www.cisco.com/c/en/us/support/docs/storage-networking/mds-9000-nx-os-software-release-62/200102-Sample-MDS-port-monitor-policy-for-alert.html

If there are further questions please let me know.

Thanks, Ed Mazurek

[Translator]

Hello M,

Each specific type of SFP has its own thresholds burned into the SFP. That's what you see when you do a 'show interface transceiver details'.  But we have found that FC links start to encounter errors as the Rx Power/Tx Power drop prior to hitting the low warning thresholds. Because of this we added the new counters into port monitor sfp-tx-power-low-warn and sfp-rx-power-low-warn. These new counters work on a percentage value since there are lots of different types of SFPs with different actual values.

So in general you want a percentage value less than 100% so that an alert is generated before the power levels get to the low warning threshold. 80% or maybe even 70%  could be a good starting value.

For example, a DS-SFP-FC32G LW SFP in my lab has a value of -14.00 dBm for the Rx Power Low Warning threshold. If a 'percentage 80' is configured for counter sfp-rx-power-low-warn it will alert at -11.2 dBm.  If 'percentage 70' then the value then it would be -9.8 dBm.

For more info and configuration samples you can reference this document on cisco.com:

https://www.cisco.com/c/en/us/support/docs/storage-networking/mds-9000-nx-os-software-release-62/200102-Sample-MDS-port-monitor-policy-for-alert.html

If there are further questions please let me know.

Thanks, Ed Mazurek