How to configure a CVR-QSFP-SFP10G through I2C

grensink · ‎07-31-2018

Our company bought several 40G to 10G adapters (part no.CVR-QSFP-SFP10G). I have experience with this type of adapter so I expected this device to be a passive feedthru device that allows me to configure and status the SFP+ module that I plugged into this adapter. However, the I2C status that I am seeing is the adapter itself, not the plugged in SFP+ module.

Is there a datasheet that describes the mapping of the I2C addresses that will allow me to use this device as a passthru? I am able to read the 256 bytes at the 0xA0 offset of this device and I am able to write some of these addresses.

Marvin Rhoads · ‎07-31-2018

What platform are you using the modules in?

Generally speaking there is a command (varies by platform) to tell the switch to recognize the inserted adapter as having multiple interfaces. for instance, on a Nexus 3k, there is the following:

https://www.cisco.com/c/en/us/td/docs/switches/datacenter/nexus3000/sw/interfaces/6_x/b_Cisco_n3k_Interfaces_Configuration_Guide_602_U11/b_Cisco_n3k_Interfaces_Configuration_Guide_602_U11_chapter_010.html#task_4AF0989035354997AEDCBF4DC39E7E55

Nexus 5k and 6k have the following:

https://www.cisco.com/c/en/us/td/docs/switches/datacenter/nexus5000/sw/operations/interfaces/602_n1_1/N5K_Interfaces_Ops_Guide/n5k_qsfp-_portsoperations.html#wp998392

...etc.

grensink · ‎08-01-2018

I am not using a Cisco platform to host the adapter, so I can't use the normal Cisco platform commands to access it. It seems like there should be a Cisco datasheet on the adapter itself that describes the I2C address mapping. Isn't this supposed to be a general purpose device that can be used with any other vendor's boards?

Marvin Rhoads · ‎08-02-2018

@grensink wrote:

...Isn't this supposed to be a general purpose device that can be used with any other vendor's boards?

No, it's not.

grensink · ‎08-02-2018

Thank you for the timely response. I will recommend to my company management that they look into returning these parts. And that they reconsider the purchase of other Cisco products.