Jono, The secret is that none of this autonegotiates. You have to set the link speed and the link width explicitly on the switch. The switch you own, a N8550-32C, with 100 gig ports, was able to talk to a Google Transfer Device with a 40 gig port, after explicitly setting the speed down on the switch. I used a cable with QSFP28 ends.
I think FEC is the same way, it'll be on by default in 100gig and 25 gig settings, but you can disable it on the switch if you like. And Mellanox cards, for example, do have a setting that turns off FEC. Why does none of this autonegotiate? I don't understand why, it's quite similar to Infiniband and PCI Express, both of which autonegotiate. -- greg -- You received this message because you are subscribed to the Google Groups "[email protected]" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To view this discussion on the web visit https://groups.google.com/a/lists.berkeley.edu/d/msgid/casper/20221201001617.GA14629%40rd.bx9.net.
