Thanks also for this information, Greg, also helps and I very much appreciate it.
Best wishes, Jonathan > On Nov 30, 2022, at 7:16 PM, Greg Lindahl <[email protected]> wrote: > > 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://www.google.com/url?q=https://groups.google.com/a/lists.berkeley.edu/d/msgid/casper/20221201001617.GA14629%2540rd.bx9.net&source=gmail-imap&ust=1670458582000000&usg=AOvVaw3CZhskrFQaB_1SwVN-YSID. -- 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/1BE767DA-672C-48AB-8E90-870380DDC17A%40cfa.harvard.edu.
