A customer saw errors on a fibre link and suspected a speed mismatch with a 1G far end. The poster asked whether 10G SFP+ transceivers are backward compatible with 1G, or whether the modules had to be swapped for 1G SFPs to talk to the gigabit device on the other side. Hardware involved: Aruba…
A Cisco Nexus 5672UP fitted with a 10GBASE-SR SFP+ could not connect to another switch that uses a 1000BASE-SX (1 Gbps) transceiver; both ends are multimode optics. When the poster changed the port speed, 'show interface brief' displayed an 'SFP checksum error', and swapping the Nexus optic for a 1…
The poster's newly acquired Cisco Catalyst 9300 (with an 8-port 10G SFP+ network module) would not link to a Cisco Catalyst 4503-E that only has 1G SFP ports. Suspecting a 10G-versus-1G speed mismatch, the poster tried to force the 9300's 10G SFP to operate at 1G with the 'speed' command, but the…
The poster asked whether a 10G SFP+ SR or LR optic in one switch can auto-negotiate down to 1G to link over fiber with a 1G SFP in another switch, and if not, how to attach a handful of 1G optical connections from a 1G switch to a 10G switch. They understood that Cisco SFP+ optics run only at 10G…