Nexus 5672UP 10GBASE-SR port won't link to a 1G SX peer and shows 'SFP checksum error'
4
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 Gbps transceiver produced the same 'SFP checksum error'. The poster asked how to get the link up and whether a 10 Gbps transceiver can talk to a 1 Gbps transceiver at the other end.
- Hardware: Cisco Nexus 5672UP, unspecified peer switch with 1G SX SFP
- Transceivers: 10GBASE-SR SFP+ (unspecified part), 1000BASE-SX SFP (unspecified part)
- Form factor: SFP+, SFP
Symptoms / messages:
SFP checksum error in show interface brief
10GBASE-SR port cannot link to 1000BASE-SX peer
link down after changing port speed
Comments 2
Accepted: SFP/SFP+ transceivers are single-speed, so a 10 Gbps optic on one end requires a 10 Gbps optic on the other; the speeds must match on both ends of the link.
A respondent said an SFP checksum error means the module is either faulty, not Cisco-branded, or counterfeit.