Symptom

SM-X based L2 Ethernet switching module: Interface keep flapping when configure 100M Full with crossover cable to peer Catalyst 3750/3650 switch

Conditions

Modules affected: SM-X-16G4M2X, SM-X-40G8M2X C-SM-16P4M2X C-SM-40P8M2X Connect the GE ports on affected modules to a peer Catalyst 3560 or 3750 switch. configure speed 100 and duplex full on both sides, connect a crossover cable between them, the link will be flapping continuously. Connect a straightforward cable doesn't have this issue. *Mar 17 04:10:19.418: %LINK-3-UPDOWN: Interface GigabitEthernet3/0/2, changed state to down *Mar 17 04:10:20.419: %LINEPROTO-5-UPDOWN: Line protocol on Interface GigabitEthernet3/0/2, changed state to down *Mar 17 04:10:23.417: %LINK-3-UPDOWN: Interface GigabitEthernet3/0/2, changed state to up *Mar 17 04:10:25.420: %LINK-3-UPDOWN: Interface GigabitEthernet3/0/2, changed state to down *Mar 17 04:10:35.416: %LINK-3-UPDOWN: Interface GigabitEthernet3/0/2, changed state to up *Mar 17 04:10:37.420: %LINK-3-UPDOWN: Interface GigabitEthernet3/0/2, changed state to down *Mar 17 04:10:47.421: %LINK-3-UPDOWN: Interface GigabitEthernet3/0/2, changed state to up *Mar 17 04:10:49.423: %LINK-3-UPDOWN: Interface GigabitEthernet3/0/2, changed state to down *Mar 17 04:10:53.421: %LINK-3-UPDOWN: Interface GigabitEthernet3/0/2, changed state to up *Mar 17 04:10:55.424: %LINK-3-UPDOWN: Interface GigabitEthernet3/0/2, changed state to down *Mar 17 04:10:59.424: %LINK-3-UPDOWN: Interface GigabitEthernet3/0/2, changed state to up

Workaround

Replace with a straightforward cable.

Further Problem Description