Does anyone have any advice for this weird issue?   I've got a MS420-24 connected to a few MS320-48LP in my network rack; one of the MS320's keeps dropping out when connected via SFP+ DAC, but is happy when connected via ethernet.   I've tried switching ports at each end, and have tried replacing the cable multiple times.   Here is my port config on the MS420   Jun 27 12:42:00   Port STP change Port 17 designated→disabled Jun 27 12:42:00   Port status change port: 17, old: 10Gfdx, new: down Jun 27 12:41:59   Port STP change Port 17 disabled→designated Jun 27 12:41:59   Port status change port: 17, old: down, new: 10Gfdx Jun 27 12:40:52   UDLD alert port: 17, state: unknown, port_blocked: false Jun 27 12:40:11   Port STP change Port 17 designated→disabled Jun 27 12:40:11   Port status change port: 17, old: 10Gfdx, new: down Jun 27 12:40:11   UDLD alert port: 17, state: unidirectional (outbound fault), port_blocked: true Jun 27 12:40:05   Port STP change Port 17 disabled→designated Jun 27 12:40:05   Port status change port: 17, old: down, new: 10Gfdx Jun 27 12:39:56   Port STP change Port 17 designated→disabled Jun 27 12:39:56   Port status change port: 17, old: 10Gfdx, new: down Jun 27 12:39:54   Port STP change Port 17 disabled→designated Jun 27 12:39:54   Port status change port: 17, old: down, new: 10Gfdx Jun 27 12:39:52   Port STP change Port 17 designated→disabled Jun 27 12:39:52   Port status change port: 17, old: 10Gfdx, new: down Jun 27 12:39:51   Port STP change Port 17 disabled→designated Jun 27 12:39:51   Port status change port: 17, old: down, new: 10Gfdx Jun 27 12:39:48   Port STP change Port 17 designated→disabled Jun 27 12:39:48   Port status change port: 17, old: 10Gfdx, new: down Jun 27 12:39:46   Port STP change Port 17 disabled→designated Jun 27 12:39:46   Port status change port: 17, old: down, new: 10Gfdx Jun 27 12:39:44   Port STP change Port 17 designated→disabled Jun 27 12:39:44   Port status change port: 17, old: 10Gfdx, new: down Jun 27 12:39:42   Port STP change Port 17 disabled→designated Jun 27 12:39:42   Port status change port: 17, old: down, new: 10Gfdx Jun 27 12:39:11   UDLD alert port: 17, state: unknown, port_blocked: false Jun 27 12:38:21   Port STP change Port 17 designated→disabled Jun 27 12:38:21   Port status change port: 17, old: 10Gfdx, new: down Jun 27 12:38:21   UDLD alert port: 17, state: unidirectional (outbound fault), port_blocked: true ... View more