This afternoon, with no changes to the network, a switch suddenly started dropping off lots of connections. These connections would come back up a few minutes later, then another area connected to the switch would drop off. This is an older 4006 chassis switch which could in and of itself be a problem but I'm looking to see what else you all would look for in trying to find a root cause. Switch is connected via ports 1/1 and 1/2 in an etherchannel to a VSS core 1/1/42 and 2/1/42. Both sides are up and working however the CPU on the switch will spike up to 99% and that's when CRC errors start to hit the VSS core on one of those interfaces and end points start dropping off. We tried new transceivers and SFP's on each side of the link, same result. When we tried swapping the fiber patch cables on the access switch the CRC errors did not follow the fiber cables they stayed with port 1/2 on the access switch. So port 1/2 on the supervisor module looks like the culprit. We actually tried to create a new member of the ethernet channel by taking a fiber media converter to cat5 and make that a member of the port-channel but when we plugged it in you couldn't even reach the switch. I'm guessing that's unrelated and a problem with the media converter. As of right now we have left it in a state of only one fiber cable running to one side of the VSS core (1/1 Access Switch -- 2/1/42). I've sent some info into TAC and they are looking into the situation but does anyone else have any commands I could run or some troubleshooting I could look into in the meantime?