There are various reasons for the interface to go into errdisable. The reason can be:
Duplex mismatch
Port channel misconfiguration
BPDU guard violation
UniDirectional Link Detection (UDLD) condition
Late-collision detection
Link-flap detection
Security violation
Port Aggregation Protocol (PAgP) flap
Layer 2 Tunneling Protocol (L2TP) guard
DHCP snooping rate-limit
Incorrect GBIC / Small Form-Factor Pluggable (SFP) module or cable
Address Resolution Protocol (ARP) inspection
Inline power
it will be::A (correct)
12.09.2016 17:38, mik:
Try it with the real switches: set manual half duplex from one side and full from other... You see CRC error but link will be UP and work..
Port security or BPDU guard can put interface into err-disable state...