A.a native VLAN mismatch on either side of an 802.1Q link
B.BPDU filter configured on a link to another switch
C.Spanning Tree Protocol enabled on both Layer 2 and multilayer switches
D.PortFast enabled on all access and trunk ports

A.Configuration changes made on the port-channel interface apply to all physical ports assigned to the portchannel interface.
B.Configuration changes made on a physical port that is a member of a port-channel interface apply to the port-channel interface.
C.Configuration changes are not permitted with Port Aggregation Protocol； instead， the standardized Link Aggregation Control Protocol should be used if configuration changes are required.
D.The physical port must first be disassociated from the port-channel interface before any configuration changes can be made.