Since the port-cvid configuration still has the attributes of a regular untagged VMAN, all of the VLAN and VMAN exclusion and compatibility rules of a regular untagged VMAN port also apply. A list of these rules is contained in “EXOS Selective Q-in-Q”. In ExtremeXOS 21.1, when port-cvid is specified as part of CEP, there can only be one such port-cvid on the port. Any adjacent CEP CVIDs will not be included in the same CVID range.