The VLAN which the corresponding instance of
vlanTrunkMappingFromVlan will be mapped to.
Agent returns inconsistentValue if this VLAN
exists in the device.
Agent returns inconsistentValue if this VLAN is a
reserved VLAN and the value of corresponding
instance of vlanTrunkMappingType is
reservedToNonReserved(1).
Agent returns inconsistentValue if this VLAN is
not a valid ISL VLAN and the value of
corresponding instance of vlanTrunkMappingType
is dot1qToisl(2).