Define VLANs Allowed on Trunk Link

1. First navigate to the interface for the port or port-channel. 
 config t
int e1/1 
 Below for a port-channel. 
 config t
int port-channel 1 
 2. Ensure the port/port-channel is a trunk. 
 switchport mode trunk 
 3. To add a VLAN, use the following command to add the VLANs necessary. 
 switchport trunk allowed vlan add 7,10,20 
 4. To remove a VLAN, use the following command. 
 switchport trunk allowed vlan remove 5-10,12