Configure Encapsulation

Trunk encapsulation dictates the manner in which frames are identified (that is, tagged) on a trunk and defines the VLAN services available. To set the encapsulation type as ISL on the interface, you must first configure the port as trunk. By default, dot1q encapsulation is enabled.

1. Configure the port as the trunk port.

   SEFOS# configure terminal
   SEFOS(config)# interface extreme-ethernet 0/1
   SEFOS(config-if)# switchport mode trunk

2. Set the encapsulation type as ISL.

   SEFOS(config-if)# spanning-tree encap ISL
   SEFOS(config-if)# end

3. Review the port encapsulation type.

   SEFOS# show spanning-tree interface extreme-ethernet 0/1 encapsulationtype
    
   Encapsulation Type is ISL

4. Reset the encapsulation type to the default on the interface.

   SEFOS# configure terminal
   SEFOS(config)# interface extreme-ethernet 0/1
   SEFOS(config-if)# no spanning-tree encap
   SEFOS(config-if)# end