There are three types of EVLAN ports:
External ports. Use these ports to communicate to the outside world. Frames enter and leave the EVLAN through these ports. You can connect devices like routers and shared resources to external ports.
Internal ports. Use these ports to connect to the hosts on the restricted EVLANs.
Inter-switch trunk ports. Use these generic trunk (or hybrid) ports to interconnect multiple switches that belong to the same EVLAN to each other. The isolation behavior of the restricted EVLANs is extended and maintained on all switches belonging to the same EVLAN domain. You can share inter-switch trunk ports with regular VLANs.