Type of Interface Possible Modes Requires Creation Default StatePort Channel Layer 2Layer 3Yes Shutdown (disabled)VLAN Layer 2Layer 3Yes, except for thedefault VLAN.No shutdown (active forLayer 2)Shutdown (disabled forLayer 3 )Configuring Layer 2 (Data Link) ModeDo not configure switching or Layer 2 protocols such as spanning tree protocol (STP) on an interfaceunless the interface has been set to Layer 2 mode.To set Layer 2 data transmissions through an individual interface, use the following command.• Enable Layer 2 data transmissions through an individual interface.INTERFACE modeswitchportExample of a Basic Layer 2 Interface ConfigurationDell(conf-if)#show config!interface Port-channel 1no ip addressswitchportno shutdownDell(conf-if)#Configuring Layer 2 (Interface) ModeTo configure an interface in Layer 2 mode, use the following commands.• Enable the interface.INTERFACE modeno shutdown• Place the interface in Layer 2 (switching) mode.INTERFACE modeswitchportTo view the interfaces in Layer 2 mode, use the show interfaces switchport command in EXECmode.Configuring Layer 3 (Network) ModeWhen you assign an IP address to a physical interface, you place it in Layer 3 mode.To enable Layer 3 mode on an individual interface, use the following commands. In all interface typesexcept VLANs, the shutdown command prevents all traffic from passing through the interface. In VLANs,the shutdown command prevents Layer 3 traffic from passing through the interface. Layer 2 traffic isunaffected by the shutdown command. One of the interfaces in the system must be in Layer 3 modebefore you configure or enter a Layer 3 protocol mode (for example, OSPF).Interfaces 381
