Spanning Tree Protocol | 1051Configuring Interfaces for Layer 2 ModeAll interfaces on all switches that will participate in Spanning Tree must be in Layer 2 mode and enabled.Figure 52-1. Example of Configuring Interfaces for Layer 2 ModeTo configure the interfaces for Layer 2 and then enable them:Verify that an interface is in Layer 2 mode and enabled using the show config command from INTERFACEmode.Figure 52-2. Verifying Layer 2 ConfigurationStep Task Command Syntax Command Mode1 If the interface has been assigned an IP address,remove it.no ip address INTERFACE2 Place the interface in Layer 2 mode. switchport INTERFACE3 Enable the interface. no shutdown INTERFACER1 R2R31/33/1 3/23/43/31/41/1 1/22/12/2 2/3 2/4R1(conf)# int range gi 1/1 - 4R1(conf-if-gi-1/1-4)# switchportR1(conf-if-gi-1/1-4)# no shutdownR1(conf-if-gi-1/1-4)#show config!interface GigabitEthernet 1/1no ip addressswitchportno shutdown!interface GigabitEthernet 1/2no ip addressswitchportno shutdown!interface GigabitEthernet 1/3no ip addressswitchportno shutdown!interface GigabitEthernet 1/4no ip addressswitchportno shutdownFTOS(conf-if-gi-1/1)#show config!interface GigabitEthernet 1/1no ip addressswitchportno shutdownFTOS(conf-if-gi-1/1)#Indicates that the interface is in Layer 2 mode
