CCNA Complete Guide 2nd Edition.pdf - Cisco Learning Home

switchport trunk encapsulation and switchport mode trunk Configuration
- Below shows the configuration sequence of VLAN trunking on a Fast Ethernet interface.
The VLAN trunking encapsulation must be configured (with the switchport trunk
encapsulation interface subcommand) prior to configuring a trunking interface with the
switchport mode trunk interface subcommand.
Switch#sh run int fa0/1
Building configuration...
Current configuration : 68 bytes
!
interface FastEthernet0/1
switchport mode dynamic desirable
end
Switch#
Switch#sh int fa0/1 trunk
Port Mode Encapsulation Status Native vlan
Fa0/12 desirable negotiate other 1
Port Vlans allowed on trunk
Fa0/12 none
Port Vlans allowed and active in management domain
Fa0/12 none
Port Vlans in spanning tree forwarding state and not pruned
Fa0/12 none
Switch#
Switch#conf t
Enter configuration commands, one per line. End with CNTL/Z.
Switch(config)#int fa0/1
Switch(config-if)#switchport mode trunk
Command rejected: An interface whose trunk encapsulation is "Auto" can not
be configured to "trunk" mode.
Switch(config-if)#
Switch(config-if)#switchport trunk encapsulation ?
dot1q Interface uses only 802.1q trunking encapsulation when trunking
isl Interface uses only ISL trunking encapsulation when trunking
negotiate Device will negotiate trunking encapsulation with peer on
interface
Switch(config-if)#switchport trunk encapsulation dot1q
Switch(config-if)#switchport mode trunk
Switch(config-if)#^Z
Switch#
255
Copyright © 2008 Yap Chin Hoong
yapchinhoong@hotmail.com