5-8
Catalyst 6000 Family Software Configuration Guide—Releases 6.3 and 6.4
78-13315-02
Chapter 5 Configuring Ethernet VLAN Trunks
Configuring a Trunk Link
Note
When you first configure a port as a trunk, entering the
set trunk
command always adds all VLANs
to the allowed VLAN list for the trunk, even if you specify a VLAN range (any specified VLAN
range is ignored). To modify the allowed VLANs list, use a combination of the
clear trunk
and
set
trunk
commands to specify the allowed VLANs.
To define the allowed VLAN list for a trunk port, perform this task in privileged mode:
This example shows how to define the allowed VLANs list to allow VLANs 1–100, VLANs 500–1005,
and VLAN 2500 on trunk port 1/1 and how to verify the allowed VLAN list for the trunk:
Console> (enable)
clear trunk 1/1 101-499
Removing Vlan(s) 101-499 from allowed list.
Port 1/1 allowed vlans modified to 1-100,500-1005.
Console> (enable)
set trunk 1/1 2500
Adding vlans 2500 to allowed list.
Port(s) 1/1 allowed vlans modified to 1-100,500-1005,2500.
Console> (enable)
show trunk 1/1
Port Mode Encapsulation Status Native vlan
-------- ----------- ------------- ------------ -----------
1/1 desirable isl trunking 1
Port Vlans allowed on trunk
-------- ---------------------------------------------------------------------
1/1 1-100, 500-1005,2500
Port Vlans allowed and active in management domain
-------- ---------------------------------------------------------------------
1/1 1,521-524
Port Vlans in spanning tree forwarding state and not pruned
-------- ---------------------------------------------------------------------
1/1 1,521-524
Console> (enable)
Disabling a Trunk Port
To turn off trunking on a port, perform this task in privileged mode:
Task
Command
Step 1
Remove VLANs from the allowed VLANs list for
a trunk.
clear trunk
mod/port
vlans
Step 2
(Optional) Add specific VLANs to the allowed
VLANs list for a trunk.
set trunk
mod/port
vlans
Step 3
Verify the allowed VLAN list for the trunk.
show trunk
[
mod/port
]
Task
Command
Step 1
Turn off trunking on a port.
set trunk
mod/port
off
Step 2
Verify the trunking configuration.
show trunk
[
mod/port
]