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Catalyst 6000 Family Software Configuration Guide—Releases 6.3 and 6.4
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Chapter 5 Configuring Ethernet VLAN Trunks
Example VLAN Trunk Configurations
To return a port to the default trunk type and mode for that port type, perform this task in privileged
mode:
Example VLAN Trunk Configurations
This section contains example VLAN trunk configurations:
•
ISL Trunk Configuration Example, page 5-9
•
ISL Trunk Over EtherChannel Link Example, page 5-10
•
802.1Q Trunk Over EtherChannel Link Example, page 5-13
•
Load-Sharing VLAN Traffic Over Parallel Trunks Example, page 5-16
ISL Trunk Configuration Example
This example shows how to configure an ISL trunk between two switches and how to limit the allowed
VLANs on the trunk to VLAN 1 and VLANs 520–530.
In this example, port 1/1 on Switch 1 is connected to a Fast Ethernet port on another switch. Both ports
are in their default state, with the trunk mode set to
auto
(for more information, see the
“Default Trunk
Configuration” section on page 5-5
).
Step 1
Configure port 1/1 on Switch 1 as an ISL trunk port by entering the
set trunk
command. By specifying
the
desirable
keyword, the trunk is automatically negotiated with the neighboring port (port 1/2 on
Switch 2). ISL encapsulation is assumed based on the hardware type.
Switch1> (enable)
set trunk 1/1 desirable
Port(s) 1/1 trunk mode set to desirable.
Switch1> (enable) 06/18/1998,12:20:23:DTP-5:Port 1/1 has become isl trunk
06/18/1998,12:20:23:PAGP-5:Port 1/1 left bridge port 1/1.
06/18/1998,12:20:23:PAGP-5:Port 1/1 joined bridge port 1/1.
Switch1> (enable)
Step 2
Check the configuration by entering the
show trunk
command. The Status field in the screen output
indicates that port 1/1 is trunking.
Switch1> (enable)
show trunk 1/1
Port Mode Encapsulation Status Native vlan
-------- ----------- ------------- ------------ -----------
1/1 desirable isl trunking 1
Port Vlans allowed on trunk
-------- ---------------------------------------------------------------------
1/1 1-1005, 1025-4094
Port Vlans allowed and active in management domain
-------- ---------------------------------------------------------------------
1/1 1,521-524
Task
Command
Step 1
Return the port to the default trunking type and
mode for that port type.
clear trunk
mod/port
Step 2
Verify the trunking configuration.
show trunk
[
mod/port
]