Changing The Pruning-Eligible List; Configuring The Native Vlan For Untagged Traffic - Cisco WS-C2955T-12 Software Manual

How VLAN Trunks Work

Changing the Pruning-Eligible List

The pruning-eligible list applies only to trunk ports. Each trunk port has its own eligibility list. VTP
Pruning must be enabled for this procedure to take effect. The
page 8-19
Beginning in privileged EXEC mode, follow these steps to remove VLANs from the pruning-eligible
list on a trunk port:
Command
Step 1
configure terminal
Step 2
interface interface-id
Step 3
switchport trunk pruning vlan
remove vlan-id
Step 4 exit
Step 5 show interface interface-id
switchport

Configuring the Native VLAN for Untagged Traffic

A trunk port configured with 802.1Q tagging can receive both tagged and untagged traffic. By default,
the switch forwards untagged traffic with the native VLAN configured for the port. The native VLAN
is VLAN 1 by default. For information about 802.1Q configuration issues, see the
Configuration Considerations" section on page
Note The native VLAN can be assigned any VLAN ID, and it is not dependent on the management VLAN.
Beginning in privileged EXEC mode, follow these steps to configure the native VLAN on an 802.1Q
trunk:
Command
Step 1
configure terminal
Step 2 interface interface-id
Step 3 switchport trunk native vlan vlan-id Configure the VLAN that is sending and receiving untagged traffic on the
Step 4 show interface interface-id
switchport
If a packet has a VLAN ID that is the same as the outgoing port native VLAN ID, the packet is sent
untagged; otherwise, the switch sends the packet with a tag.
Catalyst 2900 Series XL and Catalyst 3500 Series XL Software Configuration Guide
8-30
describes how to enable VTP pruning.
Purpose
Enter global configuration mode.
Enter interface configuration mode, and select the trunk port for which
VLANs should be pruned.
Enter the VLANs to be removed from the pruning-eligible list.
Separate nonconsecutive VLAN IDs with a comma and no spaces; use a
hyphen to designate a range of IDs. Valid IDs are from 2 to 1001.
VLANs that are pruning-ineligible receive flooded traffic.
Return to privileged EXEC mode.
Verify your settings.
Purpose
Enter global configuration mode.
Enter interface configuration mode, and define the interface that is
configured as the 802.1Q trunk.
trunk port.
Valid IDs are from 1 to 1001.
Verify your settings.
"Enabling VTP Pruning" section on
8-26.
Chapter 8 Configuring VLANs
"IEEE 802.1Q
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