Default Layer 2 Ethernet Interface Vlan Configuration; Configuring An Ethernet Interface As A Trunk Port - Cisco Catalyst 2360 Software Configuration Manual

Configuring VLAN Trunks
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Default Layer 2 Ethernet Interface VLAN Configuration

Table 9-5
Table 9-5
Feature
Interface mode
Trunk encapsulation
Allowed VLAN range
VLAN range eligible for pruning
Default VLAN (for access ports)
Native VLAN (for IEEE 802.1Q trunks) VLAN 1

Configuring an Ethernet Interface as a Trunk Port

Because trunk ports send and receive VTP advertisements, to use VTP you must ensure that at least one
trunk port is configured on the switch and that this trunk port is connected to the trunk port of a second
switch. Otherwise, the switch cannot receive any VTP advertisements.
These sections contain this configuration information:
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By default, an interface is in Layer 2 mode. The default mode for Layer 2 interfaces is switchport mode
Note
dynamic auto. If the neighboring interface supports trunking and is configured to allow trunking, the
link is a Layer 2 trunk or, if the interface is in Layer 3 mode, it becomes a Layer 2 trunk when you enter
the switchport interface configuration command. The Catalyst 2360 switch supports only IEEE 802.1q
trunking.
Catalyst 2360 Switch Software Configuration Guide
9-16
Make sure the native VLAN for an IEEE 802.1Q trunk is the same on both ends of the trunk link. If
the native VLAN on one end of the trunk is different from the native VLAN on the other end,
spanning-tree loops might result.
Disabling spanning tree on the native VLAN of an IEEE 802.1Q trunk without disabling spanning
tree on every VLAN in the network can potentially cause spanning-tree loops. We recommend that
you leave spanning tree enabled on the native VLAN of an IEEE 802.1Q trunk or disable spanning
tree on every VLAN in the network. Make sure your network is loop-free before disabling spanning
tree.
shows the default Layer 2 Ethernet interface VLAN configuration.
Default Layer 2 Ethernet Interface VLAN Configuration
Interaction with Other Features, page 9-17
Defining the Allowed VLANs on a Trunk, page 9-18
Changing the Pruning-Eligible List, page 9-19
Configuring the Native VLAN for Untagged Traffic, page 9-20
Default Setting
switchport mode dynamic auto
switchport trunk encapsulation negotiate
VLANs 1 to 4094
VLANs 2 to 1001
VLAN 1
Chapter 9 Configuring VLANs
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