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Catalyst 2900 Series XL and Catalyst 3500 Series XL Software Configuration Guide
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Chapter 8 Configuring VLANs
Overlapping VLANs and Multi-VLAN Ports
Figure 8-2
Two VLANs Sharing a Port Connected to a Router
Caution
To avoid unpredictable STP behavior and a loss of connectivity, do not connect multi-VLAN ports to
hubs or switches. Connect multi-VLAN ports to routers or servers.
Beginning in privileged EXEC mode, follow these steps to assign ports for multi-VLAN membership:
VLAN 42
12516
Cisco router
VLAN 77
Ports in static-access
mode
Port in multi-VLAN mode
Command
Purpose
Step 1
configure terminal
Enter global configuration mode.
Step 2
interface interface
Enter interface configuration mode, and enter the port to be added to the
VLAN.
Step 3
switchport mode multi
Enter the VLAN membership mode for multi-VLAN ports.
Step 4
switchport multi vlan vlan-list
Assign the port to more than one VLAN.
Separate nonconsecutive VLAN IDs with a comma; use a hyphen to
designate a range of IDs.
Configuring a switch port for multi-VLAN mode causes VTP to transition to
transparent mode, which disables VTP.
Step 5
end
Return to privileged EXEC mode.
Step 6
show interface interface-id
switchport
Verify your entries.