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Cisco ME 3400 Ethernet Access Switch Software Configuration Guide
OL-9639-06
Chapter 11 Configuring VLANs Configuring VLAN Trunks
Follow the same steps on Switch B to configure the trunk port for Trunk 1 with a spanning-tree port
priority of 16 for VLANs 8 through 10, and the configure trunk port for Trunk 2 with a spanning-tree
port priority of 16 for VLANs 3 through 6.
Load Sharing Using STP Path Cost
You can configure parallel trunks to share VLAN traffic by setting different path costs on a trunk and
associating the path costs with different sets of VLANs, blocking different ports for different VLANs.
The VLANs keep the traffic separate and maintain redundancy in the event of a lost link.
In Figure 11-4, Trunk ports 1 and 2 are configured as 100Base-T ports. These VLAN path costs are
assigned:
• VLANs 2 through 4 are assigned a path cost of 30 on Trunk port 1.
• VLANs 8 through 10 retain the default 100Base-T path cost on Trunk port 1 of 19.
• VLANs 8 through 10 are assigned a path cost of 30 on Trunk port 2.
• VLANs 2 through 4 retain the default 100Base-T path cost on Trunk port 2 of 19.
Step 15 show interfaces gigabitethernet 0/1
switchport Verify the port configuration.
Step 16 configure terminal Enter global configuration mode.
Step 17 interface gigabitethernet 0/2 Define the interface to be configured as the Trunk 2 interface, and
enter interface configuration mode.
Step 18 port-type {nni | eni} Configure the interface as an NNI or ENI. UNIs do not support STP.
If you configure the port as an ENI, you must also enable STP on the
port by entering the spanning-tree interface configuration command.
Step 19 switchport mode trunk Configure the port as a trunk port.
Step 20 spanning-tree vlan 3-6 port-priority 16 Assign the port priority of 16 for VLANs 3 through 6 on Trunk 2.
Step 21 end Return to privileged EXEC mode.
Step 22 show interfaces gigabitethernet 0/2
switchport Verify the port configuration.
Step 23 show running-config Verify your entries.
Step 24 copy running-config startup-config (Optional) Save your entries in the configuration file.
Command Purpose