Load Sharing Using Stp Path Cost - Cisco ME 3400G-2CS - Ethernet Access Switch Software Configuration Manual

Chapter 11 Configuring VLANs
Command
Step 17 interface gigabitethernet 0/2
Step 18
port-type nni
Step 19
switchport mode trunk
Step 20 spanning-tree vlan 3-6 port-priority 16
Step 21
end
Step 22
show interfaces gigabitethernet 0/2
switchport
Step 23
show running-config
Step 24 copy running-config startup-config
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
assigned:
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•
•
•
Figure 11-4
VLANs 2 – 4 (path cost 30)
VLANs 8 – 10 (path cost 19)
78-17058-01
11-4, Trunk ports 1 and 2 are configured as 100Base-T ports. These VLAN path costs are
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.
Load-Sharing Trunks with Traffic Distributed by Path Cost
Trunk port 1
Switch B
Purpose
Define the interface to be configured as the Trunk 2 interface, and
enter interface configuration mode.
Configure the interface as an NNI.
Configure the port as a trunk port.
Assign the port priority of 16 for VLANs 3 through 6 on Trunk 2.
Return to privileged EXEC mode.
Verify the port configuration.
Verify your entries.
(Optional) Save your entries in the configuration file.
Switch A
Trunk port 2
VLANs 8 – 10 (path cost 30)
VLANs 2 – 4 (path cost 19)
Cisco ME 3400 Ethernet Access Switch Software Configuration Guide
Configuring VLAN Trunks
11-21