Load Sharing Using Stp Path Cost - Cisco WS-C2960-24LC-S Software Configuration Manual

Configuring VLAN Trunks
Command
Step 16 interface gigabitethernet 0/1
Step 17 spanning-tree vlan 8-10 port-priority 16
Step 18
exit
Step 19 interface gigabitethernet0/2
Step 20 spanning-tree vlan 3-6 port-priority 16
Step 21 end
Step 22
show running-config
Step 23 copy running-config startup-config

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:
•
•
•
•
Figure 12-3
VLANs 2
VLANs 8
Beginning in privileged EXEC mode, follow these steps to configure the network shown in
Command
Step 1 configure terminal
Step 2
interface gigabitethernet0/1
Step 3
switchport mode trunk
Catalyst 2960 Switch Software Configuration Guide
12-22
12-3, 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
– 4 (path cost 30)
– 10 (path cost 19)
Switch B
Purpose
Define the interface to set the STP port priority, and enter interface
configuration mode.
Assign the port priority of 16 for VLANs 8 through 10.
Return to global configuration mode.
Define the interface to set the STP port priority, and enter interface
configuration mode.
Assign the port priority of 16 for VLANs 3 through 6.
Return to privileged EXEC mode.
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)
Purpose
Enter global configuration mode on Switch A.
Define the interface to be configured as a trunk, and enter interface
configuration mode.
Configure the port as a trunk port.
Chapter 12 Configuring VLANs
Figure 12-3:
OL-8603-04