Load Sharing Using Stp Path Cost - Cisco 3020 - Catalyst Blade Switch Configuration Manual

Chapter 10 Configuring VLANs
Command
Step 6 show vlan
Step 7 configure terminal
Step 8 interface gigabitethernet 0/1
Step 9
switchport trunk encapsulation {isl |
dot1q | negotiate}
Step 10 switchport mode trunk
Step 11
end
Step 12 show interfaces gigabitethernet 0/1
switchport
Step 13
Step 14
Step 15
show vlan
Step 16
configure terminal
Step 17 interface gigabitethernet 0/1
Step 18 spanning-tree vlan 8-10 port-priority 16
Step 19 exit
Step 20
interface gigabitethernet0/2
Step 21
spanning-tree vlan 3-6 port-priority 16
Step 22 end
Step 23 show running-config
Step 24
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:
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OL-8915-01
10-4, 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.
Purpose
Verify that the VLANs exist in the database on Switch A.
Enter global configuration mode.
Define the interface to be configured as a trunk, and enter interface
configuration mode.
Configure the port to support ISL or IEEE 802.1Q encapsulation or to
negotiate with the neighboring interface. You must configure each end
of the link with the same encapsulation type.
Configure the port as a trunk port.
Return to privileged EXEC mode.
Verify the VLAN configuration.
Repeat Steps 7 through 11 on Switch A for a second port in the switch.
Repeat Steps 7 through 11 on Switch B to configure the trunk ports
that connect to the trunk ports configured on Switch A.
When the trunk links come up, VTP passes the VTP and VLAN
information to Switch B. Verify that Switch B has learned the VLAN
configuration.
Enter global configuration mode on Switch A.
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.
Cisco Catalyst Blade Switch 3020 for HP Software Configuration Guide
Configuring VLAN Trunks
10-23