Load Sharing Using Stp Path Cost - Cisco Catalyst 2928 Software Configuration Manual

Configuring VLAN Trunks
Command
Step 14
show vlan
Step 15
configure terminal
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 13-3
VLANs 2
VLANs 8
Catalyst 2928 Switch Software Configuration Guide
13-20
13-3, 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
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.
Switch A
Trunk port 2
VLANs 8 – 10 (path cost 30)
VLANs 2 – 4 (path cost 19)
Chapter 13 Configuring VLANs
OL-23389-01