Load Sharing Using Stp Path Cost - Cisco Catalyst 2950 Software Configuration Manual

Configuring VLAN Trunks
Command
Step 20
exit
Step 21
interface fastethernet0/2
Step 22 spanning-tree vlan 3 port-priority 10
Step 23 spanning-tree vlan 4 port-priority 10
Step 24
spanning-tree vlan 5 port-priority 10
Step 25
spanning-tree vlan 6 port-priority 10
Step 26 end
Step 27 show running-config
Step 28
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. The VLANs keep the traffic separate. Because
no loops exist, STP does not disable the ports, and redundancy is maintained in the event of a lost link.
In Figure
as follows:
•
•
•
•
Figure 13-4 Load-Sharing Trunks with Traffic Distributed by Path Cost
VLANs 2 – 4 (path cost 30)
VLANs 8 – 10 (path cost 19)
Beginning in privileged EXEC mode, follow these steps to configure the network shown in
Command
Step 1
configure terminal
Step 2 interface fastethernet 0/1
Catalyst 2950 Desktop Switch Software Configuration Guide
13-28
13-4, Trunk ports 1 and 2 are 100BASE-T ports. The path costs for the VLANs 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.
Trunk port 1
Switch 2
Purpose
Return to global configuration mode.
Enter interface configuration mode, and define the interface to set the
STP port priority.
Assign the port priority of 10 for VLAN 3.
Assign the port priority of 10 for VLAN 4.
Assign the port priority of 10 for VLAN 5.
Assign the port priority of 10 for VLAN 6.
Return to privileged EXEC mode.
Verify your entries.
(Optional) Save your entries in the configuration file.
Switch 1
Trunk port 2
VLANs 8 – 10 (path cost 30)
VLANs 2 – 4 (path cost 19)
Purpose
Enter global configuration mode on Switch 1.
Enter interface configuration mode, and define Fast Ethernet port 0/1 as
the interface to be configured as a trunk.
Chapter 13 Configuring VLANs
Figure 13-4:
78-11380-04