Cisco WS-C2960S-24PD-L Software Guide - Page 256

Load Sharing Using STP Chapter 8 Configuring VLANs Command Step 16 interface fa0/1 Step 17 Step 18 Step 19 spanning-tree vlan 8 9 10 port-priority 10 end interface fa0/2 Step 20 Step 21 Step 22 spanning-tree vlan 3 4 5 6 port priority 10 exit show running-config Purpose Enter interface configuration mode, and define the interface to set the STP port priority. Assign the port priority of 10 for VLANs 8, 9, and 10. 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 VLANs 3, 4, 5, and 6. Return to privileged EXEC mode. Verify your entries. 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 8-6, trunk ports 1 and 2 are 100BASE-T ports. The path costs for the VLANs are assigned as follows: • 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. Figure 8-6 Load-Sharing Trunks with Traffic Distributed by Path Cost Switch 1 Trunk port 1 VLANs 2 - 4 (path cost 30) VLANs 8 - 10 (path cost 19) Trunk port 2 VLANs 8 - 10 (path cost 30) VLANs 2 - 4 (path cost 19) 16591 Switch 2 8-34 Catalyst 2900 Series XL and Catalyst 3500 Series XL Software Configuration Guide 78-6511-08