Filter
Top Products
13-27
Catalyst 3750 Switch Software Configuration Guide
OL-8550-09
Chapter 13 Configuring VLANs
Configuring VLAN Trunks
In Figure 13-4, Trunk ports 1 and 2 are configured as 100BASE-T ports. These VLAN path costs 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.
Figure 13-4 Load-Sharing Trunks with Traffic Distributed by Path Cost
Beginning in privileged EXEC mode, follow these steps to configure the network shown in Figure 13-4:
90573
Switch A
Switch B
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)
Command Purpose
Step 1
configure terminal Enter global configuration mode on Switch A.
Step 2
interface interface-id_1 Define the interface to be configured as a trunk, and enter interface
configuration mode.
Step 3
switchport trunk encapsulation
{isl | dot1q | negotiate}
Configure the port to support ISL or IEEE 802.1Q encapsulation. You
must configure each end of the link with the same encapsulation type.
Step 4
switchport mode trunk Configure the port as a trunk port. The trunk defaults to ISL trunking.
Step 5
exit Return to global configuration mode.
Step 6
Repeat Steps 2 through 5 on a second interface in the Switch A stack.
Step 7
end Return to privileged EXEC mode.
Step 8
show running-config Verify your entries. In the display, make sure that the interfaces are
configured as trunk ports.
Step 9
show vlan When the trunk links come up, Switch A receives the VTP information
from the other switches. Verify that Switch A has learned the VLAN
configuration.
Step 10
configure terminal Enter global configuration mode.
Step 11
interface interface-id_1 Define the interface on which to set the STP cost, and enter interface
configuration mode.
Step 12
spanning-tree vlan 2-4 cost 30 Set the spanning-tree path cost to 30 for VLANs 2 through 4.
Step 13
end Return to global configuration mode.