Cisco Catalyst 3560-X Series, Software Configuration Manual

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Catalyst 3750-X and 3560-X Switch Software Configuration Guide
OL-25303-03
Chapter 1 Configuring VLANs
Configuring VLAN Trunks
Figure 1-4 Load-Sharing Trunks with Traffic Distributed by Path Cost
Beginning in privileged EXEC mode, follow these steps to configure the network shown in Figure 1-4 :
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 gigabitethernet1/0/1 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 Switch A (for a
Catalyst 3560-X switch) or in the Switch A stack (for a Catalyst 3750-X
switch).
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 gigabitethernet1/0/1 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.
Step 14
Repeat Steps 9 through 13 on the other configured trunk interface on
Switch A, and set the spanning-tree path cost to 30 for VLANs 8, 9, and
10.
Step 15 exit Return to privileged EXEC mode.
Step 16 show running-config Verify your entries. In the display, verify that the path costs are set
correctly for both trunk interfaces.
Step 17 copy running-config startup-config (Optional) Save your entries in the configuration file.