Cisco Catalyst 3550 series Software Configuration Manual page 290

Configuring VLAN Trunks
In Figure
as follows:
•
•
•
•
Figure 12-4 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
Step 3
switchport trunk encapsulation
{isl | dot1q | negotiate}
Step 4
switchport mode trunk
Step 5 exit
Step 6
Step 7
end
Step 8 show running-config
Step 9 show vlan
Step 10
configure terminal
Step 11
interface fastethernet 0/1
Catalyst 3550 Multilayer Switch Software Configuration Guide
12-26
12-4, 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
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.
Configure the port to support ISL or 802.1Q encapsulation.
You must configure each end of the link with the same encapsulation
type.
Configure the port as a trunk port.
The trunk defaults to ISL trunking.
Return to global configuration mode.
Repeat Steps 2 through 4 on Switch 1 interface Fast Ethernet 0/2.
Return to privileged EXEC mode.
Verify your entries.
In the display, make sure that interfaces Fast Ethernet 0/1 and Fast
Ethernet 0/2 are configured as trunk ports.
When the trunk links come up, Switch 1 receives the VTP information
from the other switches. Verify that Switch 1 has learned the VLAN
configuration.
Enter global configuration mode.
Enter interface configuration mode, and define Fast Ethernet port 0/1 as
the interface to set the STP cost.
Chapter 12 Configuring VLANs
Figure 12-4:
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