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Catalyst 6500 Series Switch Software Configuration Guide—Release 8.7
OL-8978-04
Chapter 6 Configuring EtherChannel
Configuring an EtherChannel Using PAgP
The EtherChannel VLAN cost feature provides load balancing of VLAN traffic across multiple channels
that are configured with trunking.
You enter the
set spantree channelvlancost
command to set the initial spanning-tree costs for all
VLANs in the channel. The
set spantree channelvlancost
command provides an alternate cost for some
of the VLANs in the channel (assuming that you are trunking across the channel). This command allows
you to have up to two different spanning-tree costs assigned per channel; some VLANs in the channel
can have the “vlancost” while the remaining VLANs in the channel have the “cost.”
The
set spantree channelvlancost
command creates a “set spantree portvlancost” entry to the
configuration file for each port in the channel. After you enter the
set spantree channelvlancost
command, you must enter the
set spantree portvlancost
command for at least one port in the channel,
specifying the VLAN or VLANs that you want associated with each port. This example shows what
occurs when you enter each command:
Console> (enable)
set spantree channelvlancost 856 10
Port(s) 3/47-48 vlan cost are updated to 16.
Channel 856 vlancost is set to 10.
These commands are added to the configuration file:
•
set spantree portvlancost 3/47 cost 16
•
set spantree portvlancost 3/48 cost 16
To add the desired VLANs to the above created commands, enter this command:
Console> (enable)
set spantree portvlancost 3/47 cost 16 1-1005
Port 3/47 VLANs 1025-4094 have path cost 19.
Port 3/47 VLANs 1-1005 have path cost 16.
Port 3/48 VLANs 1-1005 have path cost 16.
To set the EtherChannel VLAN cost, perform this task in privileged mode:
This example shows how to set the EtherChannel VLAN cost for channel ID 856:
Console> (enable)
show channel group 22
Admin Port Status Channel Channel
group Mode id
----- ----- ---------- --------- --------
22 1/1 notconnect on 856
22 1/2 connected on 856
Admin Port Device-ID Port-ID Platform
group
----- ----- ------------------------------- ------------------------- ----------
22 1/1
22 1/2 066510644(cat26-lnf(NET25)) 2/1 WS-C6009
Console> (enable)
Task
Command
Step 1
Use the administrative group number to display
the EtherChannel ID.
show channel group
admin_group
or
show lacp-channel group
admin_key
Step 2
Use the EtherChannel ID to set the EtherChannel
VLAN cost.
set spantree channelvlancost
channel_id
cost
Step 3
Configure the port cost for the desired VLANs on
each port.
set spantree portvlancost
{
mod/port
}
[
cost
cost
]
[
vlan_list
]
