VLAN Trunking over Etherchannel with Cat 4006 Sup III

[umriguy]

I have 3 Catalyst 4006 Sup III Switches.

Switch A has two Gigabit ports connected to Switch B
Switch A has two Gigabit ports connected to Switch C

VLAN Trunking is configured on each of the Gigabit ports
!
! Current SwitchA coniguration
!
interface GigabitEthernet1/1
description trunk to switchB port GI1/1
switchport trunk encapsulation isl
switchport trunk native vlan 116
switchport mode dynamic desirable
no snmp trap link-status
!
interface GigabitEthernet1/2
description trunk to switchC port GI1/1
switchport trunk encapsulation isl
switchport trunk native vlan 116
switchport mode dynamic desirable
no snmp trap link-status
!
interface GigabitEthernet2/1
description trunk to switchB port GI1/2
switchport trunk encapsulation isl
switchport trunk native vlan 116
switchport mode dynamic desirable
no snmp trap link-status
!
interface GigabitEthernet2/2
description trunk to switchC port GI1/2
switchport trunk encapsulation isl
switchport trunk native vlan 116
switchport mode dynamic desirable
no snmp trap link-status

!
! Current SwitchB or SwitchC configuration
!
interface GigabitEthernet1/1
description trunk to SwitchA port GI1/1
switchport access vlan 116
switchport trunk encapsulation isl
switchport trunk native vlan 116
no snmp trap link-status
!
interface GigabitEthernet1/2
description trunk to SwitchA port GI2/1
switchport access vlan 116
switchport trunk encapsulation isl
switchport trunk native vlan 116
no snmp trap link-status

Currently this configuration works fine, but the connectivity is limited to 1GBit between switches with the second connection disabled by STP. What I would like to do is to create an Etherchannel with the two Gigabit links and trunk my VLAN traffic over the 'channel'. We use VLANs 1,2,116,118 only. I've gone thru much of the documentation ... and I'm a bit unsure of the necessary IOS commands. Here's what I have, feel free to poke holes into it!

!
! Proposed SwitchA Config
!
Interface Port-Channel 10
No ip address
switchport trunk encapsulation dot1q
switchport trunk allowed vlan remove 2-1001
switchport trunk allowed vlan add 2,116,118
switchport mode trunk
end

Interface Port-Channel 11
no ip address
switchport trunk encapsulation dot1q
switchport trunk allowed vlan remove 2-1001
switchport trunk allowed vlan add 2,116,118
switchport mode trunk
end

Interface GI1/1
no ip address
channel-group 10 mode desirable
switchport mode access/trunk???
end

Interface GI2/1
no ip address
channel-group 10 mode desirable
switchport mode access/trunk???
end

Interface GI1/2
no ip address
channel-group 11 mode desirable
switchport mode access/trunk???
end

Interface GI2/2
no ip address
channel-group 11 mode desirable
switchport mode access/trunk???
end

!
!Proposed SwitchB Config
!(SwitchC sub 11 for the port-channel group)
!
interface port-channel 10
no ip address
switchport trunk encapsulation dot1q
switchport trunk allowed vlan remove 2-1001
switchport trunk allowed vlan add 2,116,118
switchport mode trunk
end

Port-channel load-balance src-dst-ip

Interface GI1/1
no ip address
channel-group 10 mode desirable
switchport mode access/trunk???
end
Interface GI1/2
no ip address
channel-group 10 mode desirable
switchport mode access/trunk???
end
!

I'm a bit confused about what "switchport mode" an individual interface needs to be in if it is configured as part of a channel-group... where the channel-group has been defined as a trunk.

Should the channel-group mode be 'desirable' on both ends?

Should the individual interfaces be set to switchport mode "access" or "trunk"?

Can anyone share a similar 'real life' IOS configuration similar to this one?

Many thanks in advance!

-umriguy

 

[ADB100]

Each of the Physical Interfaces in the Channel must have the same configuration as the 'Parent' Channel Interface. I think that if the channel has been created first without any additional configuration (i.e. you just do the 'channel-group 10 mode desirable'). The channel will (should) form, after the channel has formed (and STP has settled down) you should then be able to apply the Trunking configuration to the 'Parent' Channel interface, this should then be pushed down to the physical interfaces and appear in the configuration.
Alternatively youo could just apply the configuration changes to a range of interfaces; including the Port-Channel and the physical interfaces. This will ensure that the configuration is applied to all interfaces, whether they are up or down.

If this is a production environment I would arrange some down-time to make the changes.

Andy