Active Porchannel - Adding new member fails

[johnelliot6]

Hi,

Have an active portchan that currently has one 100Mb port - Trying to add second port, I am getting the following in the logs:

Jul 27 22:17:44.744 GMT+10: %EC-5-CANNOT_BUNDLE2: Fa0/20 is not compatible with Fa0/21 and will be suspended (trunk mode of Fa0/20 is trunk, Fa0/21 is dynamic)

Both Fa0/20 + Fa0/21 are configured the same(20 currently shutdown):

interface FastEthernet0/20

description trunk to esw02-bne

switchport trunk allowed vlan 1,11,12,14,30,35,68,99,100,103,104,106-108,112

switchport trunk allowed vlan add 113,115,120-123,129,132-136,138,156,158,160

switchport trunk allowed vlan add 206,289,311,312,340,345,377-396,398,399,402

switchport trunk allowed vlan add 422,444,472,473,475,478-488,492,493,497,498

switchport trunk allowed vlan add 500,546,590,591,700,801-806,808,809,811-815

switchport trunk allowed vlan add 865,866,868,869,957,970,973,974,978,987,1829

switchport trunk allowed vlan add 2501,2506,2516,2518-2525

switchport mode trunk

switchport nonegotiate

shutdown

mls qos trust dscp

no cdp enable

channel-group 2 mode on

spanning-tree bpdufilter enable

spanning-tree guard root

interface FastEthernet0/21
description FEC_TO_ESW02_P2
switchport trunk allowed vlan 1,11,12,14,30,35,68,99,100,103,104,106-108,112
switchport trunk allowed vlan add 113,115,120-123,129,132-136,138,156,158,160
switchport trunk allowed vlan add 206,289,311,312,340,345,377-396,398,399,402
switchport trunk allowed vlan add 422,444,472,473,475,478-488,492,493,497,498
switchport trunk allowed vlan add 500,546,590,591,700,801-806,808,809,811-815
switchport trunk allowed vlan add 865,866,868,869,957,970,973,974,978,987,1829
switchport trunk allowed vlan add 2501,2506,2516,2518-2525
switchport mode trunk
switchport nonegotiate
mls qos trust dscp
no cdp enable
channel-group 2 mode on
spanning-tree bpdufilter enable
spanning-tree guard root

And switchports are not reporting as "dynamic":

#sh int fastEthernet 0/20 switchport
Name: Fa0/20
Switchport: Enabled
Administrative Mode: trunk
Operational Mode: down (suspended member of bundle Po2)
Administrative Trunking Encapsulation: dot1q
Negotiation of Trunking: Off
Access Mode VLAN: 1 (default)
Trunking Native Mode VLAN: 1 (default)
Voice VLAN: none

#sh int fastEthernet 0/21 switchport
Name: Fa0/21
Switchport: Enabled
Administrative Mode: trunk
Operational Mode: trunk (member of bundle Po2)
Administrative Trunking Encapsulation: dot1q
Operational Trunking Encapsulation: dot1q
Negotiation of Trunking: Off
Access Mode VLAN: 1 (default)
Trunking Native Mode VLAN: 1 (default)
Voice VLAN: none

The switch causing the problems is C2950G-24-EI - Is this a known bug...any suggestions on work-around?

Thanks in advance.

[CiscoIsInYou]

Hello John,

I guess you created the Port-channel interface manually, I mean by "int Po2"

If so delete the config-line  "channel-group 2 mode on" from both the interfaces & also delete Po2.

Check to see if Po2 is deleted "sh ip int br"

Now put the config "channel-group 2 mode on" under both the interfaces, so this will create the Po2.

Now check to see if both ports joined the Po2.

HTH.

Mark answered if this resolves & also rate if helpful.

Thanks,

Shaz

[johnelliot6]

Thanks!

Honestly cannot remember if the original portchan was created manually or not...

Anyway, just to confirm

Keep existing eth configs, just remove channel group 2, and delete portchan int, and confirm portchan is deleted, then add channel group 2 mode on to both ints, and the new portchan will automagically get the config(ii.e. allowed vlans etc) from the eth interfaces?

Do I need to do anything to the connecting switch config?

Cheers!

[CiscoIsInYou]

Everything is correct except the last one. A new Port-ch will be created but with no configs like any default interface. You have to manually configured parameters for the Po2.

HTH.

Thanks

Shaz

[johnelliot6]

Hi - Just an update on this, the removal of chan group 2 from eth ints, deleting of portchan etc did not work - What did work was setting eth int to default (default interface fastEthernet 0/x) and then re-adding the original eth port config...working now with both eth ints as members of portchan.