Ethercahnnel error %EC-5-CANNOT_BUNDLE2

[Jacob Berger]

we have two 6509 connected in vss config.

one 6509 was shutdown due to power problem and was up after a few minutes.

a 2960s that is connected to both 6509 through 2 port etherchannel connection gave the following error:

Feb 23 19:11:12: %LINEPROTO-5-UPDOWN: Line protocol on Interface GigabitEthernet1/0/27, changed state to down

Feb 23 19:11:14: %LINK-3-UPDOWN: Interface GigabitEthernet1/0/27, changed state to down

Feb 23 19:17:37: %EC-5-CANNOT_BUNDLE2: Gi1/0/27 is not compatible with Gi1/0/28 and will be suspended (trunk mode of Gi1/0/27 is access, Gi1/0/28 is trunk)

Feb 23 19:17:39: %LINK-3-UPDOWN: Interface GigabitEthernet1/0/27, changed state to up

Feb 23 19:17:47: %LINEPROTO-5-UPDOWN: Line protocol on Interface GigabitEthernet1/0/27, changed state to up

when i run "sh etherchannel sum" i get:

1      Po1(SU)         LACP      Gi1/0/27(P) Gi1/0/28(P)

so everything seems to be ok.

does the above  %EC-5-CANNOT_BUNDLE2 error just mean that at the time the interface was down the was a problem with the ethercahnnel (expected....)

or is there a problem with the etherchannel config?

[Jon Marshall]

Jacob

Can you post the config for those gigabit ports ?

Jon

[Jacob Berger]

on 2960s
--------

interface Port-channel1
description ### to VSS port 14
ip dhcp snooping trust

interface GigabitEthernet1/0/27
channel-group 1 mode active
ip dhcp snooping trust

interface GigabitEthernet1/0/28
channel-group 1 mode active
ip dhcp snooping trust

on 6509
-------

interface Port-channel14
description #to comp_room
switchport
spanning-tree guard root

interface GigabitEthernet1/2/14
description to ### comp_room
switchport
channel-group 14 mode active
spanning-tree guard root

interface GigabitEthernet2/2/14
description to ### comp_room
switchport
channel-group 14 mode active
spanning-tree guard root

[Jon Marshall]

Jacob

Are these meant to be trunk links or access port links ie. you haven't configured either the physical interfaces or the port channel as either.

Jon

[Jacob Berger]

trunk

you are right that its not configured on the ports

whats the default ?

and where should it be set , on physical ports or on port channel?

(i checked on other switches and trunk is set on both. is that ok?)

thanks

[prajithtr_2]

HI Jacob,

Can you shut and no shut  the Port channel interface.

Prajith

[Jacob Berger]

i can check that later after working hours

[Jon Marshall · Accepted solution]

Jacob

It is obviously negotitating to a trunk otherwise your network wouldn't work but i think you should set them explicity.

I configured the "switchport mode trunk" and the "switchport trunk encapsulation on both physical and port channel in the past.

Jon

[Jacob Berger]

do you think the above error is because trunk is not set and when the port disconnects the link reverts back to access ?

[Jon Marshall]

Jacob

It doesn't seem to be affecting the actual operation once it has formed the etherchannel but yes, i think this may be why you are seeing that error message.

Jon

[Jacob Berger]

do you do this on all interfaces on all switches taking part in the etherchannel ? or just say on the access switches connecting to the backbone?

[Jon Marshall]

Jacob

Do you mean the configuration ?

All trunks should be set to trunks either dynamically or set to on as should the port channels.

Leaving the ports unconfigured just means the port negotiates to either a trunk or an access port but you should configure it rather than leave it up to the switch.

Jon