LACP issues between C9300 and C9200

[cherneff]

Hello all,

i have a problems with setting up LACP between 2 x C9300X-48TX in stack and 2x C9200 in stack. On 9300 i have C9300X-NM-8Y.

on 9200 we have

int Te1/1/1 and Te2/1/1

chanell-group 1 mode active

Po1
switchport mode trunk

switcport trunk allowed vlan 2,3,5

on 9300 on other hand we have

int Te1/1/1 and Te2/1/1

chanell-group 1 mode active

int Po1

switchport mode trunk

switcport trunk allowed vlan 2,3,5

also Twe1/1/1 and Twe2/1/1 no sh

So with this config interfaces going in suspended mode .

when i configure trunk between the devices using single physical port there is no issues .

Could you please advice how exactly they should be configured when i see  TenGig and TwentyGig interfaces on C9300X-NM-8Y and where should i look for fixing this issue .

Thank you in advance!

[Leo Laohoo]

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@cherneff wrote:
So with this config interfaces going in suspended mode .

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When a switch strikes down the link, it will leave reason(s) in the logs.  

What does the log say?

[Jens Albrecht]

Hello @cherneff,

I have seen this happen many times, especially if allowed-vlan lists are configured on etherchannels. Don't remember the exact log message but some complaint about vlan lists not matching even though config was exactly same on both sides.

First thing you should try is to just remove the allowed-vlan list on both sides.
Use the command "switchport trunk allowed vlan all" for both port-channel interfaces.
In most cases this was sufficient to bring up the etherchannel successfully. Once the etherchannel is up on both sides, you can then configure the allowed-vlan list again on both port-channels and the etherchannel will remain up.

If removing the allowed-vlan list is not sufficient, then shut down both port-channel interfaces after you removed the allowed-vlan list. Make sure that the physical interfaces on both switches follow the port-channel interface and go into administratively disabled as well. This is important to make sure that any error conditions are properly cleared.
Do a "no shut" on both sides, the etherchannel should come up now successfully and then you can reconfigure the allowed-vlan list on both sides.

I do not know why Cisco switches stumble from time to time if you configure port-channels with allowed-vlan lists.
As a result I use to apply them only after the etherchannel was established successfully.

HTH!

[cherneff · Accepted solution]

Hello,

thank you all for the suggestions. Indeed  the problem was with VLAN mismatch. On 9300 site i miss allowed vlan command on the physical TweGig interfaces, it was only on Po interface. So when i add it, the issues was fixed.

Thank you again for the suggestions!