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issue with EthChannel

Hi..

I configured EthChannel to aggregate two Gig interfaces between Cisco 6509 core sw and AIX server (Teaming).

Config on 6509 core as following:

On both interfaces (assume Gi7/7 & Gi7/8)

swichport

switchport access vlan 5

switchport mode access

channel-group 8 mode active

I have checked the server's NIC, it supported LACP aggregatoin type.

output ---> port-channel 8 created but ONLY interface G7/7 is member of this bundle and I found that port-channel 8A created automatically and G7/8 considered as member of this virtual bundle.

I'm trying to figure out the logic behind creation of port-channel 8A !!

any helpful comments !!!

Thx

9 REPLIES

Re: issue with EthChannel

Hi Belal,

I believe you should specify the channel-protocol on the interface level explicitly to be lacp:

channel-protocol lacp

Try this.

Cheers:

Istvan

New Member

Re: issue with EthChannel

Hi Istvan,

I believe once I configured mode active it will select the LACP as the protocol for aggregation and I can confirm that LACP is the running protocol, I issued the command "show interface port-channel 8 eth"

it clearly shows that LACP run.

Re: issue with EthChannel

Istvan,

It is not really necessary to specify the channel-protocol because LACP is already implied in the "active" (or "passive") setting.

In fact, the channel-protocol is not a very useful command because it only serves as a sort of configuration safety lock ... a sort of "belt-and-braces" tautology. It has no direct influence on the mode of the channel.

Kevin Dorrell

Luxembourg

Re: issue with EthChannel

Hi Kevin,

Thank you for the contribution.

I want to share my experience with you:

channel-protocol pagp

channel-group 1 mode on

And the channel did not form.

So if the channel-protocol is specified, then very interestingly, the switch does not accept "on" mode.

(In "on" mode no pagp messages sent.)

I hope someone will use this info somewhere.

Cheers:

Istvan

Re: issue with EthChannel

That's good!

Thank you Edison.

Cheers:

Istvan

Hall of Fame Super Bronze

Re: issue with EthChannel

That's very odd. I don't think is possible to have an interface with a number and a letter.

Can you post the output from typing

show version

show interface brief

and

show ether sum

Thanks

__

Edison.

New Member

Re: issue with EthChannel

Hi Edison,

believe me its possible, but the amazing thing that I found it today working fine and both interfaces shown in port-chahnnel 9 but to convince you that number and a letter is there I copied the logs and below the output:

Apr 7 14:38:46.765 KWT: %LINEPROTO-5-UPDOWN: Line protocol on Interface Port-channel9A, changed state to down

Apr 7 14:38:46.801 KWT: %LINK-3-UPDOWN: Interface GigabitEthernet7/9, changed state to down

Apr 7 14:38:46.769 KWT: %LINEPROTO-SP-5-UPDOWN: Line protocol on Interface GigabitEthernet7/9, changed state to down

Apr 7 14:38:46.769 KWT: %LINEPROTO-SP-5-UPDOWN: Line protocol on Interface GigabitEthernet7/10, changed state to down

Apr 7 14:38:46.813 KWT: %LINK-3-UPDOWN: Interface Port-channel9A, changed state to down

Apr 7 14:38:46.817 KWT: %LINK-3-UPDOWN: Interface GigabitEthernet7/10, changed state to down

Apr 7 14:38:47.001 KWT: %LINK-5-CHANGED: Interface Port-channel9A, changed state to administratively down

finally its Cisco, expect more :)

thx for support,

Re: issue with EthChannel

Strange. Never seen that before. Is it IOS or CatOS?

Sorry ... second thoughts I take that back ... it looks like IOS. Still strange though.

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