LACP What is the interface color when a specific port is down?

[KyungjunCHOE]

Dear Team,

LACP is set as shown below.

AE group: ae2
Members:          Bndl Rx state       Mux state  Sel state
  ethernet1/13    yes  Current        Tx_Rx      Selected
  ethernet1/14    yes  Current        Tx_Rx      Selected
  ethernet1/15    no   Defaulted      Detached   Unselected(Peer not detected)
  ethernet1/16    yes  Current        Tx_Rx      Selected

ethernet 1/15 is in 'Defaulted' status.

If so, I think the interface icon should be displayed in red or yellow.

But it is displayed in green as shown below.

Is this normal?

[PavelK]

Hello @KyungjunCHOE

thanks for posting.

I believe that interface state has a different meaning than "Mux state" in LACP. Interface state indicates whether an interface's physical state is up (green), down (red), or in an unknown state (gray) which is default out of box status. The "MUX state" in ""show lacp aggregate-ethernet ae1" output indicates a state machine in LACP. I could not find explanation in documentation, however looking into LACP logs from different posts, it looks like that if an interface can't join LACP bundle it cycles from ATTACHED=>DETACHED to CURRENT=>EXPIRED to EXPIRED=>DEFAULTED.

There is not enough information / logs in your post to narrow down a root cause for failure, however it looks like that there was no response (Rx received) from remote peer. Could you look into logs: less mp-log l2ctrld.log to see more details.  

Kind Regards

Pavel

[KyungjunCHOE]

@PavelK thank you for your reply

Yes, that's right. There is no response from the peer.

What I'm curious about is that if there is an error in one port in the AE group, the color of the AE port is yellow (as specified in the guide document). But in reality, I don't understand why 1/15 is displayed in green, for example.

In other LABs, ports with physical problems are displayed in red.

I'm curious that sometimes it's red and sometimes it's green, and I'd like to know which is normal behavior.

[PavelK · Accepted solution]

Hello @KyungjunCHOE

thank you for reply. I would say this is expected. 

If interface 1/15 had physical connection issue / disconnected cable, then color should have been red, however in your case it looks like that the interface 1/15 is up, but has not received LACP response to join AE bundle. LACP is Layer 2 protocol.

If you have physically disconnected the cable and the interface is still showing green, then for this behavior I do not have explanation. 

Kind Regards

Pavel