TWSD-1451: 25G Interface shows no carrier on reboot if it is part of bond (when the cables are loopbacked)

Review Request #1266 — Created Dec. 24, 2025 and discarded

Information
ngurunathan
AVX2
TWSD-1451
Reviewers
stevenku, wli 
When a port with loopbacked cables to another port of the NIC are added to bond, both ports go down momentarily. When the second port is also enslaved before it can come up, it results in both ports staying down. 


We can see this behaviour when the ports are added to bond via webui or in quick succession in cli. Also when AVX is rebooted, the ports are added to bond by the backend process taken from conf file in seconds of each other resulting in this behaviour. 


Added delay while adding interface to bond to ensure the ports have time to come up.
After adding delay, able to consistently see interfaces coming up after reboot without any issue.

/var/log/messages:


Dec 19 09:30:13 AN kernel: bond6: Adding slave enp175s0f0

Dec 19 09:30:13 AN kernel: i40e 0000:af:00.0 enp175s0f0: already using mac address 00:0d:48:9a:a6:ed

Dec 19 09:30:13 AN kernel: i40e 0000:af:00.0 enp175s0f0: NIC Link is Down

Dec 19 09:30:13 AN kernel: IPv6: ADDRCONF(NETDEV_UP): enp175s0f0: link is not ready

Dec 19 09:30:13 AN kernel: bond6: Enslaving enp175s0f0 as a backup interface with a down link

Dec 19 09:30:13 AN kernel: i40e 0000:af:00.1 enp175s0f1: NIC Link is Down

Dec 19 09:30:15 AN kernel: i40e 0000:af:00.1 enp175s0f1: NIC Link is Up 25 Gbps Full Duplex, Flow Control: None

Dec 19 09:30:15 AN kernel: i40e 0000:af:00.0 enp175s0f0: NIC Link is Up 25 Gbps Full Duplex, Flow Control: None

Dec 19 09:30:15 AN kernel: bond6: link status definitely up for interface enp175s0f0, 25000 Mbps full duplex

Dec 19 09:31:13 AN kernel: bond6: Adding slave enp175s0f1

Dec 19 09:31:13 AN kernel: i40e 0000:af:00.1 enp175s0f1: set new mac address 00:0d:48:9a:a6:ed

Dec 19 09:31:13 AN kernel: i40e 0000:af:00.1 enp175s0f1: NIC Link is Down

Dec 19 09:31:13 AN kernel: IPv6: ADDRCONF(NETDEV_UP): enp175s0f1: link is not ready

Dec 19 09:31:13 AN kernel: bond6: Enslaving enp175s0f1 as a backup interface with a down link

Dec 19 09:31:13 AN kernel: i40e 0000:af:00.0 enp175s0f0: NIC Link is Down

Dec 19 09:31:13 AN kernel: bond6: link status definitely down for interface enp175s0f0, disabling it

Dec 19 09:31:15 AN kernel: i40e 0000:af:00.0 enp175s0f0: NIC Link is Up 25 Gbps Full Duplex, Flow Control: None

Dec 19 09:31:15 AN kernel: bond6: link status definitely up for interface enp175s0f0, 25000 Mbps full duplex

Dec 19 09:31:15 AN kernel: i40e 0000:af:00.1 enp175s0f1: NIC Link is Up 25 Gbps Full Duplex, Flow Control: None

Dec 19 09:31:16 AN kernel: bond6: link status definitely up for interface enp175s0f1, 25000 Mbps full duplex
weikai
weikai 
  1. Li Wang should be on holiday.
    
I will assist with the code review.
    

    I cannot reproduce this in the TW lab. 
    
However, if this issue only triggers during the boot process, it should not be modified this way. 
    
This modification would cause the execution of the command "bond interface <bond_name> <port_name>" to become very slow every time it is run.
    

    We should probably implement an appropriate delay near where the configuration is executed during the boot sequence instead.
    1. Thanks for looking into this. QA mentions that creating bond interface with ports where cables are loopbacked is not a valid configuration as we are using lacp for bond interface. I can close the review if this is confirmed.
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    Closing the review as the corresponding bug is closed as loopback config is not a valid config for bond interfaces to be tested and also unable to see the issue in AVX7900, AVX5900.
    
  
    
 
    

 
    
  


    
 
    
 
      

  

 
    


    

 
    

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 Review request changed

    
   


  

  

  






 

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