Description

 LACP goes down after configuring macsec between a QFX5120 and an EX4600. When macsec is removed, LACP comes UP.

Symptoms

After adding macsec configuration, LACP goes down.


set security macsec connectivity-association <ca_name> cipher-suite gcm-aes-128

set security macsec connectivity-association <ca_name> security-mode static-cak

set security macsec connectivity-association <ca_name> mka transmit-interval 6000

set security macsec connectivity-association <ca_name> pre-shared-key ckn abcd

set security macsec connectivity-association <ca_name> pre-shared-key cak "xxxxxxxxxxxxxxxx"

set security macsec interfaces xe-0/0/A connectivity-association <ca_name>

set security macsec interfaces xe-0/0/B connectivity-association <ca_name>


Solution

Since the configuration is between a QFX5120 and an EX4600, the keyword "include-sci" must be added on the QFX5120.



Refer to Configuring MACsec

 

You must enable SCI tagging on a switch that is enabling MACsec on an Ethernet link connecting to an EX4300 or EX4600 switch.

SCI tags are automatically appended to packets leaving a MACsec-enabled interface on an EX4300 or EX4600 switch, so this option is not available on these switches.

You should only use this option when connecting a switch to an EX4300 or EX4600 switch, or to a host device that requires SCI tagging. SCI tags are eight octets long, so appending an SCI tag to all traffic on the link adds a significant amount of unneeded overhead.



After adding the keyword "include-sci" on the QFX5120, LACP came UP.



This is the configuration on the QFX5120 with the keyword "include-sci".


{master:0}[edit]

user@qfx5120# show security | display set

set security macsec connectivity-association <ca_name> cipher-suite gcm-aes-128

set security macsec connectivity-association <ca_name> security-mode static-cak

set security macsec connectivity-association <ca_name> mka transmit-interval 6000

set security macsec connectivity-association <ca_name> include-sci

set security macsec connectivity-association <ca_name> pre-shared-key ckn abcd

set security macsec connectivity-association <ca_name> pre-shared-key cak "xxxxxxxxxxxxxxxx"

set security macsec interfaces xe-0/0/A connectivity-association <ca_name>

set security macsec interfaces xe-0/0/B connectivity-association <ca_name>

 

{master:0}[edit]

user@qfx5120# run show lacp interfaces

Aggregated interface: aeX

  LACP state:     Role Exp Def Dist Col Syn Aggr Timeout Activity

   xe-0/0/A     Actor  No  No Yes Yes Yes Yes  Fast  Active

   xe-0/0/A    Partner  No  No Yes Yes Yes Yes  Fast  Active

   xe-0/0/B     Actor  No  No Yes Yes Yes Yes  Fast  Active

   xe-0/0/B    Partner  No  No Yes Yes Yes Yes  Fast  Active

  LACP protocol:    Receive State Transmit State     Mux State

   xe-0/0/A         Current Fast periodic Collecting distributing

   xe-0/0/B         Current Fast periodic Collecting distributing

 

 

And this is the configuration on the EX4600.

 


{master:0}[edit]

user@EX4600# show security | display set

set security macsec connectivity-association <ca_name> cipher-suite gcm-aes-128

set security macsec connectivity-association <ca_name> security-mode static-cak

set security macsec connectivity-association <ca_name> mka transmit-interval 6000

set security macsec connectivity-association <ca_name> pre-shared-key ckn abcd

set security macsec connectivity-association <ca_name> pre-shared-key cak "xxxxxxxxxxxxxxxx"

set security macsec interfaces xe-0/0/A connectivity-association <ca_name>

set security macsec interfaces xe-0/0/B connectivity-association <ca_name>


{master:0}[edit]

user@EX4600# run show lacp interfaces

Aggregated interface: aeX

  LACP state:   Role Exp Def Dist Col Syn Aggr Timeout Activity

   xe-0/0/A   Actor  No  No Yes Yes Yes Yes  Fast  Active

   xe-0/0/A  Partner  No  No Yes Yes Yes Yes  Fast  Active

   xe-0/0/B   Actor  No  No Yes Yes Yes Yes  Fast  Active

   xe-0/0/B  Partner  No  No Yes Yes Yes Yes  Fast  Active

  LACP protocol:    Receive State Transmit State     Mux State

   xe-0/0/A         Current Fast periodic Collecting distributing

   xe-0/0/B         Current Fast periodic Collecting distributing



Modification History

2026-05-05 : Article Created