[QFX] [QFabric] Storm control behavior with threshold level value set on Physical/AE interfaces

Summary:

If we apply storm control on interface all and define a level value, it is expected that whenever the BUM traffic crosses the defined threshold of the physical interface, it gets disabled due to storm control.

But in the case of aggregated Ethernet (AE) interfaces with the above configuration, if any child interfaces cross their threshold value, then the entire AE along with other child interfaces get disabled due to storm control. To fix this issue, storm control should be applied on the relevant AE explicitly, which is described in this article.

Symptoms:

Example

The storm-control configuration is applied on interface all and at level 30.

 storm-control {
        action-shutdown;
        interface all { 
            level 30;
        }
    }

30% of xe-0/0/15 = 3 Gig
30% of xe-1/0/0 = 3 Gig
30% of AE10 = 6 Gig

With the above configuration, the AE10 interface gets disabled on RSNG1 (QFX5100) due to storm control if the BUM traffic on any of the child interfaces crosses 3 Gig.

user@device> show lacp interfaces ae10         
Aggregated interface: ae10
    LACP state:       Role   Exp   Def  Dist  Col  Syn  Aggr  Timeout  Activity
      xe-0/0/15      Actor    No   Yes    No   No   No   Yes     Slow    Active
      xe-0/0/15    Partner    No   Yes    No   No   No   Yes     Fast   Passive
      xe-1/0/0       Actor    No   Yes    No   No   No   Yes     Slow    Active
      xe-1/0/0     Partner    No   Yes    No   No   No   Yes     Fast   Passive
    LACP protocol:        Receive State  Transmit State          Mux State
      xe-0/0/15           Port disabled     No periodic           Detached
      xe-1/0/0            Port disabled     No periodic           Detached

Log messages

2020-03-18T11:37:48.694Z qf1-rsng1 eswd 26768 ESWD_ST_CTL_ERROR_IN_EFFECT - ae10.0: storm control in effect on the port
2020-03-18T11:37:48.694Z qf1-rsng1 eswd 26768 ESWD_ST_CTL_ERROR_DISABLED - ae10.0: storm control disabled port

Solution:

Ideally AE10 should get disabled by storm control if the BUM traffic on AE10 interface crosses 6 Gig, that is 30%.

To achieve this, you need to apply the storm control configuration on AE10 explicitly:

user@device> show configuration ethernet-switching-options storm-control    
action-shutdown;
interface ae10.0 {
    level 30;
}
interface all {
    level 30;
}

With the above configuration, whenever the BUM traffic exceeds 6 Gig on AE10, storm-control will be in effect and will disable the AE10 port along with its child member interfaces as expected. No action will be taken if the BUM traffic crosses 3 Gig on a physical interface.

Only the AE threshold value is considered with the above configuration, that is the total BUM traffic on both the child interfaces.

Modification History:

2021-05-26: Article modified to make it simple and easier to comprehend; excessive content removed

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