broadcast storm control using QOS to stop it to punt the CPU

[deepak george]

Hi,

How do i supress the broadcast in Nexus switches(5672UP's)

Our's is a lab environment and we have a lot of teams generating a lot of broadcast traffic. Broadcast storm control detection will help, however  the traffic hits the CPU and would cause CPU utilisation.

Can i use QOS to ensure that the traffic doesn't punt the CPU?If yes can you share any info

[Reza Sharifi]

Hi,

On the 5600 series, you can configure broadcaset control on Portchannels as well as host ports (FEX ports).

Here is the config guide:

https://www.cisco.com/c/en/us/td/docs/switches/datacenter/nexus5600/sw/layer2/7x/b_5600_Layer2_Config_7x/b_6k_Layer2_Config_7x_chapter_01101.html#task_1072339

HTH

[deepak george]

Thanks Reza,

I am looking for an option to control the broadcast storms punting the CPU like COPP or QOS.

Do you have any suggestions for the same.

Thanks

Deepak

[Reza Sharifi]

Hi,

So, what is the cpu utilization when there is a lot of broadcast traffic? Does it go up significantly?

I think if you stop it at the ingress ports (access ports) than you should not see much of cpu utilization by broadcast traffic.

HTH

[deepak george]

Hi Reza,

Thanks for getting back.

I am looking to configure broadcast storm control on a layer 3 interface on N5672UP.

I know that broadcast storm is a layer 2 feature and might not support on Nexus. Is there a way i can overcome this as this is available on a normal catalyst switch.

Ours is a development enviornment and we have a lot of traffic generated. This is our aggregation layer switch and we have a lot of gateways confgured

[deepak george]

The CPU utilisation would be between 85 to 95%

[paul driver]

Hello

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@deepak george wrote:

Hi Reza,

Thanks for getting back.

I am looking to configure broadcast storm control on a layer 3 interface on N5672UP.

I know that broadcast storm is a layer 2 feature and might not support on Nexus. Is there a way i can overcome this as this is available on a normal catalyst switch.

Ours is a development environment and we have a lot of traffic generated. This is our aggregation layer switch and we have a lot of gateways confgured

---

Broadcast isnt traversed over L3  so as resa suggested negate as close to the source as possible (storm control) and i would say that your cpu usage will decrease IF that's what causing  high cpu process in the first place?

On a side note - you have directed broadcast enabled?

res
Paul

[jkilleda]

broadcast storm control using QOS to stop it to punt the CPU

You can use the traffic storm control feature to prevent disruptions on Layer 2 ports by a broadcast, multicast, or unknown unicast traffic storm