3750 broadcast traffic sent to svi blues

Unanswered Question

Good evening,

I am working on an issue where a high amount of broadcast data (15Mbps~) on a vlan on a single 3750 with an SVI is causing the switch's cpu to run at near 100% all day.

The users on this segment need to be routed to the internet etc, but the broadcast does not need to be.

I tried to configure Control Plane Policing on the 3750, it has the “control-plane” command to get into the control plane, but when I go to attach a “service-policy input control-plane-policy”

it fails. the policy-map has a “police 128000 8000 exceed-action drop” etc under the class broadcast. this class-map is matching an acl permit udp any host, etc.

I also thought of using the rate-limit command on the svi, which has helped us with 3640 routers in the past, etc.

Does anyone else have any other ideas? the broadcast HAS to work as fast as possible between the physical ports in that vlan, but it should hit the svi at minimal levels for testing, etc.



I have this problem too.
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Edison Ortiz Fri, 06/06/2008 - 07:09

Hi Joe,

I'm sorry but CoPP is not supported in the 3560/3750 switches.

As soon as the broadcast enters the switch, it's processed by the CPU so you need to control it at the switchport. My suggestion is using storm-control broadcast per switchport but this will affect their broadcast speed which is something you don't want.



Chad Peterson Fri, 06/06/2008 - 14:35

Hi Joe,

As Edison said, there isn't much here you can do.

If you can, have this application use multicast instead.


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