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New Member

2924XL storm/flood control

I am just digging into the functionality of cisco 2924XL switches, so please be tolerant if I am either questioning what is obvious or way off base.

We are a Wireless ISP providing services to Small to Medium Businesses. I have a location where we provide Internet Access to an Executive Office Suites company that rents to a number of individual offices. The offices are all on a flat network connected with Cisco 2924 switches.

Obviously if one person gets a worm or a virus, the network floods with traffic, and everyone suffers.

I was looking at utilizing the function for storm control. Cisco 2924 default PPS settings are Rising/Falling

- Broadcast Storm: 500/250

- Unicast Storm: 5000/2500

- Multicast Storm: 2500/1250

I am assuming that the default values are set for a 100M network which in our case won't work because the Wireless Link is 3M/1.5M to the building. By the time the thresholds are reached the network is flooded with more than 1.5M of traffic.

So, I have a couple of questions:

1. Is there a general rule of thumb for calculating the values for the pps at it relates to BW?

Broadcast PPS

Unicast PPS

Multicast PPS

2. Is the switch port only looking at traffic coming from the user, or is it looking at the Full duplex traffic? I assume it's only looking at traffic coming from the user, not full duplex.

Are there other considerations?

Thanks in advance

Jerry Richardson

airCloud Communications

New Member

Re: 2924XL storm/flood control

Thank you for the links. I had already read that information. Unfortunately the information is too general to answer my question.

What I am looking for specifically is how to determine the values for the pps in my environment without having to do too much experimentation as these are business customers and having the connections go up and down while I figure out out to configure the right pps values is not going to fly.

I would welcome any suggestions as it specifically relates to my question.

Thanks again