[Catalyst 2950] Broadcast problem with Catalyst 2950 – Storm control with DHCP

[DavidCisco2950]

Hello,

My network is composed by 12 Cisco 2950 in 3 different buildings.

We have about 100 computers always connected, with a maximum of 250 simultaneous computer connected.

We have latency problem, visibly broadcast frame is responsible of this problem.

We use DHCP so we can’t use storm-control broadcast.

Can we use storm-control for all ports except the 67 (BOOTP) and 68, to use a limitation for all non DHCP broadcast?

The aim is to keep only the BOOTP frame in broadcast. We can keep a very few other broadcast frame.

We don’t configure computer, each people configure is computer, so we have to do this in the switch.

Thanks you.

[cadet alain]

Hi,

Can we use storm-control for all ports except the 67 (BOOTP) and 68, to use a limitation for all non DHCP broadcast?

No, Storm control is a layer 2 security feature.

But there is other solution to mitigate broadcasts impact such as VLANs, static arp cache,stop using NETBIOS if possible.

I don't think DHCP is the culprit.

Regards.

Alain.

[DavidCisco2950]

Thanks you.

I don’t think DHCP is the culprit but if we can restrain the number of broadcast, DHCP request will be affect by this restriction. So the idea is to restrain all of broadcast frame except DHCP frame.

We can’t use VLANs because, all computers have to communicate each other. We have multiple Internet access sharing and we use pear to pear software to exchange data. Do you know a solution to continue to see each other in different VLAN, a think like VLAN friend.

Have you more information about ARP cache, on this switch?

Thanks.

David

[cadet alain]

Hi,

To communicate between VLANs you must do intervlan routing with a router( router on a stick) or with a L3 switch( using SVIs).

When I was talking about arp cache it was on the hosts.

Have you done a survey to know your traffic and correlate this latency with some broadcast traffic?

Regards.

Alain.