[nsp] 2950 Broadcast Storm

[Stephen J. Wilcox]

Depends whats on the port.. some things have higher broadcast than others, 
theres no right answer to this.

Why dont you graph the broadcast and traffic counters for a few days and see 
what 'normal' looks like and then pick a figure suitably high enough to be 
considered 'abnormal' .. perhaps 5x or 10x normal..?

Steve

On Thu, 11 Mar 2004, Daniel Quiambao wrote:

> 
> 
> Hi there,
> 
> Thanks for all your reply.
> However, is there a formula to calculate the percentage (or threshold) of the
> broadcast storm need to be block.
> 
> Let say, I have a 100Mbps FE Port that has an average of utilisation of 50Mbps.
> When applying a treshold level,
> should I set it to 50%?
> 
> Thanks
> Daniel
> 
> 
> 
> 
> 
> 
> Cristian BICA <bcd at rdsnet.ro> on 03/10/2004 07:16:33 PM
> 
> To:   cisco-nsp at puck.nether.net
> cc:   "'cisco-nsp at puck.nether.net'" <cisco-nsp at puck.nether.net> (bcc: Daniel
>       Quiambao/ENGR/1-Net)
> 
> Subject:  Re: [nsp] 2950 Broadcast Storm
> 
> 
> 
> -----BEGIN PGP SIGNED MESSAGE-----
> Hash: SHA1
> 
> 
> checkout bugid CSCdp30543 before configuring anything
> 
> http://www.cisco.com/cgi-bin/Support/Bugtool/onebug.pl?bugid=CSCdp30543&Submit=Search
> 
> 
> On Wednesday 10 March 2004 12:53, Stork, D.H. (Duncan) wrote:
> > Hi,
> > I suppose you mean the following?
> > Switch(config-if)# storm-control broadcast level [high level] [lower
> > level]
> >
> > [high level]
> > Specifies the upper threshold levels for broadcast traffic. The storm
> > control action occurs when traffic utilization reaches this level.
> >
> > Optional:
> > [lower level]
> > Specifies the falling threshold level. The normal transmission
> > restarts (if the action is filtering) when traffic drops below this
> > level for interfaces that support software-based suppression.
> >
> > Then configure the action to take:
> > Switch(config-if)# storm-control action {shutdown | trap}
> >
> > If you don't set a particular action it will filter out the broadcast
> > traffic and not send out traps.
> > The "shutdown" keyword puts the port in an error-disable state during
> > a storm. If the [lower level] is not set, the port remains in
> > shutdown state until you set it to "no shut"
> > The "trap" keyword sends out an SNMP trap when a storm is detected.
> >
> > Kind regards,
> >
> > Duncan Stork
> >
> >
> >
> > -----Oorspronkelijk bericht-----
> > Van: Daniel Quiambao [mailto:danielq at 1-net.com.sg]
> > Verzonden: woensdag 10 maart 2004 10:31
> > Aan: 'cisco-nsp at puck.nether.net'
> > Onderwerp: [nsp] 2950 Broadcast Storm
> >
> >
> >
> >
> > Hi there,
> >
> > I am trying to limit the broadcast storm on the 2950 switch, but I
> > can't find a
> > recommendation from Cisco.
> > I understand that to limit broadcast storm is depend on the port
> > utilization,
> > any better suggestion?
> >
> > Thanks
> > Daniel
> >
> >
> > ====================
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> - --
> 
> 
> Cristian  Bica  --  Network  Engineer
> Romania Data Systems NOC in Bucharest
> T:+4021 30 10 888  F: +4021 30 10 892
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