[c-nsp] Cat4500 High CPU with Multicast Stream

[Antonio Soares]

What is the address range used by ghost ? I've heard that ghost can kill a
network. But if it not using the 224.0.0.0/24 range and you have at least
"ip igmp snooping" on every switch, I don't see how this could affect the
network.

Regards,

Antonio Soares, CCIE #18473 (R&S/SP)
amsoares at netcabo.pt
http://www.ccie18473.net


-----Original Message-----
From: cisco-nsp-bounces at puck.nether.net
[mailto:cisco-nsp-bounces at puck.nether.net] On Behalf Of Christina Klam
Sent: quarta-feira, 13 de Julho de 2011 15:11
To: cisco-nsp at puck.nether.net
Subject: Re: [c-nsp] Cat4500 High CPU with Multicast Stream

I have the same CPU problem but on a 3750.  How would I add a similar
rate-limit for our ghost traffic?  That command does not work on
12.2(52)SE.

Thank you,
Christina          
>             Message: 9
> Date: Wed, 13 Jul 2011 13:59:28 +0100
> From: Alexander Clouter <alex at digriz.org.uk>
> To: cisco-nsp at puck.nether.net
> Subject: Re: [c-nsp] Cat4500 High CPU with Multicast Stream
> Message-ID: <geh0f8-ujm.ln1 at chipmunk.wormnet.eu>
> 
> Antonio Soares <amsoares at netcabo.pt> wrote:
>> 
>> I have a customer with a few 3560/3750's and one 4500/SUP5 acting as the
>> core switch.
>> 
>> For some reason, when a user start one multicast stream, the 4500 suffers
>> high cpu utilization and the network is affected. Only the 4500 suffers
of
>> this problem, the 3560/3750's don't have any complaints.
>> 
>> I see that the 4500 is a CEF based platform and I know that IP Multicast
is
>> not supported in the CEF path. So I was expecting to have this traffic
>> switched in hardware or fast-switched. But a packet capture shows me that
>> the traffic goes to the cpu. I used this debug and output to confirm
this:
>> 
>> debug platform packet all receive buffer
>> 
>> show platform cpu packet buffered
>> 
>> The processes that eat most of the cpu are "Cat4k Mgmt LoPri" and "Cat4k
>> Mgmt HiPri". We thought this could be a bug and we upgraded the 4500 to
the
>> latest release but the problem is exactly the same. The multicast stream
is
>> processed by the cpu.
>> 
>> Anyone has seen this before ? Is this normal behavior of the 4500 ?
>> 
>> Usually the multicast streams are destined to 224.x.x.x. The end users do
>> not respect the 239 rule.
>> 
>> 
> Sounds like the following might help:
> 
>
http://www.gossamer-threads.com/lists/cisco/nsp/128799?do=post_view_threaded
> 
> It's the following lines you might need:
> ----
> mls rate-limit multicast ipv4 non-rpf 100 10
> mls rate-limit multicast ipv4 partial 250 100
> ----
> 
> Or something similar to them.
> 
> Cheers
> 
> -- 
> Alexander Clouter
> .sigmonster says: I'm not tense, just terribly, terribly alert!
> 






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