[c-nsp] multicast bringing big irons to their knees?

[Christian MacNevin]

Thanks all

That's literally all the info I have just now, it's a client network I  
may have to go look at. Just figured I'd toss it out and see if  
anybody had a screamer of a disclaimer on that hardware.

I'll see how much more Ivan find out before I being this world of pain  
down on myself :)

Sent from my iPhone

On Aug 18, 2008, at 9:33 AM, Paul Cosgrove <paul.cosgrove at heanet.ie>  
wrote:

> Hi Christian,
>
> You will need to explain more about the topology, your multicast setup
> and the traffic flows, for instance:
> - Are the foundary switches acting as your RPs?
> - Have you any other commands applied which will cause multicasts to  
> be
> process switched?
> - Do you have high rates of multicast on the network?
> - Are you using any multicast groups which will appear the same as  
> well
> known multicast groups at Layer 2 (e.g. x.0.0.1, x.0.0.2 etc)?
>
> If the Foundary switches are your RPs, the requirement to decapsulate
> register messages could explain why these are affected much more than
> your 6500s, 3750s and netscreens.  'ip pim register-rate-limit 5'
> applied to the cisco designated routers will help if that is the  
> problem
> (not sure about equivalent netscreeen command).
>
> Paul.
>
> Christian MacNevin wrote:
>> Hi
>> I've only got the most superficial of ideas what's going on with this
>> network, but i've been asked if there's any particular reason
>> some Foundry switches would be being brought to their knees every  
>> time
>> mcast is switched on in a network. 65s, 3750s and Netscreens
>> all handle it fine.
>> Given Foundry's marketing, they dobrag that everything's handled in
>> port-based ASICs, but obviously it sounds like this stuff is going
>> to the processor. Maybe it's PIM Sniffing not supported in  
>> hardware, not
>> sure.
>> Anyway, sorry for the amazing vagary here, but it's all I've got  
>> right
>> now. Any thoughts?
>> Cheers
>> Christian_______________________________________________
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>
>
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