[c-nsp] Sup720, multicast bothers the CPU

[Phil Mayers]

On 23/03/11 09:16, Peter Rathlev wrote:
> On Wed, 2011-03-23 at 09:04 +0000, Phil Mayers wrote:
>> If you just want to drop all multicast, you could try:
>>
>> int VlanXX
>>    ip multicast boundary MULTICAST-drop
>> ip access-list standard MULTICAST-in
>>    deny 224.0.0.0 15.255.255.255
>
> Would that also discard forwarding of multicast packets L2-wise? Or only
> L3-wise?

Layer 3.

>> There are also mls rate-limiters for this, but I'm not sure off the top
>> of my head which one you want - we have multicast configured so don't
>> need them (the box builds hardware mfib entries, which stops the CPU punts)
>
> That has me interested: What can I configure to make the traffic
> hardware swithed? Is it as simple as an IGMP querier or something like
> that?
>

If you don't have (and don't want) a "real" multicast config, then I'm 
not sure what the minimum config needed is.

It might be as little as:

ip multicast-routing

...globally.