[c-nsp] Cat4500 High CPU with Multicast Stream

[Peter Rathlev]

On Wed, 2011-07-13 at 16:03 +0100, Antonio Soares wrote:
> It seems I found an explanation:
> 
> http://www.ryanhicks.net/blog/2008/12/cisco-4500-intermittant-high-cpu-utilization---part-2.html
...
> Now my question, is this limitation specific to the 4500's ? Or does
> it mean that we can bring down any catalyst network with a good
> multicast stream ???

I think any Cisco device, maybe any router/switch of any brand, would
always receive 224.0.0.0/24. Otherwise a lot of things wouldn't work
"out of the box", e.g. HSRP, OSPF, PIM et cetera. It's at least also a
limitation of 6500/7600 switches.

The 6500/7600 can't handle multicast traffic in hardware CoPP by the
way. (I don't know about the 4500, but it seems it can.) Software CoPP
is better than nothing, but it's still possible to cause problems from a
regular workstation. ACL filtering as close to the edge as possible is
the only real solution.

-- 
Peter