[c-nsp] IP multicast traffic overwhelms switches

[victor]

On Fri, 10 Jul 2009 20:30:19 +0400, Jay Ford <jay-ford at uiowa.edu> wrote:

> I don't think you want “ip mroute-cache”, at least not on 7600/6500  
> boxes.
> My guess is that by configuring that you're disabling the hardware-based
> forwarding & forcing it to software-based forwarding.  Get rid of the “ip
> mroute-cache” & see if things get better on the 7600.
>
ip mroute-cache is the default mode for interfaces. Are you suggesting to  
do "no ip mroute-cache" to disable cef completely.
> Are the 4900 boxes doing L3 or just L2?  I suspect they'd do much better  
> at
> L2 fan-out of multicast than at L3 fan-out.  You're probably hitting a  
> pps or
> packet replication limit before hitting the bps limit.
I agree that this switch will probably perform better doing L2 exchange  
but then there is another problem: C7604 carry QinQ vlans and C4924  
terminates them giving each tunnel's payload out of a deferent  
dot1q-tunnel access port. If I don't do multicast routing I will need to  
carry the same multicast traffic on every configured outer vlan. This will  
eat up all the bandwidth.


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