[c-nsp] Brief CPU spikes on 6500 Sup 720

[ariemer at amnet.net.au]

Guys,

Can ASIC oversubscription cause the switch to unicast out all ports for that ASIC?

I am still seeing some unicast traffic hitting ports where it shouldn't be.

Cheers,

Aaron.


On Thu 15/07/10 12:27 AM , Benjamin Lovell <belovell at cisco.com> wrote:
> Depending on the number of connected IP addresses this can be an issue.
> This is why in most cases it will be better to bring up the MAC table
> timers as opposed to bring down the ARP timers.
> 
> -Ben
> 
> On Jul 14, 2010, at 11:16 AM, Jon Lewis wrote:
> 
> > On Wed, 14 Jul 2010, Phil Mayers wrote:
> > 
> >>> mac-address-table aging-time 14400
> >>> http://www.ciscopress.com/articles/article.asp?p=336872 [1]
> >> 
> >> Or of course drop the ARP timeout:
> >> 
> >> int VlanX
> >> arp timeout 290
> > 
> > I haven't tracked down the exact issue, but we've seen issues when
> using too short an arp timeout on a 6500 vlan interface. Sometimes
> customers will ask for really short arp timeouts to cope with failover
> systems that change an IPs MAC address.
> > 
> > The vlan in question had an arp timeout of 60s and had a couple of KVM
> servers with 100 or so virtual machines. Especially when a large number of
> VMs started up, we'd see periods of packet loss. My assumption is that the
> sup720-3bxl can only handle so much arp activity on a vlan. There was
> nothing in the config to artificially limit arp traffic.
> > 
> > ----------------------------------------------------------------------
> > Jon Lewis | I route
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