Siva,
Yes, I understand that flow switching only gathers flow data with CEF
enabled.
I have the full Internet routing table there and that dCEF keeps a separate
FIB in the VIP plus the ip flow cache in its memory. And that the CEF white
paper on the Cisco site recommends a minimum of 32MB memory per VIP line
card in distributed mode.
Does that mean I can configure dCEF on all VIP (VIP2-50 128 MB) interfaces
(HSSI, Serial T3 and FE) with no worries?
perhaps I can see also a reduction in RSP CPU utilization and higher
throughput as I plan to install
newly-purchsed VIPs.
thanks for your help.
tito
> ----------
> From: Siva Valliappan[SMTP:svalliap@cisco.com]
> Sent: Monday, May 28, 2001 2:56 PM
> To: BasaAA@etpi.com.ph
> Cc: cisco-nsp@puck.nether.net
> Subject: Re: [nsp] [nsp] VIP if-con and IOS switching (was:
> Monitoring DoS attacks w
>
> one caution when checking VIP CPU. it is normal for the VIP cpu
> to be at 99% if the VIP is doing receive side buffering. receive
> side buffering is enabled if you are running DCEF. if you see a
> VIP cpu at 99%, please check if receive side buffering is in
> effect via
>
> show controller vip <slot> acc
>
> from the RSP or
>
> show vip acc
>
> from the vip console.
>
> with respect to the second part of your question -
> when you enable netflow on a router that is doing CEF switching, flow
> only does accounting. it does not switch packets. when netflow
> is enabled with DCEF, the VIP does the accounting and passes up
> aggregated flows to the RSP. netflow needs memory to keep track of
> the flows running through the router, so your memory requirements
> when running netflow + cef will be higher then just running netflow.
>
> RSP based DFS only co-exists with DCEF in 11.1()CC. in 12.0 and later
> code, distributed fast-switching, and the optimized cache based switching
> schemes such as (optimum and flow (for switching purposes) were removed.
> the only switching scheme other CEF is plain fast-switching for RSP
> based platforms.
>
> regards
> .siva
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