Netflow on SUP720-3BXL

Andy Bierlair globichen at gmail.com
Sat Mar 14 21:20:20 CDT 2009


yes ip cef, this is enabled:

  IP fast switching is enabled
  IP fast switching on the same interface is disabled
  IP Flow switching is enabled
  IP CEF switching is enabled
  IP Flow switching turbo vector
  IP Flow CEF switching turbo vector

and so on...

-
Andy

On Sun, Mar 15, 2009 at 3:08 AM, Bill Blackford
<BBlackford at nwresd.k12.or.us> wrote:
>
> just a shot in the dark. Do you have 'ip cef' in global config?
>
> -b
> ________________________________________
> From: Andy Bierlair [globichen at gmail.com]
> Sent: Saturday, March 14, 2009 6:55 PM
> To: nanog at nanog.org
> Subject: Netflow on SUP720-3BXL
>
> I’m trying to run netflow on one of our Cisco core routers (SUP720-3BXL),
> but I think I am hitting some limitations because of this:
>
>
>
> %EARL_NETFLOW-SP-4-TCAM_THRLD: Netflow TCAM threshold exceeded, TCAM
> Utilization [99%]
>
>
>
> The setup of netflow looks like this:
>
>
>
>  ip flow-cache entries 524288
>
>  mls aging fast time 5 threshold 32
>
>  mls aging long 300
>
>  mls aging normal 60
>
>  mls netflow usage notify 80 300
>
>  mls flow ip full
>
>  no mls flow ipv6
>
>  mls nde sender version 5
>
>  no mls verify ip checksum
>
>  no mls acl tcam share-global
>
>
>
>  ip flow-export source Loopback0
>
>  ip flow-export version 5 origin-as
>
>  ip flow-export destination <ip> <port>
>
>
>
> Then I have this enabled on all border interfaces/vlans (peering / transit /
> other core routers) that are of interest for my stats:
>
>
>
>  ip route-cache flow
>
>
>
> Some more details about the problem:
>
>
>
> #sh mls netflow table-contention detailed Earl in Module 5 Detailed Netflow
> CAM (TCAM and ICAM) Utilization
> ================================================
>
> TCAM Utilization             :   100%
>
> ICAM Utilization             :   13%
>
> Netflow TCAM count           :   262033
>
> Netflow ICAM count           :   17
>
> Netflow Creation Failures    :   4822220
>
> Netflow CAM aliases          :   1
>
>
>
>
>
> #sh mls netflow table-contention aggregate Earl in Module 5 Aggregate
> Netflow CAM Contention Information
> =============================================
>
> Netflow Creation Failures    :   130003616
>
> Netflow Hash Aliases         :   4
>
>
>
>
>
> I understand that the TCAM is full, but what can I do against it? This is a
> busy core router:
>
>
>
> Aggregated traffic: 7-8 GBIT/s
>
> Packets per Second: 1.0 - 1.2 Million
>
>
>
> I wouldn't mind analyzing only every 10th or 100th flow, which seems to be a
> common practice.
>
>
>
> Any good piece of advice is welcome.
>
>
>
> Thanks!
>
>
>
> -
> Andy




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