Cisco 3750 and Netflow

[ismail.patel]

Hello All,

I am trying to setup netflow collection on a CISCO 3750 running 12.1.9EA1d without much success. Netflow configuration is straight forward i.e.

int fastethernet 1/0/x

ip route-cache flow

is all thats required ( for a simple config )

However when I use "show ip cache flow" I do not see any flows. I have sucessfully implemented netflow on a CISCO 2621 without issues.

I do see some flows appear every couple of hours but not to the level I am expecting.

Having researched this on the web, I believe the problem to be with distributed CEF but there is no way to turn this off globally or on an interface level.

Has anybody sucessfully configured netflow on a CAT 3750? if so, how!!

Many Thanks.

Ismail.

[smif101]

You can turn off cef by issuing the command no ip cef in global configuration mode. Of course I don't believe you are running distrubted CEF because that requires a VIP which is only on the 7000 series routers.

[ismail.patel]

Thank you for the update.

Like yourself i was under the impression that you needed special hardware for dCef. However, the CAT 3750 only supports this mode. See Below:

MHSE12438#sh ip cef detail

IP Distributed CEF with switching (Table Version 10820), flags=0x0

167 routes, 0 reresolve, 0 unresolved (0 old, 0 new), peak 0

167 leaves, 23 nodes, 54080 bytes, 4200 inserts, 4033 invalidations

45 load sharing elements, 15120 bytes, 45 references

universal per-destination load sharing algorithm, id B1A0A3BF

3(0) CEF resets, 4608 revisions of existing leaves

Resolution Timer: Exponential (currently 1s, peak 1s)

6625 in-place/0 aborted modifications

refcounts: 6499 leaf, 6144 node

Unfortunately CEF cannot be disable on the box as it returns error message:

MHSE12438(config)#no ip cef distributed

%Cannot disable CEF on this platform

I have tried "no ip route-cache cef" on the interface but this does not help either.

Ismail.

[pflunkert]

Hi,

ip route-cache is an unsupported command.

http://www.cisco.com/en/US/partner/products/hw/switches/ps5023/products_configuration_guide_chapter09186a00801f6169.html

Regards

Peter