06-21-2007 01:53 AM - edited 03-05-2019 04:52 PM
A customer of mine is having some issues with NetFlow Data Export. When they enable it on one of their 6500, all have sup720, the CPU gets very busy. The CPU peaks att 90 - 95%, and averages at 75-80%.
If they disable NetFlow Data Export the CPU peaks at 10-15% and averages at 5-7,5%.
The 6504 is running Native IOS, version 12.2.25SXF, and i cant find any caveates in the release notes that would explain this behavoiur.
Could anyone try to help me to find out why this is and try to fix this.
regards JockeW
06-27-2007 05:56 AM
The NetFlow-based features that this section describes apply to the Supervisor Engine 2 and Supervisor Engine 720 only.
NetFlow-based features always need to see the first packet of a flow in software. Once the first packet of the flow reaches software, subsequent packets for the same flow are hardware-switched.
http://cisco.com/en/US/products/hw/switches/ps708/products_tech_note09186a00804916e0.shtml#netflow
06-28-2007 07:17 AM
Hi,
just some idas:
1. on sup720 IOS 12.2 neflow is used only for statistic, it should not be used for traffic switching. be sure that your CEF engine is up and running.
2. Netflow feature on SUP720 is supported in HW, it should not influence the router CPU
3. try to use sampled NEtflow, may be router to much Netflow data to send out of interface and it leads to delays and high CPU load.
if you could post the config part with Netflow configuration on interfaces and global Netflow configuration.
07-16-2007 03:50 AM
Sorry for the long time before my answer. I've been on vacation.
I will check the CEF settings and i will reply, with NDE config, as soon as i can get the configfile from the customer.
Regards JockeW
07-27-2007 03:12 AM
Hi again.
The Netflow configuration is as follows:
mls netflow
mls flow ip interface-full
no mls flow ipv6
ip flow ingress
ip flow-export source Vlan801
ip flow-export version 5
ip flow-export destination 10.101.32.248 2055
mls aging long 64
mls aging normal 32
ip flow-cache timeout active 1
ip flow-cache timeout inactive 15
mls flow ip interface-full
mls nde sender version 7
Regards
Jocke W
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