Solved: Netflow on 4500

Olivier Jessel · ‎09-15-2009

Hi all,

As far as I've read, netflow on C4500 should be globally configured by entering : ip flow ingress infer-fields.

Ok, but if I enter tis, what exactly the switch will do ?

My goal is to simply monitor the traffic from a port of this switch to the Firewall. (LAN to outside traffic)

But if the CPU o switch goes crazy because it's processing too much traffic, is there any other possibility to do this ?

If someone could light my mind, I'd really appreciate :))

Thanks in advance for your support

Regards,

Olivier

CCIE #44658

yagnesh_tel · ‎09-15-2009

Hello Olivier,

Once you configure netflow on your switch, switch collects traffic statistics about the packets that flow through the switch and stores the statistics in the NetFlow table. You can view these stats on switch itself or you can export this data to Station running Netflow collector software to view in graphical manner. There are other options such as ip accounting(not supported on 4500) and NBAR which you can use to collect traffic stats depeding on they are supported by your platform or not. As you have identified, Netflow process is bit cpu and memory intensive and usually gives around 2-5% extra load on your cpu. So depending on your current usage you should decide whether to use netflow or not.

Also note that Netflow is supported on 4500 platform depending on supervisor and image you are running. Supervisor Engine 6-E and LAN base image do not support Netflow.

For configuration help refer:

http://www.cisco.com/en/US/docs/switches/lan/catalyst4500/12.2/50sg/configuration/guide/nfswitch.html

View solution in original post

yagnesh_tel · ‎09-15-2009

Hello Olivier,

Once you configure netflow on your switch, switch collects traffic statistics about the packets that flow through the switch and stores the statistics in the NetFlow table. You can view these stats on switch itself or you can export this data to Station running Netflow collector software to view in graphical manner. There are other options such as ip accounting(not supported on 4500) and NBAR which you can use to collect traffic stats depeding on they are supported by your platform or not. As you have identified, Netflow process is bit cpu and memory intensive and usually gives around 2-5% extra load on your cpu. So depending on your current usage you should decide whether to use netflow or not.

Also note that Netflow is supported on 4500 platform depending on supervisor and image you are running. Supervisor Engine 6-E and LAN base image do not support Netflow.

For configuration help refer:

http://www.cisco.com/en/US/docs/switches/lan/catalyst4500/12.2/50sg/configuration/guide/nfswitch.html

Olivier Jessel · ‎09-15-2009

Hi yagnesh,

Thanks for your reply. I have 2 Supervisor Engine cards V-10GE, so it seems OK.

CPU is running around 48% of load average, I hope it's OK too :))

I'll enable it and let see what happens :)

Thanks again !!!

Olivier

CCIE #44658