Configure Netflow top talker

[sreeraj.murali]

Hi, Request assistance in configuring and retrieving top LAN Internet users from the Internet Router WAN interface-Cisco 2900 series Router.

Kindly help with the configuration and verification command to retrieve the TOP Talker list. Also, let me know, if this is going to increase the load on the Router.

[Julio E. Moisa]

Hi

Netflow top talkers is usually supported on Cisco routers and robust L3 switches. 

The configuration could be:

conf t

ip flow-top-talkers
top 100   <--- how many lines of top talkers to be displayed, in this case it will show 100 IP addresses.
sort-by bytes   <--- to see by packets or bytes (i recommend bytes)
cache-timeout 10000   <--- Time in miliseconds to be displayed

Match  <---- optional It is used to match specific source and destination. 

interface Gx/x

Ip flow egress

ip flow ingress (optional)

Now to see the top talkers, you can use the following command line:

show ip flow top-talkers

Hope it is useful

:-)

[sreeraj.murali]

Thanks a lot for the expert inputs. Could you please clarify, if this will be cpu(resource consuming) on the router if configured. I have read from Cisco documentation that, NetFlow consumes additional memory and CPU resources. Please guide.

https://www.cisco.com/c/en/us/td/docs/ios-xml/ios/netflow/configuration/15-mt/nf-15-mt-book/cfg-nflow-top-talk.html?referring_site=RE&pos=3&page=https://www.cisco.com/c/en/us/td/docs/ios/12_2/switch/configuration/guide/fswtch_c/xcfnfc.html

Thanks

Sreeraj

[Julio E. Moisa]

Hi

Yes, it uses CPU resources but it depends of your configuration and CPU, you could monitor the top ten 10 users with more bandwidth utilization per short interval time, this files could provide an idea about the utilization:

https://www.cisco.com/c/dam/en/us/solutions/collateral/service-provider/secure-infrastructure/net_implementation_white_paper0900aecd80308a66.pdf

New generation of routers have robust CPU.

Hope it is useful

:-)

[sreeraj.murali]

Thank you, this helps.

[Julio E. Moisa]

Hi

You are welcome

:-)