Hello vinoth,

this command configure the export of flow based statistical based data with Netflow feature.

The data are collected on the network device and exported to a Collector workstation.

Netflow can be very useful for monitoring network, to know what traffic is going over the links for planning and for security also.

flow definition includes source IP destination IP protocol, UDP|TCP port, size and sp on.

see

http://www.cisco.com/en/US/docs/ios/netflow/configuration/guide/12_4/nf_12_4_book.html

Hope to help

Giuseppe