To dig deep into your organization’s network behavior and movement of traffic, you need to better understand NetFlow data in your routers. Enabling NetFlow on your routing and switching devices allows you to collect traffic statistics from that device. When traffic passes through the interfaces of a NetFlow enabled device, relevant information about the IP conversation is captured and stored in the NetFlow cache.

 

Quick Recap – What is NetFlow?

NetFlow is a network protocol developed by Cisco® Systems for collecting IP traffic information. Over time, this protocol has become the universally accepted standard on traffic monitoring. NetFlow answers the questions of who (users), what (applications), and how network bandwidth is being used.

 

What is NetFlow v5?

NetFlow v5, or traditional NetFlow, is the most widely used and supports AS reporting and a few additional fields. The packet format is fixed and always the same, making it easy to decipher for most NetFlow collection and network traffic reporting packages.

 

What is NetFlow v9?

Version 9 is the Flexible NetFlow technology. The distinguishing feature of the NetFlow Version 9 format is that it‘s template-based. Templates provide a flexible flow export with user defined key and non-key fields. It has the ability to monitor a wide range of IP packet information which is absent in traditional NetFlow.

 

The slideshare below will give you more details on How to Configure NetFlow v5 & v9 on Cisco Routers.

 


 

 

Once NetFlow is configured on the routers, the NetFlow packets are sent to the designated server or collector. Having a tool in place that collects all NetFlow packets and presents them in an easy to understand, comprehensive view helps you effectively manage your bandwidth. Efficient network operation lowers costs and drives higher business revenues through better utilization of the network infrastructure.

 

Learn More

Whitepaper – NetFlow Tips and Tricks

Seven Priorities of Network Management by EMA

Geek’s Guide to the NetFlow v9 Datagram

NetFlow Lab – Thwack Community