Comments on: NetFlow version 9: egress vs. ingress

By: NetFlow v9 vs. NetFlow v5: What are the differences? - NetFlow & sFlow Network Monitoring - Systrax Blog

Thu, 18 Jun 2009 19:42:50 +0000

[...] flow, which is something that NetFlow v5 can’t do. You need to read this blog on “NetFlow version 9: Egress Vs. Ingress” to understand the value of Egress flows. What I want to stress in this blog is that [...]

By: Mike Patterson

Mike Patterson — Mon, 08 Jun 2009 01:06:45 +0000

Hello Venkatesh,

Cacti and MRTG use SNMP to query the ifInOctets and ifOutOctets of a device to display in and out traffic. I don’t think they use NetFlow at all. The database of these tools is not practical for NetFlow storage. Storage and aggregation are paramount issues to consider for NetFlow analysis and reporting. Here is how we do it:
http://www.plixer.com/blog/scrutinizer/unprecedented-netflow-and-sflow-archiving/

I hope this helps.

Mike

By: venkatesh

venkatesh — Sat, 06 Jun 2009 18:51:45 +0000

Hello,
Some of your posts are awesome, and I really enjoy reading them. I have a very basic question regarding ingress and egress neflow data. How does CACTI or MRTG plot the interface in and out using the netflow v5 only. May be you would have explained this earlier but it would be great if you could explain in more detail if possible with an example.

Thanks,
Venkatesh

By: ip route-cache flow or ip flow ingress… Which do I use? - NetFlow & sFlow Network Monitoring - Systrax Blog

Thu, 04 Jun 2009 15:13:46 +0000

[...] **NOTE** With NetFlow v5, we only had the option to monitor inbound statistics using the ip flow ingress command. However, with the release of NetFlow v9, we now have the option to monitor traffic leaving each interface via ip flow egress. Check out this blog which tackles the question: Which one is better to use? Ingress or Egress? [...]