I worked with Brad Reese and some of our internal engineering folks to put this post together on a Free NetFlow Forwarder or NetFlow Duplicator called “The Samplicator”. Read more »
Michael Patterson
A customer called the other day regarding NetFlow collection and interface descriptions not matching the correct interface instance numbers. I’d seen this issue before and knew it was not related to the NetFlow configuration, but rather that the device in question was exporting the wrong interface information in the NetFlow packets.
Michael Patterson addressed this issue in his blog, “Messed Up Interface names in Scrutinizer” in February.
To summarize Michael’s blog, the device in question was including interface instance numbers from enterprise mibs in the NetFlow packets, and most NetFlow Traffic Analyzers get the interface descriptions from the standard MIB-2 ifIndex tables.
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How do you know if the NetFlow collector is saving or even getting all of the NetFlow datagrams that are being sent to it or that it is receiving? It is important to know if any flows are missing.
Why do we care?
This is a great question. We care because a loss of flow exports is usually caused by one of three things:
NetFlow sequence numbers are becoming increasingly important. When building a NetFlow collector it is important that the engine scales while staying accountable. If you look at the NetFlow v9 packet format you will notice something called the package_sequence.
Just the other day, Brad Reese from Network World wrote a nice blog reflecting on the recent announcement of H.P. acquiring 3Com.
With a huge announcement like this, naturally there are a lot of reactions and opinions. This kind of move may impact a lot of people and their current network strategies.
But coming from a NetFlow, sFlow and Netstream vendor perspective, I think this could be good news.
Optimization of the network often starts with removing traffic that doesn’t need to be there. This topic has been a growing concern for several years. Just ask google.com:
Scrutinizer NetFlow & sFlow Analyzer from Plixer International can support NetStream packets, developed by Huawei-3Com Co., Ltd (H3C).
Huawei-3Com Co., Ltd (H3C) began operations as a joint venture between Huawei and 3Com in November 2003. In 2006, they officially went their separate ways, with 3Com buying out Huawei’s share in H3C. H3C, as 3Com’s presence in China, continued to prosper, until the non-compete clause that Huawei agreed to ended.
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