Real world sflow vs netflow?

Simon Leinen simon.leinen at
Tue Jul 17 15:32:45 UTC 2012

James Braunegg writes:
> In the end I did real life testing comparing each platform

Great, thanks for sharing your results!

(It would be nice if you could tell us a little bit about the
configuration, i.e. what kind of sampling you used.)

> That being said both netflow and sflow both under read by about 3%
> when compared to snmp port counters, which we put to the conclusion
> was broadcast traffic etc which the routers didn't see / flow.

That's one reason, but another reason would be that at least in Netflow
(but sFlow may be similar depending on how you use it), the reported
byte counts only include the sizes of the "L3" packets, i.e. starting at
the IP header, while the SNMP interface counters (ifInOctets etc.)
include L2 overhead such as Ethernet frame headers and such.

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