Add sampling rate support using PacketSpace and PacketInterval

[alopintsev]

Hello,

I'm encountering an issue with sampling rate detection from Nokia devices.

From analyzing the ipfix traffic dump, I can see that these devices represent the sampling rate using two separate fields: PacketSpace and PacketInterval. The effective sampling rate is the sum of these two values.

Currently, goflow2 does not support this method of calculating the sampling rate.

Best regards,
Alex

[lspgn]

Hello,
Thank you for the suggestion
Could you share a packet capture?

[alopintsev]

Hello! The file is a PCAP compressed in ZIP format. GitHub doesn't support attaching such files directly.
nokia-sampling-rate.pcap.zip

[pchaseh]

I've also run into this problem, in my scenario I'm getting flows from a sampler that's sending samplingPacketInterval=1 samplingPacketSpace=999 to indicate a sample rate of 1000. goflow2 is reading samplingPacketInterval but not samplingPacketSpace which causes flows to go out as having SamplingRate set to 1.