[j-nsp] Inline IPFIX sampling rate
plunin at gmail.com
Tue Jul 25 05:30:37 EDT 2017
It's been long time I didn't write here :)
Does anyone know in details how sampling-rate works (if it does) for inline
IPFIX on MX/Trio?
AFAIR sampling rate config hadn't had any meaning for inline IPFIX until
some version of JUNOS. It used to be always 1, no matter what you have in
Question 1: If correct, which version it was when it's changed?
As of the 2nd edition of the MX book, "input rate" must follow the formula
“input_rate=2^n-1”. But it's somewhat poorly explained what it means.
Question 2: Do I correctly understand that the value, configured with
”sampling instance <blah> rate <x>”, must conform to this rule. Here <x> is
not the index of power of two (aka n in the formula above), it is the
actual sampling rate (result of the formula), right?
Question 3. Given that I correctly understand the previous point, what if I
configured something that does not conform to this rule e. g. "rate 100"? I
suspect that it should lead to "rate 1" being programmed in the PFE but
can't find a way to check this out. Anyone knows a uKernel command to
verify what is actually applied at the PFE level? It seems that "show
sample instance summary" just replicates the config values.
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