about sFlow instance

Hi,

I have some question about sFlow instance in sFlow version 5.
I understood that the Data Source can have one or more sFlow instances
that have their own Sampling Rate in sFlow version 5.
But,the sFlow version 5 datagram doesn't contain the field of sFlow
instance.I wonder that the sFlow Agent can't send the sampling rate of
sFlow instance.

For example,there are two sFlow instances in some Data source.Their
Sampling Rate was different and these sFlow instances operate by parallel.
I think that the Flow sample that is sampled by one instance should be
distinguished in sFlow datagram.

In page 10 of the sFlow version 5 document,it is described as a example
that two sFlow instance operate by cascade(sub-sampling).
I wonder that sFlow instances can't operate by parallel.

I want to know in detail about sFlow instance.
Any help will be appreciated.

Regards,

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KOBAYASHI ATSUSHI <akoba@nttv6.net>
NTT Information Sharing Platform Lab.