Regards, Benoit.
7.4.3 Selection Sequence Statistics Report Interpretation
A Selector MAY be used in multiple Selection Sequences. However,
each use of a Selector must be independent, so each separate logical
instance of a Selector MUST maintain its own individual Selection
State and statistics.
The Selection Sequence Statistics Report Interpretation MUST include
the number of observed packets (Population Size) and the number of
packets selected (Sample Size) by each instance of its Primitive
Selectors.
Within a Selection Sequence composed of several Primitive Selectors,
the number of packets selected for one Selector is equal to the
number of packets observed by the next Selector. The order of the
Selectors in the Selection Sequence Statistics
Report Interpretation MUST match the order of the Selectors in the
Selection Sequence.
For every Selection Sequence, the PSAMP Device MUST periodically
export a Selection Sequence Statistics Report Interpretation using an
Options Template containing the following Information Elements:
Scope: selectionSequenceId
Non-scope: packetsObserved
packetsSelected (first)
...
packetsSelected (last)
The packetsObserved Information Element [PSAMP-INFO] MUST contain the
number of packets seen at the Observation Point, and as a consequence
passed to the first Selector in the Selection Sequence. The
packetsSelected Information Element [PSAMP-INFO]
contains the number of packets selected by a Selector in the
Selection Sequence.
The Attained Selection Fraction for the Selection Sequence is
calculated by dividing the number of observed packets
(packetsObserved Information Element) by the value of selected
packets (packetsSelected Information Element) for the last Selector.
The
Attained Selection Fraction can be calculated for each Selector by
dividing the number of packets selected for that Selector by the
value for the previous Selector.
The statistics for the whole sequence SHOULD be taken at a single
logical point in time, the input value for a Selector MUST equal the
output value of the previous selector.
The Selection Sequence Statistics Report Interpretation MUST be
exported periodically[CSI1] .
Example of Selection Sequence [CSI2] Statistics Report Interpretation:
Selection Sequence 7 (Filter->Sampling):
Observed 100 (observationPointId 1, Interface 5)
Selected 50 (selectorId 5, match IPV4SourceAddress 10.0.0.1)
Selected 6 (selectorId 10, Sampler: Random one out-of ten)
Selection Sequence 9 (Sampling->Filtering):
Observed 100 (observationPointId 1, Interface 5)
Selected 10 (selectorId 10, Sampler: Random one out-of ten)
Selected 3 (selectorId 5, match IPV4SourceAddress 10.0.0.1)
IPFIX Options Template Record:
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Set ID = 3 | Length = 26 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Template ID = 267 | Field Count = 4 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Scope Field Count = 1 |0| selectionSequenceId = 301 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Scope 1 Length = 4 |0| packetsObserved = 318 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Field Length = 4 |0| packetsSelected = 319 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Field Length = 4 |0| packetsSelected = 319 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Field Length = 4 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
The associated IPFIX Data Record:
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Set ID = 267 | Length = 36 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| 7 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| 100 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| 50 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| 6 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| 9 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| 100 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| 10 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| 3 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure K: Example of the Selection Sequence Statistics Report
Interpretation
Notes:
* The Attained Packet Fractions for Selection Sequence 7 are:
Filter 10: 50/100
Sampler 5: 6/50
Number of samples selected: 6
* The Attained Packet Fractions for Selection Sequence 9 are:
Sampler 5: 10/100
Filter 10: 3/10
Number of samples selected: 3
7.3.1 Basic Packet Reports
For each selected packet, the Packet Report MUST contain the
following information:
- The selectionSequenceId Information Element
- Some number of contiguous bytes from the start of the packet,
including the packet header (which includes link layer, network layer
and other encapsulation headers) and some subsequent bytes of the
packet payload. Alternatively, the number of
contiguous bytes may start at the beginning of the payload. The
dataLinkFrameSection, mplsLabelStackSection,
mplsPayloadPacketSection, ipPacketSection, and ipPayloadPacketSection
PSAMP Information Elements are available for this use.
In the Packet Report, the PSAMP device MUST be capable of exporting
the number of observed packets and the number of packets selected by
each instance of its Primitive Selectors (as described by the non
scope Information Element of the Selection
Sequence Statistics Report Interpretation) although it MAY be a
configurable option not to include them. If exported, the Attained
Selection Fraction may be calculated precisely for the Observed
Packet Stream. The Packet Report MAY include only the
final selector packetSelected, to act as an index for that selection
sequence in the Selection Sequence Statistics Report Interpretation,
which also allows the calculation of the Attained Selection Fraction.
The contiguous Information Elements ...