[NFVBENCH-59] Add Unit Testing of the NDR/PDR convergence algorithm using the dummy...

[nfvbench.git] / docs / development / design / ndrpdr.rst

diff --git a/docs/development/design/ndrpdr.rst b/docs/development/design/ndrpdr.rst
index 4f611a0..5361174 100644 (file)
--- a/docs/development/design/ndrpdr.rst
+++ b/docs/development/design/ndrpdr.rst
@@ -28,7 +28,17 @@ The default value of 0.1 indicates for example that the measured NDR and PDR are
 actual NDR/PDR (e.g. 0.1% of 10Gbps is 10Mbps). It also determines how small the search range must be in the binary search.
 
 The recursion narrows down the range by half and stops when:
+
 - the range is smaller than the configured load_epsilon value
 - or when the search hits 100% or 0% of line rate
 
+One particularity of using a software traffic generator is that the requested Tx rate may not always be met due to
+resource limitations (e.g. CPU is not fast enough to generate a very high load). The algorithm should take this into
+consideration:
+
+- always monitor the actual Tx rate achieved
+- actual Tx rate is always <= requested Tx rate
+- the measured drop rate should always be relative to the actual Tx rate
+- if the actual Tx rate is < requested Tx rate and the measured drop rate is already within threshold (<NDR/PDR threshold) then the binary search must stop with proper warning
+