+
+Methodology: IPSec with Intel QAT HW cards
+------------------------------------------
+
+VPP IPSec performance tests are using DPDK cryptodev device driver in
+combination with HW cryptodev devices - Intel QAT 8950 50G - present in
+LF FD.io physical testbeds. DPDK cryptodev can be used for all IPSec
+data plane functions supported by VPP.
+
+Currently CSIT |release| implements following IPSec test cases:
+
+- AES-GCM, CBC-SHA1 ciphers, in combination with IPv4 routed-forwarding
+ with Intel xl710 NIC.
+- CBC-SHA1 ciphers, in combination with LISP-GPE overlay tunneling for
+ IPv4-over-IPv4 with Intel xl710 NIC.
+
+Methodology: TRex Traffic Generator Usage
+-----------------------------------------
+
+The `TRex traffic generator <https://wiki.fd.io/view/TRex>`_ is used for all
+CSIT performance tests. TRex stateless mode is used to measure NDR and PDR
+throughputs using binary search (NDR and PDR discovery tests) and for quick
+checks of DUT performance against the reference NDRs (NDR check tests) for
+specific configuration.
+
+TRex is installed and run on the TG compute node. The typical procedure is:
+
+- If the TRex is not already installed on TG, it is installed in the
+ suite setup phase - see `TRex intallation`_.
+- TRex configuration is set in its configuration file
+ ::
+
+ /etc/trex_cfg.yaml
+
+- TRex is started in the background mode
+ ::
+
+ $ sh -c 'cd /opt/trex-core-2.25/scripts/ && sudo nohup ./t-rex-64 -i -c 7 --iom 0 > /dev/null 2>&1 &' > /dev/null
+
+- There are traffic streams dynamically prepared for each test. The traffic
+ is sent and the statistics obtained using trex_stl_lib.api.STLClient.
+
+**Measuring packet loss**
+
+- Create an instance of STLClient
+- Connect to the client
+- Add all streams
+- Clear statistics
+- Send the traffic for defined time
+- Get the statistics
+
+If there is a warm-up phase required, the traffic is sent also before test and
+the statistics are ignored.
+
+**Measuring latency**
+
+If measurement of latency is requested, two more packet streams are created (one
+for each direction) with TRex flow_stats parameter set to STLFlowLatencyStats. In
+that case, returned statistics will also include min/avg/max latency values.