1 files changed, 26 insertions, 15 deletions
diff --git a/docs/report/vpp_functional_tests_virl/overview.rst b/docs/report/vpp_functional_tests_virl/overview.rst
index cf7a5d2e34..16c7ef7ba0 100644
--- a/docs/report/vpp_functional_tests_virl/overview.rst
+++ b/docs/report/vpp_functional_tests_virl/overview.rst
@@ -1,16 +1,18 @@
 Overview
 ========
 
-VPP Functional Test Topologies in VIRL
---------------------------------------
+Tested Topologies VIRL
+----------------------
 
 CSIT VPP functional tests are executed on virtualized topologies created using
 Virtual Internet Routing Lab (VIRL) simulation platform contributed by Cisco.
 VIRL runs on physical baremetal servers hosted by LF FD.io project.  Majority
 of the tests are executed in the three node logical test topology - Traffic
 Generator (TG) node and two Systems Under Test (SUT) nodes connected in a
-loop. Some tests use two node logical test topology - TG node and SUT node.
-Both logical test topologies are shown in the figures below:::
+loop. Some tests use two node logical test topology - TG node and SUT1 node.
+Both logical test topologies are shown in the figures below.
+
+::
 
     +------------------------+           +------------------------+
     |                        |           |                        |
@@ -48,18 +50,27 @@ Both logical test topologies are shown in the figures below:::
           +------------------>           <------------------+
                              +-----------+
 
-Virtual testbeds are created dynamically whenever a verification job is
-started triggered by the patch submission to gerrit and destroyed upon
-completion of all functional tests. During test execution, all nodes are
-reachable thru the MGMT network connected to every node via dedicated NICs and
-links (not shown above for clarity). Each node is a Virtual Machine and each
-connection that is drawn on the diagram is available for use in any test case.
+SUT1 and SUT2 are two VMs (Ubuntu or Centos, depending on the test suite), TG
+is a Traffic Generator (TG, another Ubuntu VM). SUTs run VPP SW application in
+Linux user-mode as a Device Under Test (DUT) within the VM. TG runs Scapy SW
+application as a packet Traffic Generator. Logical connectivity between SUTs
+and to TG is provided using virtual NICs using VMs' virtio driver.
+
+Virtual testbeds are created on-demand whenever a verification job is started
+(e.g. triggered by the gerrit patch submission) and destroyed upon completion
+of all functional tests. Each node is a Virtual Machine and each connection
+that is drawn on the diagram is available for use in any test case. During the
+test execution, all nodes are reachable thru the Management network connected
+to every node via dedicated virtual NICs and virtual links (not shown above
+for clarity).
+
+For the test cases that require DUT (VPP) to communicate with VM over the
+vhost-user interfaces, a nested VM is created on SUT1 and/or SUT2 for the
+duration of these particular test cases only. DUT (VPP) test topology with VM
+is shown in the figure below including the applicable packet flow thru the VM
+(marked in the figure with ``***``).
 
-For test cases that require DUT (VPP) to communicate with VM over vhost-user
-interfaces, a nested VM is created on SUT1 and/or SUT2 for the duration of
-that particular test case only. DUT (VPP) test topology with VM is shown in
-the figure below including the applicable packet flow thru the VM (marked with
-``*``).::
+::
 
     +------------------------+           +------------------------+
     |      +----------+      |           |      +----------+      |