+Nested-VM Service Switching
+~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+Nested-VM (Virtual Machine) service switching topology test cases
+require VPP DUT to communicate with nested-VM(s) over vhost-user virtual
+interfaces. Nested-VM(s) is(are) created on SUT1 and/or SUT2 for the
+duration of these particular test cases only. Virtual test topology with
+nested-VM(s) is shown in the figure below.
+
+.. only:: latex
+
+ .. raw:: latex
+
+ \begin{figure}[H]
+ \centering
+ \graphicspath{{../_tmp/src/vpp_functional_tests/}}
+ \includegraphics[width=0.90\textwidth]{virtual-3n-vm-vhost}
+ \label{fig:virtual-3n-vm-vhost}
+ \end{figure}
+
+.. only:: html
+
+ .. figure:: ../vpp_functional_tests/virtual-3n-vm-vhost.svg
+ :alt: virtual-3n-vm-vhost
+ :align: center
+
+Functional Tests Coverage
+-------------------------
+
+|csit-release| includes following VPP functionality tested in virtual VM
+environment:
+
++-----------------------+----------------------------------------------+
+| Functionality | Description |
++=======================+==============================================+
+| ACL | Ingress Access Control List security for L2 |
+| | Bridge-Domain MAC switching, IPv4 routing, |
+| | IPv6 routing. |
++-----------------------+----------------------------------------------+
+| COP | COP address white-list and black-list |
+| | filtering for IPv4 and IPv6 routing. |
++-----------------------+----------------------------------------------+
+| DHCP | Dynamic Host Control Protocol Client and |
+| | Proxy for IPv4 and IPv6 routing. |
++-----------------------+----------------------------------------------+
+| GRE | Generic Routing Encapsulation Overlay |
+| | Tunnels for IPv4. |
++-----------------------+----------------------------------------------+
+| IPSec | IPSec tunnel and transport modes. |
++-----------------------+----------------------------------------------+
+| IPv4 | IPv4 routing, RPF, ARP, Proxy ARP, ICMPv4. |
++-----------------------+----------------------------------------------+
+| IPv6 | IPv6 routing, NS/ND, RA, ICMPv6. |
++-----------------------+----------------------------------------------+
+| L2BD | L2 Bridge-Domain switching for untagged |
+| | Ethernet, dot1q and dot1ad tagged. |
++-----------------------+----------------------------------------------+
+| L2XC | L2 Cross-Connect switching for untagged |
+| | Ethernet, dot1q and dot1ad tagged. |
++-----------------------+----------------------------------------------+
+| LISP | Locator/ID Separation Protocol overlay |
+| | tunnels and locator/id mapping control. |
++-----------------------+----------------------------------------------+
+| QoS Policer Metering | Ingress packet rate metering and marking for |
+| | IPv4, IPv6. |
++-----------------------+----------------------------------------------+
+| Softwire Tunnels | IPv4-in-IPv6 softwire tunnels. |
++-----------------------+----------------------------------------------+
+| Tap Interface | Baseline Linux tap interface tests. |
++-----------------------+----------------------------------------------+
+| IPFIX and SPAN | Telemetry IPFIX netflow statistics and SPAN |
+| | port mirroring. |
++-----------------------+----------------------------------------------+
+| uRPF Source Security | Unicast Reverse Path Forwarding security for |
+| | IPv4 and IPv6 routing. |
++-----------------------+----------------------------------------------+
+| VLAN Tag Translation | L2 VLAN tag translation 2to2, 2to1, 1to2, |
+| | 1to1. |
++-----------------------+----------------------------------------------+
+| VRF Routing | Multi-context VRF IPVPN routing for IPv4 and |
+| | IPv6. |
++-----------------------+----------------------------------------------+
+| VXLAN | VXLAN overlay tunneling for L2-over-IPv4 and |
+| | -over-IPv6. |
++-----------------------+----------------------------------------------+
+
+Functional Tests Naming
+-----------------------