1 files changed, 34 insertions, 1 deletions

diff --git a/docs/userguide/architecture.rst b/docs/userguide/architecture.rst
index 800e82224..3abb67b7d 100755
--- a/docs/userguide/architecture.rst
+++ b/docs/userguide/architecture.rst
@@ -156,7 +156,40 @@ on OPNFV testing dashboard which use MongoDB as backend.
 
 Logical View
 ============
-TBD(Qiliang)
+Yardstick Logical View describes the most important classes, their
+organization, and the most important use-case realizations.
+
+Main classes:
+
+**TaskCommands** - "yardstick task" subcommand handler.
+
+**HeatContext** - Do test yaml file context section model convert to HOT,
+deploy and undeploy Openstack heat stack.
+
+**Runner** - Logic that determines how a test scenario is run and reported.
+
+**TestScenario** - Type/class of measurement for example Ping, Pktgen, (Iperf,
+LmBench, ...)
+
+**Dispatcher** - Choose user defined way to store test results.
+
+TaskCommands is the "yardstick task" subcommand's main entry. It takes yaml
+file (e.g. test.yaml) as input, and uses HeatContext to convert the yaml
+file's context section to HOT. After Openstacik heat stack is deployed by
+HeatContext with the converted HOT, TaskCommands use Runner to run specified
+TestScenario. During first runner initialization, it will create output
+process. The output process use Dispatcher to push test results. The Runner
+will also create a process to execute TestScenario. And there is a
+multiprocessing queue between each runner process and output process, so the
+runner process can push the real-time test results to the storage media.
+TestScenario is commonly connected with VMs by using ssh. It sets up VMs and
+run test measurement scripts through the ssh tunnel. After all TestScenaio
+is finished, TaskCommands will undeploy the heat stack. Then the whole test is
+finished.
+
+.. image:: images/Logical_view.png
+   :width: 800px
+   :alt: Yardstick Logical View
 
 Process View (Test execution flow)
 ==================================