X-Git-Url: https://gerrit.onap.org/r/gitweb?p=aai%2Fesr-server.git;a=blobdiff_plain;f=docs%2Fplatform%2Farchitecture.rst;h=cb658efc885d7b1358b7a646eb2342d36f2290f6;hp=18d38b04830e5f7df819dd142733ff004e700f0b;hb=62d9cb474f057cb5a5a80fd52e7c497bb7a77dca;hpb=c6513385acc892dbaf1883df9f93b519e7c49207

diff --git a/docs/platform/architecture.rst b/docs/platform/architecture.rst
index 18d38b0..cb658ef 100644
--- a/docs/platform/architecture.rst
+++ b/docs/platform/architecture.rst
@@ -4,4 +4,27 @@
 Architecture
 ------------
 
+ESR contains two components: esr server module and esr gui module
 
+- ESR
+    - ESR server
+    - ESR gui
+
+ONAP-level Architecture
+^^^^^^^^^^^^^^^^^^^^^^^
+
+In ONAP architecture, ESR is a sub-project of A&AI. It provide a single point for users to manage the external system information. It provides a way to register/unregister external system dynamically.
+
+.. image:: images/esr-architecture.PNG
+
+How ESR works
+^^^^^^^^^^^^^^^^^^^^^^^
+
+The user register external system through esr-gui, esr-server will store the external system information to A&AI. And the other components such as VF-C/SDNC/Multi-Cloud then can query the external system information form A&AI. The process of VIM register may be a bit different from the VNFM/EMS/thirdparty SDNC. That because the registered VIM information is some basic information such as region/version/auth-url that things, Multi-Cloud will update the cloud information with more details, such as the volume and tenant details. The VNFM/EMS/thirdparty SDNC will not be updated by VF-C and SDNC.
+
+.. image:: images/vim-register-progress.PNG
+.. image:: images/external-system-register-progress.PNG
+
+The complete workflow is shown below in the form of a sequence diagram.
+
+.. image:: images/external-system-register-sequence-diagram.PNG
\ No newline at end of file