From 84a45f22bba2e2e114184da39e2ee5bcf1c3ca29 Mon Sep 17 00:00:00 2001
From: Dragos Ciprian Nedelcu <Dragos.Ciprian.Nedelcu@enea.com>
Date: Mon, 11 Oct 2021 15:50:05 +0200
Subject: Redundant management communication documentation

Change-Id: I45eb901995c7344785b40df1f6b013a9bf36b486
Signed-off-by: Dragos Ciprian Nedelcu <Dragos.Ciprian.Nedelcu@enea.com>
---
 .../doc/installation_guide.xml                     | 50 ++++++++++++++++++++--
 .../doc/main_changes.xml                           | 14 +++++-
 2 files changed, 60 insertions(+), 4 deletions(-)

diff --git a/doc/book-enea-edge-getting-started/doc/installation_guide.xml b/doc/book-enea-edge-getting-started/doc/installation_guide.xml
index da62568..42d1800 100644
--- a/doc/book-enea-edge-getting-started/doc/installation_guide.xml
+++ b/doc/book-enea-edge-getting-started/doc/installation_guide.xml
@@ -948,11 +948,29 @@ of=/dev/sdb bs=4M conv=fsync</programlisting>
 
           <itemizedlist>
             <listitem>
-              <para>Select a WAN interface to use as the management network
+              <para>Select a WAN interface to use as the primary management network
               interface. This interface is used by the Enea Edge Management
               application to communicate with the uCPE device.</para>
             </listitem>
 
+            <listitem>
+              <para>Select a WAN interface to use as the secondary management network
+              interface. This interface acts as a backup for the primary interface
+              and is used by the Enea Edge Management application to communicate with
+              the uCPE device if the communication through the primary management
+              interface fails. This configuration is optional (i.e. it can be left
+              empty). This interface is used only if Device Call Home communication
+              is enabled. For more details concerning Device Call Home, please
+              see <olink
+              targetdoc="book_enea_edge_getting_started"
+              targetptr="device_callhome_nat">Device Call Home Connection for
+              Deployment behind NAT in the <xi:include
+              href="../../s_docbuild/olinkdb/pardoc-names.xml"
+              xmlns:xi="http://www.w3.org/2001/XInclude"
+              xpointer="element(book_enea_edge_getting_started/1)" /></olink> 
+              Manual.</para>
+            </listitem>
+
             <listitem>
               <para>Plug in additional WAN interfaces (if applicable) and
               provide their Layer 3 configuration. An interface can be
@@ -1197,12 +1215,38 @@ of=/dev/sdb bs=4M conv=fsync</programlisting>
     <title>uCPE Device Monitorization and Control</title>
 
     <para>Once the uCPE device is connected to the Enea Edge Management
-    application, it is ready for central management. Two important functions
+    application, it is ready for central management. Redundant management
+    communication support is present on the uCPE device. Two important functions
     available in the Enea Edge Management GUI are alarm checking and resource
     allocation. Additionally, the device can be rebooted, the factory settings
     can be restored or simply the Enea Edge Management Agent service can be
     restarted.</para>
 
+    <section id="redundant_mgmt_com">
+      <title>Redundant Management Communication</title>
+
+      <para>Redundant management communication support minimizes the risk of
+            losing management connection by allowing the configuration of two
+            interfaces (preferably from two different ISPs) as management
+            interfaces.</para>
+
+      <para>During installation of Enea Edge Runtime on the device using the
+            Web-installer application, the user can optionally configure a
+            secondary management interface. The secondary management interface
+            is used only if the Device Call Home option is enabled when adding
+            the device in the Enea Edge Management application.</para>
+
+      <para>The secondary interface acts as a backup for the primary interface.
+            Connection to the Enea Edge Management application is continuously 
+        monitored. If an issue is detected with the connection through the primary 
+        interface then the device will (try to) automatically connect using the 
+        secondary interface (<literal>fail-over</literal> operation). Once the 
+        issue has been resolved (i.e. the Enea Edge Management application is 
+        again reachable using the primary interface) the connection will 
+        automatically switch to using the primary interface 
+        (<literal>fail-back</literal> operation).</para>
+    </section>
+
     <section id="check_alarms">
       <title>Checking Alarms</title>
 
@@ -1300,4 +1344,4 @@ of=/dev/sdb bs=4M conv=fsync</programlisting>
       </note>
     </section>
   </section>
-</chapter>
\ No newline at end of file
+</chapter>
diff --git a/doc/book-enea-edge-release-info/doc/main_changes.xml b/doc/book-enea-edge-release-info/doc/main_changes.xml
index 629a892..c84dde7 100644
--- a/doc/book-enea-edge-release-info/doc/main_changes.xml
+++ b/doc/book-enea-edge-release-info/doc/main_changes.xml
@@ -58,6 +58,18 @@
         xpointer="element(book_enea_edge_getting_started/1)" /></olink>
         Manual.</para>
       </listitem>
+
+      <listitem>
+        <para><remark>CPDX-3562</remark>Added redundant management communication
+        support in Enea Edge Runtime. For more details please see <olink
+        targetdoc="book_enea_edge_getting_started"
+        targetptr="redundant_mgmt_com">Redundant Management Communication
+        in the <xi:include
+        href="../../s_docbuild/olinkdb/pardoc-names.xml"
+        xmlns:xi="http://www.w3.org/2001/XInclude"
+        xpointer="element(book_enea_edge_getting_started/1)" /></olink>
+        Manual.</para>
+      </listitem>
     </itemizedlist>
 
     <para><emphasis role="bold">Improvements:</emphasis></para>
@@ -218,4 +230,4 @@
       This could affect existing custom scripts using Python 2 syntax. Please 
       update these scripts accordingly in order to run in a Python 3 environment.</para>
   </section>
-</chapter>
\ No newline at end of file
+</chapter>
-- 
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