Introduction to EMCC
----------------------

.. _19.2.1|VOSS-205:

Overview 
..........

Extension Mobility Cross Cluster (EMCC) extends VOSS Automate's current extension
mobility functionality to allow a user to log in to a device from within a
connected cluster, anywhere in the world. This allows the user to retain the
settings, services, and lines they're familiar with at their home location.

VOSS Automate automates most of the EMCC provisioning to enable this feature to work
on all dial plans across multiple Cisco Unified Communications Manager (CUCM)
clusters that are managed by the same platform instance. A small number of manual
configurations remain, specifically around network security, which is outlined in
a separate section. VOSS Automate only automates provisioning of the home cluster in
cases where the CUCM clusters are managed by separate platforms, that is,
cross-cluster configuration across multiple platforms is not supported.


EMCC Use Case
.............

The table describes a scenario where a user from the HOME cluster goes to the VISITING cluster and 
logs on to a phone. The two clusters can be in different countries/territories. The cluster is EMCC-enabled. The 
user is also subscribed to the EMCC service. 

.. tabularcolumns:: |p{5cm}|p{10cm}|

+-----------------------+----------------------------+
| HOME Cluster          | VISITING Cluster           |
+=======================+============================+
| User Profile          | Phone (with Geolocation)   |
|                       |                            |
+-----------------------+----------------------------+
| Geolocation Filter    |                            |
+-----------------------+----------------------------+
| Roaming Device Pool   |                            |
| (with Geolocation)    |                            |
+-----------------------+----------------------------+


In this scenario: 

* The user cannot be authenticated in the VISITING cluster, but since the cluster
  is EMCC enabled, and the phone is subscribed to the EMCC service, the cluster
  searches for the user in defined EMCC remote clusters.
* Once the user (also subscribed to the EMCC service) is authenticated, the phone
  is unregistered from the VISITING cluster, and re-registered to the HOME cluster.
* The geolocation of the phone is sent to the HOME cluster, which allows the HOME
  cluster to associate the relevant roaming device pool to the user's phone using
  the geolocation filter.
* The phone behaves and dials exactly the same as if the user is logged in at the
  HOME cluster. Additionally, all the user's settings and preferences are preserved.
* Calls to the HOME cluster emergency numbers as well as the VISITING cluster
  emergency numbers break out at the VISITING cluster (physical location).


.. note:: 
  
   * Various other elements (such as trunks and EMCC countries) must be 
     configured on both the HOME cluster and the VISITING cluster to ensure that this feature works.
   * Refer to the "Cisco Unified Communications Manager Features and Services Guide"
     for more information about the EMCC feature.



Configuring EMCC using VOSS Automate
.....................................

Before configuring EMCC using VOSS Automate, ensure that the following parameters 
have already been configured on each required EMCC cluster (CUCM) located at the relevant Customers:

* EMCC feature configuration, such as Default TFTP Server for EMCC Login Device,
  EMCC Geolocation Filter