-**Upgrade Manager**:Mainly responsible for upgrading process control. Physical
-nodes information of each node is saved in upgrade manager.
-**VIM Interface**:Mainly responsible for the external interface, include
-Vi-Vnfm, Or-Vi. This module stores VNFO and VNFM external information such as
-address and authentication.
-**Cloud Manager**:Mainly responsible for virtualization resources management,
-which might be considered made up of Openstack and SDN control node.
-**System Support**:Provide the upper software running environment, including:
-OS, HA, etc. To upgrade the upper software is based on this module.
+
+- **Upgrade Manager**
+
+Mainly responsible for control of the upgrade process.The Escalator is required
+to know the software deployment information of the platform and will use these
+information during the upgrading. It will be collected from some place, such
+as the Installer, Deploy Manager and Escalator itself, etc.
+
+- **VIM Interface**:
+
+Mainly responsible for the external interface, include Vi-Vnfm, Or-Vi. This
+module stores VNFO and VNFM external information such as address and
+authentication.
+
+- **Cloud Manager**:
+
+Mainly responsible for virtualization resources management,which might be
+considered made up of Openstack and SDN control node.
+
+- **System Support**:
+
+This layer is the runtime support environment of upper layers, e.g. Cloud
+Manager and VIM interface., including:OS, HA, etc. To upgrade the upper
+software is based on this module.