:original_name: er_01_0035.html

.. _er_01_0035:

Propagation Overview
====================

You can create a propagation for each attachment to propagate routes to one or more route tables on an enterprise router.

If you do not want to create a propagation, you can manually add static routes for attachments to the route tables.

.. _er_01_0035__fig16423163124017:

.. figure:: /_static/images/en-us_image_0000001347809009.png
   :alt: **Figure 1** Propagated routes and static routes

   **Figure 1** Propagated routes and static routes

.. table:: **Table 1** Propagation description

   +-----------------+-----------------+-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
   | Attachment Type | Propagated Info | Way to Create Propagation                                                                                                                                                                                         | Description                                                                                                                                                                                                     |
   +=================+=================+===================================================================================================================================================================================================================+=================================================================================================================================================================================================================+
   | VPC             | VPC CIDR blocks | -  Auto creation: If **Default Route Table Propagation** is enabled and the default propagation route table is specified, attachments automatically propagate routes to the default propagation route table.      | An attachment can be propagated to different route tables. You can create propagations for attachments in :ref:`Figure 1 <er_01_0035__fig16423163124017>` as follows:                                           |
   |                 |                 |                                                                                                                                                                                                                   |                                                                                                                                                                                                                 |
   |                 |                 |    -  If you want to enable this function when you create an enterprise router, refer to :ref:`Creating an Enterprise Router <er_01_0069>`.                                                                       | -  Auto creation: Propagations are automatically created for the attachments, such as VPC 1, VPC 2, and virtual gateway 1 attachments, in the default propagation route table of the enterprise router.         |
   |                 |                 |    -  If you want to enable this function after an enterprise router is created, refer to :ref:`Modifying an Enterprise Router <er_01_0013>`.                                                                     | -  Manual creation: You need to manually create propagations in the custom route table of the enterprise router for attachments, such as VPC 1, virtual gateway 1, and virtual gateway 2 attachments.           |
   |                 |                 |                                                                                                                                                                                                                   | -  No propagation: If you do not want to use propagated routes, you need to manually add static routes to the custom route table of the enterprise router for attachments, such as VPC 3 and VPC 4 attachments. |
   |                 |                 | -  Manual creation: You can select a route table and create a propagation for an attachment in the route table. For details, see :ref:`Creating a Propagation for an Attachment in the Route Table <er_01_0036>`. |                                                                                                                                                                                                                 |
   +-----------------+-----------------+-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
   | Virtual gateway | All routes      |                                                                                                                                                                                                                   |                                                                                                                                                                                                                 |
   +-----------------+-----------------+-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+