Each attachment can be associated with one route table for:

Packet forwarding: Packets from the attachment are forwarded through the routes specified in the associated route table.
Route propagation: The routes in the associated route tables are automatically propagated to the route table of the attachment.

Figure 1 Associations

**Table 1** Association description
Attachment Type	Route Learning	Way to Create Association	Description
VPC	Not supported	Auto creation: If Default Route Table Association is enabled and the default association route table is specified, attachments are automatically associated with the default association route table. If you want to enable this function when you create an enterprise router, refer to Creating an Enterprise Router. If you want to enable this function after an enterprise router is created, refer to Modifying an Enterprise Router. Manual creation: You can select a route table and create an association in it to associate an attachment with the route table. For details, see Creating an Association for an Attachment in a Route Table.	Each attachment can only be associated with one route table. Associations between attachments in Association Overview are described as follows: Auto creation: The system automatically associates attachments, such as VPC 1, VPC 2, and virtual gateway 1 attachments, with the default route table of the enterprise router. Manual creation: You need to manually create associations in the custom route table of the enterprise router for attachments, such as VPC 3, VPC 4, and virtual gateway 2 attachments.
Virtual gateway	Supported

Association Overview