Help Center/ Enterprise Router/ User Guide/ Route Tables/ Route Table Overview
Updated on 2026-11-04 GMT+08:00
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Route Table Overview

A route table controls how an enterprise router routes packets. It contains attachment associations, propagations, and routes. You can create custom route tables for an enterprise router, add routes to the route tables, and create associations and propagations for attachments.

  • You can create an association in the route table of an enterprise router to associate an attachment with the route table. After the association is created, packets from the attachment are forwarded based on the association route table, and the attachment network can automatically learn the route information from the association route table.
  • You can create a propagation for an attachment in the route table of an enterprise router to automatically learn the route information of the attachment. This eliminates the need for manual configuration and improves configuration efficiency.

Route tables are classified into custom and default route tables, as detailed in Table 1.

Table 1 Route table types

Route Table Type

Description

Custom route table
  • A custom route table is an additional route table you optionally create for an enterprise router.
  • An enterprise router can have multiple custom route tables. You can associate attachments with different route tables to enable communications or isolation between network instances.

Default route table

There are two types of default route tables: default association route table and default propagation route table. You can specify a route table both as the default association route table and the default propagation route table. You can also specify one route table as the default association route and another route table as the default propagation route table.

  • If Default Route Table Association is enabled and the default association route table is specified, the system will automatically associate new attachments with this route table.

    If no default association route table is specified, a route table named defaultRouteTable will be created and used as the default association route table.

  • If Default Route Table Propagation is enabled and the default propagation route table is specified, the system will automatically create propagations for new attachments in this route table.

    If no default propagation route table is specified, a route table named defaultRouteTable will be created and used as the default propagation route table.

  • If both Default Route Table Association and Default Route Table Propagation are enabled but the default association route table and the default propagation route table are not specified, the route table named defaultRouteTable will be used as both the default association route table and the default propagation route table.
  • If there is already a route table named defaultRouteTable, no additional defaultRouteTable will be created.
  • You can replace the default route table with a custom route table if needed.

Route Table Configuration Example

You can associate VPC attachments with different route tables of an enterprise router to enable communications or isolation between VPCs in the same region.

An enterprise has four VPCs in region A, as shown in Table 2. VPC1, VPC2, and VPC3 must be isolated from each other, but they must be able to communicate with VPC4 to access public services.

Table 2 Service deployment solution

VPC

Service

Description

VPC1

Service A

Independent service line

VPC2

Service B

Independent service line

VPC3

Service C

Independent service line

VPC4

Public service

Shared services, such as the O&M platform and public components

You can create two custom route tables for the enterprise router and associate the four VPC attachments with different route tables for isolation and communication. Figure 1 shows the networking plan. VPC1 attachment, VPC2 attachment, and VPC3 attachment are associated with route table 1, and VPC4 attachment is associated with route table 2.

Figure 1 Network planning for isolating VPCs in the same region
Table 3 Network traffic flows

Path

Description

Request traffic: from VPC 1 to VPC 4
  1. In the route table of VPC 1, there is a route with the next hop set to the enterprise router to forward traffic from VPC 1 to the enterprise router.
  2. VPC 1 is associated with route table 1 of the enterprise router. This route table has a route with the next hop set to VPC 4 attachment to forward traffic from the enterprise router to VPC 4.

Response traffic: from VPC 4 to VPC 1
  1. In the route table of VPC 4, there is a route with the next hop set to the enterprise router to forward traffic from VPC 4 to the enterprise router.
  2. VPC 4 is associated with route table 2 of the enterprise router. This route table has a route with the next hop set to VPC 1 attachment to forward traffic from the enterprise router to VPC 1.
Parent topic: Route Tables