How Do I Route Traffic to 100.64.x.x Through an Enterprise Router?

Scenarios

A route with 100.64.x.x as the destination and an enterprise router as the next hop cannot be added to a VPC route table.

Solutions

If you want to route traffic to 100.64.x.x through an enterprise router, you need to create a transit VPC. Figure 1 shows the network diagram.

**Figure 1** Transit VPC network diagram

Figure 1 Transit VPC network diagram

The request traffic from the service VPC to the on-premises data center will be forwarded through the transit VPC, but the response traffic will not. For details, see Table 1.

Table 1 Network traffic flows

Path

Description

Request traffic: service VPC → transit VPC → enterprise router → virtual gateway → on-premises data center

  1. The service VPC route table has a route with the VPC peering connection as the next hop to forward traffic from the service VPC to the transit VPC.

  2. The transit VPC route table has a route with next hop set to the enterprise router to forward traffic from the transit VPC to the enterprise router.

  3. The enterprise router route table has a route with next hop set to virtual gateway attachment to forward traffic from the enterprise router to the virtual gateway.

  4. The virtual gateway is connected to the virtual interface. Traffic from the virtual gateway is forwarded to the physical connection through the remote gateway of the virtual interface

  5. Traffic is sent to the on-premises data center over the connection.

Response traffic: on-premises data center → virtual gateway → enterprise router → service VPC

  1. Traffic is forwarded to the virtual interface through the connection.

  2. The virtual interface is connected to the virtual gateway. Traffic from the virtual interface is forwarded to the virtual gateway through the local gateway of the virtual interface.

  3. Traffic is forwarded from the virtual gateway to enterprise router.

  4. The enterprise router route table has a route with next hop set to the service VPC attachment to forward traffic from the enterprise router to the service VPC.

The required resources and routes are as follows:

  • Table 2: Required service VPC, transit VPC, enterprise router, and Direct Connect connection that connects the cloud and the on-premises data center

  • Table 3: Required routes of the service VPC, transit VPC, and enterprise router

Table 2 Resource planning

Resource

Quantity

Description

VPC

2

Service VPC that your services are deployed and needs to be attached to the enterprise router

  • VPC CIDR block: 10.1.0.0/16

  • Subnet CIDR block: 10.1.1.0/24

Transit VPC that is connected to the service VPC over a VPC peering connection and needs to be attached to the enterprise router

  • VPC CIDR block: 192.168.0.0/16

  • Subnet CIDR block: 192.168.1.0/24

Enterprise router

1

Three attachments on the enterprise router:

  • Service VPC attachment: service VPC

  • Transit VPC attachment: transit VPC

  • Virtual gateway attachment: virtual gateway of Direct Connect

Direct Connect

1

  • Connection

  • Virtual gateway that needs to be attached to the enterprise router

  • Virtual interface

    • Local gateway: 10.0.0.1/30

    • Remote gateway: 10.0.0.2/30

    • Remote subnet: subnet of the on-premises data center (100.64.x.x)

Table 3 Route planning

Route Table

Destination

Next Hop

Route Type

Service VPC

100.64.x.x

VPC peering connection

Static route (custom)

Transit VPC

2.2.2.2/32

Note

2.2.2.2/32 is mandatory and must be added.

VPC peering connection

Static route (custom)

0.0.0.0/0

Enterprise router

Static route (custom)

Enterprise router

10.1.0.0/16

Service VPC attachment

Propagated route

100.64.x.x

Virtual gateway attachment

Propagated route

  1. Create a transit VPC, attach it to the enterprise router, and associate the transit VPC with the default route table of the enterprise router.

    • The subnet of the transit VPC cannot overlap with that of the service VPC, or the VPC peering connection to be created in 2 cannot take effect.

    • The transit VPC cannot have the following situations. Otherwise, the default route (0.0.0.0/0) to be configured in 3 cannot forward traffic.

      • An ECS in the VPC has an EIP bound.

      • The VPC is being used by ELB, NAT Gateway, VPC Endpoint, or DCS.

  2. Create a VPC peering connection between the service VPC and transit VPC.

    Important

    You do not need to add routes for the VPC peering connection. For details about the routes to be added, see 3.

  3. Add routes to the VPC route tables.

    For details about required routes, see Table 3.

    1. Add the route to the service VPC route table.

    2. Add two routes to the transit VPC route table.

last updated: 2024-06-30 00:26