Help Center/ Enterprise Router/ Best Practices/ Using Enterprise Router and Central Network to Migrate the Network Set Up Through a Cloud Connection/ Network and Resource Planning
Updated on 2024-07-02 GMT+08:00
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Network and Resource Planning

Plan the network and required resources before, during, and after the migration.
  • Network Planning: Plan the VPC and enterprise router route tables.
  • Resource Planning: Plan the quantity, names, and parameters of cloud resources, such as cloud connection, central network, global connection bandwidth, ECS, and enterprise router.

Network Planning

During the migration, you need to add routes to the VPC and enterprise router route tables. For details, see Table 1.

The following figures show the network in different phases.

The routes in the figures are only examples for your reference. You need to plan routes based on service requirements.

Figure 1 Networking diagram before migration (cross-region VPC connectivity established using a cloud connection)
Figure 2 Networking diagram after migration (cross-region VPC connectivity established using enterprise routers and a central network)
Table 1 Network planning details

Route Table

Description

VPC route tables
Table 2 lists all the routes in the route tables.
  1. Before the migration, there are routes pointing to the cloud connection in the VPC route tables. The routes are used for communications between VPCs over the cloud connection.
  2. During the migration, to prevent route conflicts, you need to add routes in each VPC route table:
    1. A route is used for communications between the VPC and the enterprise router in the same region, with the destination set to a large CIDR block and next hop to the enterprise router.

      The route destination must include the VPC CIDR block and cannot be used by other services. In this example, the large CIDR block is 192.168.0.0/14, which includes three VPC CIDR blocks: 192.168.0.0/16, 192.169.0.0/16, and 192.170.0.0/16.

      NOTICE:

      The large CIDR block must include the CIDR blocks of all VPCs that need to communicate with each other. If one large CIDR block cannot include all VPC CIDR blocks, you can configure more large CIDR blocks.

    2. A route is used to verify that the VPCs can communicate with each other through the central network and enterprise routers. After the verification is complete, the route can be deleted.

      The route destination can be the IP address of an ECS in the VPC to be connected.

  3. During the migration, when you remove a VPC from the cloud connection, the route pointing to the cloud connection will be deleted from the corresponding VPC route table.
    NOTICE:

    After the migration, you can continue to use the routes with the destination set to the large CIDR block. You can also add routes with destinations that are the same as those of the original routes and then delete the routes with the destination set to the large CIDR block.

Enterprise router route tables

Table 3 lists all the routes in the route tables.

During the migration, add routes pointing to peering connection attachments in each enterprise router route table to forward traffic between VPCs through the enterprise routers and central network.

When a central network is set up to connect the enterprise routers, you must enable Default Route Table Association and Default Route Table Propagation for the enterprise routers. In this way, when an instance is added to an enterprise router, a route pointing to the attachment will be automatically added for the enterprise router.

Cloud connection route table

Table 4 lists the routes in the cloud connection route table.

After the migration is complete, the routes will be deleted when you delete the cloud connection.
Table 2 VPC route tables

VPC

Route Table

Destination

Next Hop Type

Next Hop

Route Type

Description

Phase

VPC-A

rtb-vpc-A

192.169.0.0/24

Cloud connection

CC-A-B-C

System

The route is destined for a subnet of VPC-B and is used to connect VPC-B using the cloud connection.
  • Before migration
  • During migration

192.170.0.0/24

Cloud connection

CC-A-B-C

System

The route is destined for a subnet of VPC-C and is used to connect VPC-C using the cloud connection.
  • Before migration
  • During migration

192.168.0.0/14

Enterprise router

ER-A

Custom

The route is destined for a large CIDR block and is used for VPC communications through the central network and enterprise routers.
  • During migration
  • After migration

192.169.0.148/32

Enterprise router

ER-A

Custom

The route is destined for an ECS in VPC-B to check whether VPC-A can communicate with VPC-B through the enterprise routers and central network.

During migration

192.170.0.131/32

Enterprise router

ER-A

Custom

The route is destined for an ECS in VPC-C to check whether VPC-A can communicate with VPC-C through the enterprise routers and central network.

During migration

VPC-B

rtb-vpc-B

192.168.0.0/24

Cloud connection

CC-A-B-C

System

The route is destined for a subnet of VPC-A and is used to connect VPC-A using the cloud connection.
  • Before migration
  • During migration

192.170.0.0/24

Cloud connection

CC-A-B-C

System

The route is destined for a subnet of VPC-C and is used to connect VPC-C using the cloud connection.
  • Before migration
  • During migration

192.168.0.0/14

Enterprise router

ER-B

Custom

The route is destined for a large CIDR block and is used for VPC communications through the central network and enterprise routers.
  • During migration
  • After migration

192.168.0.37/32

Enterprise router

ER-B

Custom

The route is destined for an ECS in VPC-A to check whether VPC-B can communicate with VPC-A through the enterprise routers and central network.

During migration

192.170.0.131/32

Enterprise router

ER-B

Custom

The route is destined for an ECS in VPC-C to check whether VPC-B can communicate with VPC-C through the enterprise routers and central network.

During migration

VPC-C

rtb-vpc-C

192.168.0.0/24

Cloud connection

CC-A-B-C

System

The route is destined for a subnet of VPC-A and is used to connect VPC-A using the cloud connection.
  • Before migration
  • During migration

192.169.0.0/24

Cloud connection

CC-A-B-C

System

The route is destined for a subnet of VPC-B and is used to connect VPC-B using the cloud connection.
  • Before migration
  • During migration

192.168.0.0/14

Enterprise router

ER-C

Custom

The route is destined for a large CIDR block and is used for VPC communications through the central network and enterprise routers.
  • During migration
  • After migration

192.168.0.37/32

Enterprise router

ER-C

Custom

The route is destined for an ECS in VPC-A to check whether VPC-C can communicate with VPC-A through the enterprise routers and central network.

During migration

192.169.0.148/32

Enterprise router

ER-C

Custom

The route is destined for an ECS in VPC-B to check whether VPC-C can communicate with VPC-B through the enterprise routers and central network.

During migration
Table 3 Enterprise router route tables

Enterprise Router

Route Table

Destination

Next Hop

Attached Resource

Route Type

Description

Phase

ER-A

defaultRouteTable

192.168.0.0/16

er-attach-VPC-A

VPC-A

Propagated

The route is destined for the CIDR block of VPC-A and is used for communications between VPC-A and enterprise router ER-A.
  • During migration
  • After migration

192.169.0.0/16

region-A-region-B

ER-B

Propagated

The route is destined for the CIDR block of VPC-B and is used for VPC communications through the central network and enterprise routers.
  • During migration
  • After migration

192.170.0.0/16

region-A-region-C

ER-C

Propagated

The route is destined for the CIDR block of VPC-C and is used for VPC communications through the central network and enterprise routers.
  • During migration
  • After migration

ER-B

defaultRouteTable

192.169.0.0/16

er-attach-VPC-B

VPC-B

Propagated

The route is destined for the CIDR block of VPC-B and is used for communications between VPC-B and enterprise router ER-B.
  • During migration
  • After migration

192.168.0.0/16

region-B-region-A

ER-A

Propagated

The route is destined for the CIDR block of VPC-A and is used for VPC communications through the central network and enterprise routers.
  • During migration
  • After migration

192.170.0.0/16

region-B-region-C

ER-C

Propagated

The route is destined for the CIDR block of VPC-C and is used for VPC communications through the central network and enterprise routers.
  • During migration
  • After migration

ER-C

defaultRouteTable

192.170.0.0/16

er-attach-VPC-C

VPC-C

Propagated

The route is destined for the CIDR block of VPC-C and is used for communications between VPC-C and enterprise router ER-C.
  • During migration
  • After migration

192.168.0.0/16

region-C-region-A

ER-A

Propagated

The route is destined for the CIDR block of VPC-A and is used for VPC communications through the central network and enterprise routers.
  • During migration
  • After migration

192.169.0.0/16

region-C-region-B

ER-B

Propagated

The route is destined for the CIDR block of VPC-B and is used for VPC communications through the central network and enterprise routers.
  • During migration
  • After migration
Table 4 Cloud connection route table

Cloud Connection

Destination

Network Instance

Description

Phase

CC-A-B-C

192.168.0.0/16

VPC-A

The route is destined for a subnet of VPC-A and is used to connect VPC-A using the cloud connection.
  • Before migration
  • During migration

192.169.0.0/16

VPC-B

The route is destined for a subnet of VPC-B and is used to connect VPC-B using the cloud connection.
  • Before migration
  • During migration

192.170.0.0/16

VPC-C

The route is destined for a subnet of VPC-C and is used to connect VPC-C using the cloud connection.
  • Before migration
  • During migration

Resource Planning

During the migration, you need to create cloud resources such as enterprise routers, a central network, and global connection bandwidths. After the migration is complete, you can delete the cloud connection. Table 5 describes all required resources in this practice.

The following resource planning details are only examples for your reference. You need to plan resources based on service requirements.

Table 5 Resource planning details

Resource

Quantity

Description

Phase

VPC

3

Three service VPCs are required for running workloads.

  • Name: Set it based on site requirements. In this example, the names are as follows:
    • Region A: VPC-A
    • Region B: VPC-B
    • Region C: VPC-C
  • IPv4 CIDR block: The CIDR blocks of VPCs must be unique. Plan the CIDR blocks based on site requirements. In this example, the CIDR blocks are as follows:
    • VPC-A: 192.168.0.0/16
    • VPC-B: 192.169.0.0/16
    • VPC-C: 192.170.0.0/16
  • Subnet: The subnet CIDR blocks that need to communicate with each other must be unique. Plan the subnets based on site requirements. In this example, the subnets are as follows:
    • subnet-A01: 192.168.0.0/24
    • subnet-B01: 192.169.0.0/24
    • subnet-C01: 192.170.0.0/24
  • Before migration
  • During migration
  • After migration

Enterprise router

3

An enterprise router is required in each region. The VPC in each region is attached to the corresponding enterprise router, and a peering connection attachment is created between every two enterprise routers.

  • Name: Set it based on site requirements. In this example, the names are as follows:
    • Region A: ER-A
    • Region B: ER-B
    • Region C: ER-C
  • ASN: Set different ASNs for enterprise routers. In this example, the ASNs are as follows:
    • ER-A: 64512
    • ER-B: 64513
    • ER-C: 64514
  • Default Route Table Association: Enable
  • Default Route Table Propagation: Enable
  • Auto Accept Shared Attachments: Set it based on site requirements. In this example, this option is enabled.
  • Attachment: Three attachments are required for each enterprise router. In this example, the attachments are as follows:
    ER-A
    • VPC attachment er-attach-VPC-A: connects the network between VPC-A and ER-A.
    • Peering connection attachment region-A-region-B: connects the network between ER-A and ER-B.
    • Peering connection attachment region-A-region-C: connects the network between ER-A and ER-C.
    ER-B
    • VPC attachment er-attach-VPC-B: connects the network between VPC-B and ER-B.
    • Peering connection attachment region-B-region-A: connects the network between ER-B and ER-A.
    • Peering connection attachment region-B-region-C: connects the network between ER-B and ER-C.
    ER-C
    • VPC attachment er-attach-VPC-C: connects the network between VPC-C and ER-C.
    • Peering connection attachment region-C-region-A: connects the network between ER-C and ER-A.
    • Peering connection attachment region-C-region-B: connects the network between ER-C and ER-B.
NOTICE:
  • When a central network is set up to connect the enterprise routers, you must enable Default Route Table Association and Default Route Table Propagation for the enterprise routers.
  • Do not enable Auto Add Routes when you create the VPC attachment.

    If this option is enabled, Enterprise Router automatically adds routes (with this enterprise router as the next hop and 10.0.0.0/8, 172.16.0.0/12, and 192.168.0.0/16 as the destinations) to all route tables of the VPC. During the migration, manually add routes with destinations set to the large CIDR block in the VPC route table.
  • During migration
  • After migration

Cloud connection

1

One cloud connection is required, and the three VPCs are loaded to it.

  • Name: Set it based on site requirements. In this example, CC-A-B-C is used.
  • Scenario: VPC
  • Load the three VPCs to the created cloud connection:
    • Region A: VPC-A
    • Region B: VPC-B
    • Region C: VPC-C
  • Before migration
  • During migration

Central network

1
A central network is required, with all enterprise routers are added to it as attachments.
  • Name: Set it based on site requirements. In this example, GCN-A-B-C is used.
  • Policy:
    • Region A: enterprise router ER-A
    • Region B: enterprise router ER-B
    • Region C: enterprise router ER-C
  • Cross-site connection bandwidths: You are advised to set the bandwidths the same as original bandwidths. You can also change the bandwidths based on site requirements.
    • Region A-Region B: 10 Mbit/s
    • Region A-Region C: 5 Mbit/s
    • Region B-Region C: 20 Mbit/s
  • During migration
  • After migration

Global connection bandwidth

3

Three global connection bandwidths are required to connect the cloud backbone networks in different regions.

  • Name: Set it based on site requirements. In this example, the names are as follows:
    • Global connection bandwidth for communications between region A and region B: bandwidth-A-B
    • Global connection bandwidth for communications between region A and region C: bandwidth-A-C
    • Global connection bandwidth for communications between region B and region C: bandwidth-B-C
  • Bandwidth Type: Set it based on site requirements. In this example, select Geographic-region because the three regions are in the same geographic region.
  • Geographic region: Set it based on site requirements. In this example, select Chinese Mainland.
  • Connect regions: Select the regions based on site requirements.
  • During migration
  • After migration

ECS

3
Create an ECS in each VPC to verify network connectivity.
  • Name: Set it based on site requirements. In this example, the names are as follows:
    • Region A: ECS-A
    • Region B: ECS-B
    • Region C: ECS-C
  • Image: Select an image based on site requirements. In this example, a public image (CentOS 7.9 64bit) is used.
  • Network: Select the VPC and subnet based on site requirements. In this example, the VPCs and subnets are as follows:
    • ECS-A: VPC-A, subnet-A01
    • ECS-B: VPC-B, subnet-B01
    • ECS-C: VPC-C, subnet-C01
  • Security Group: Select a security group based on site requirements. In this example, the security group sg-demo uses a general-purpose web server template.
  • Private IP addresses:
    • ECS-A: 192.168.0.37
    • ECS-B: 192.169.0.148
    • ECS-C: 192.170.0.131
  • Before migration
  • During migration
  • After migration